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beejay&esskay, Are these numbers for the 'Marker Type' or the 'Setting'? If they are 'Marker Type's - where did you get the rest of these numbers? Is this a currant list from NGS? Is there a list for all to see? This list is taken from the NGS site.... Quote... A.12 Monumentation (Marker) Code The monumentation code is a one or two character code which identifies the type of monument object or landmark which represents the control point. Monumentation codes are subdivided into five monument categories: disk monuments (D), landmark monuments (L), other monuments (O), rod monuments ®, and underground monuments (U). Some monumentation codes appear in more than one category. The monumentation codes are also divided into generalized categories (see the grayed-out headings) for your convenience. This table is represented by the MONUCAT.DAT, and the MONUMENT.DAT ASCII files. Monumentation Category Monumentation Code Definition Not for Landmark Stations O, U A Aluminum marker other than a disk included elsewhere in table O, U B Bolt O, U C Cap of cap-and-bolt pair D DA Astro pier disk D DB Bench mark disk D, U DD Survey disk (other agency) D, U DE Traverse station disk D DG Gravity station disk D, U DH Horizontal control disk D DJ Tidal station disk D DK Gravity reference mark disk D DM Magnetic station disk D, U DO Disk not specified (see description) O DP Base line pier disk D DQ Calibration base line disk D, U DR Reference mark disk D, U DS Triangulation station disk D DT Topographic station disk D DU Boundary marker D DV Vertical control disk D DW NOS hydrographic survey disk D, U DZ Azimuth mark disk O, U E Earthenware pot R F Flange-encased rod O, U G Glass bottle O, U H Drill hole R, U I Metal rod O, U J Earthenware jug O, U K Clay tile pipe O, U L Gravity plug O, U M Ammo shell casing O, U N Nail O, U O Chiseled circle O, U P Pipe cap O, U Q Chiseled square O, U R Rivet O, U S Spike O, U T Chiseled triangle O, U U Concrete post (without other marks) O, U V Stone monument O, U W Unmonumented O, U X Chiseled cross O, U Y Drill hole in brick O, U Z See description Landmarks not Listed L 0 Other mark or intersection station, see description Natural Objects L 01 Lone tree L 02 Conspicuous rock L 03 Mountain peak L 04 Rock pinnacle L 05 Rock awash Waterfront Landmarks and Visual Aids to Navigation L 11 Piling L 12 Dolphin L 13 Lighthouse L 14 Navigation light L 15 Range marker L 16 Daybeacon L 17 Flag tower L 18 Signal mast Aeronautical and Electronic Aids to Navigation L 21 Airport beacon L 22 Airway beacon L 23 VOR antenna L 24 REN antenna L 25 Radar antenna L 26 Spherical radome L 27 Radio range mast L 28 LORAN mast Broadcast and Communications Facilities L 41 Antenna mast L 42 Radio/TV mast L 43 Radio/TV tower L 44 Microwave mast L 45 Microwave tower Tanks and Towers L 51 Tank L 52 Standpipe tank L 53 Elevated tank L 54 Water tower L 55 Tower L 56 Skeleton tower L 57 Lookout tower L 58 Control tower Miscellaneous Landmarks L 61 Pole L 62 Flagpole L 63 Stack L 64 Silo L 65 Grain elevator L 66 Windmill L 67 Oil derrick L 68 Commercial sign L 69 Regulatory sign L 70 Monument L 71 Boundary monument L 72 Cairn L 73 Lookout house L 74 Large cross L 75 Belfry Features of a Building L 81 Gable L 82 Finial L 83 Flagstaff L 84 Lightning rod L 85 Chimney L 86 Cupola L 87 Dome L 88 Observatory dome L 89 Spire L 90 Church spire L 91 Church cross L 92 Antenna on roof L 93 Microwave antenna on building L 94 Rooftop ventilator L 95 Rooftop blockhouse Unquote... (Please note that the first letter is for something else) We had found it in Zhanna's post in this Thread but, we have used parkrrrr's format. I am going to work shortly and John is in bed now, but if you have a more complete list that is official, please post it for all to see so we can all vote if we should use the 'updated' - "beejay&esskay" version, or the NGS version. We are happy to consider ways to make this contest better. If everyone agrees, then John will give his ruling.... Happy hunting! Shirley~

How about some serious competition with a (small) prize for the winner? We have an Idea for a friendly game and we are willing to put up a 1 year premium membership (for GC.com) (or if there is enough interest maybe we could get a disk for the prize) to the winner. For the rules, we suggest the following: 1) There will be a 6 month time period to complete (as best as possible) the following Marker Type list. 2) You will need to get a picture of each type of Mark and include your GPSr in the picture. The GPSr must show the coordinates and the Date! If the GPSr can not be read then it will not count! 3) Only marks found after the start of the competition will count. This will start everyone on an even playing field. 4) Only one of each type will be applied to your total. 5) We will have a thread where you can post a link to the PID# of those you have found. (Try to post your finds in groups to help make it a bit easier to keep track of your finds.) Please let us know which type of mark you are submitting. (As in - PID# GQ0323 = V = stone monument, PID# GP0572 = 21 = airport beacon, PID# FS0759 = Q = chiseled square) 6) You may revisit previous finds and include them in your competition list of types. (Make sure your GPSr shows the date to get credit for it, though) The marker type is listed just below the designation on the GC.com datasheets. Here is a link to a thread where we described how we use GSAK to find the different types in our area. Sorting marker types Feel free to use what ever sorting method you prefer to get you the highest number of marker types. How does Nov 1st sound as the starting date? Will that give you enough time to get a game plan ready? Is 6 months a good length of time to run the competition? Any suggestions? Are you interested? Sound like fun? The list of benchmark types... 01 = LONE TREE 02 = CONSPICUOUS ROCK 03 = MOUNTAIN PEAK 04 = ROCK PINNACLE 05 = ROCK AWASH 11 = PILING 12 = DOLPHIN 13 = LIGHTHOUSE 14 = NAVIGATION LIGHT 15 = RANGE MARKER 16 = DAYBEACON 17 = FLAG TOWER 18 = SIGNAL MAST 21 = AIRPORT BEACON 22 = AIRWAY BEACON 25 = RADAR ANTENNA 26 = SPHERICAL RADOME 27 = RADIO RANGE MAST 28 = LORAN MAST 41 = ANTENNA MAST 42 = RADIO/TV MAST 43 = RADIO/TV TOWER 44 = MICROWAVE MAST 45 = MICROWAVE TOWER 51 = TANK 52 = STANDPIPE TANK 53 = ELEVATED TANK 54 = WATER TOWER 55 = TOWER 56 = SKELETON TOWER 57 = LOOKOUT TOWER 58 = CONTROL TOWER 61 = POLE 62 = FLAGPOLE 63 = STACK 64 = SILO 65 = GRAIN ELEVATOR 66 = WINDMILL 67 = OIL DERRICK 68 = COMMERCIAL SIGN 69 = REGULATORY SIGN 70 = MONUMENT 71 = BOUNDARY MONUMENT 72 = CAIRN 73 = LOOKOUT HOUSE 74 = LARGE CROSS 75 = BELFRY 81 = GABLE 82 = FINIAL 83 = FLAGSTAFF 84 = LIGHTNING ROD 85 = CHIMNEY 86 = CUPOLA 87 = DOME 88 = OBSERVATORY DOME 89 = SPIRE 90 = CHURCH SPIRE 91 = CHURCH CROSS 92 = ANTENNA ON ROOF 93 = MICROWAVE ANTENNA ON BUILDING 94 = ROOFTOP VENTILATOR 95 = ROOFTOP BLOCKHOUSE A = ALUMINUM MARKER B = BOLT C = CAP OF CAP-AND-BOLT PAIR DA = ASTRO MARKER (USUALLY A DISK) DB = BENCH MARK DISK DD = SURVEY DISK DE = TRAVERSE STATION DISK DG = GRAVITY STATION DISK DH = HORIZONTAL CONTROL DISK DJ = TIDAL STATION DISK DK = GRAVITY REFERENCE MARK DISK DM = MAGNETIC STATION DISK DO = NOT SPECIFIED OR SEE DESCRIPTION DP = BASE LINE PIER DQ = CALIBRATION BASE LINE DISK DR = REFERENCE MARK DISK DS = TRIANGULATION STATION DISK DT = TOPOGRAPHIC STATION DISK DU = BOUNDARY MARKER DV = VERTICAL CONTROL DISK DW = NOS HYDROGRAPHIC SURVEY DISK DZ = AZIMUTH MARK DISK E = EARTHENWARE POT F = FLANGE-ENCASED ROD G = GLASS BOTTLE H = DRILL HOLE I = METAL ROD J = EARTHENWARE JUG K = CLAY TILE PIPE L = ABSOLUTE GRAVITY STATION PLUG M = AMMO SHELL CASING N = NAIL O = CHISELED CIRCLE P = PIPE CAP Q = CHISELED SQUARE R = RIVET S = SPIKE T = CHISELED TRIANGLE U = CONCRETE POST V = STONE MONUMENT W = UNMONUMENTED X = CHISELED CROSS Y = DRILL HOLE IN BRICK Z = SEE DESCRIPTION This post brought to you by John & Shirley - 2oldfarts (the rockhounders)

These type marks are usually of more imporatance and thus the added measures to make them less subject to enviromental conditions affecting the stability of the mark. Airports and CORS stations is where you might find these.. AA8048 *********************************************************************** AA8048 FBN - This is a Federal Base Network Control Station. AA8048 DESIGNATION - PORTAGE A AA8048 PID - AA8048 AA8048 STATE/COUNTY- MI/HOUGHTON AA8048 USGS QUAD - OSKAR (1975) AA8048 AA8048 *CURRENT SURVEY CONTROL AA8048 ___________________________________________________________________ AA8048* NAD 83(1994)- 47 13 37.82095(N) 088 37 31.04750(W) ADJUSTED AA8048* NAVD 88 - 192.928 (meters) 632.96 (feet) ADJUSTED AA8048 ___________________________________________________________________ AA8048 X - 104,103.487 (meters) COMP AA8048 Y - -4,338,042.251 (meters) COMP AA8048 Z - 4,659,069.331 (meters) COMP AA8048 LAPLACE CORR- -7.93 (seconds) DEFLEC99 AA8048 ELLIP HEIGHT- 159.42 (meters) (06/11/02) GPS OBS AA8048 GEOID HEIGHT- -33.55 (meters) GEOID03 AA8048 DYNAMIC HT - 192.961 (meters) 633.07 (feet) COMP AA8048 MODELED GRAV- 980,783.6 (mgal) NAVD 88 AA8048 AA8048 HORZ ORDER - A AA8048 VERT ORDER - FIRST CLASS II AA8048 ELLP ORDER - FOURTH CLASS I AA8048 AA8048.This is a reference station for the UPPER KEWEENAW 1 AA8048.National Continuously Operating Reference Station (KEW1). AA8048 AA8048.The horizontal coordinates were established by GPS observations AA8048.and adjusted by the National Geodetic Survey in September 1995. AA8048 AA8048.The orthometric height was determined by differential leveling AA8048.and adjusted by the National Geodetic Survey in July 2002. AA8048 AA8048.The X, Y, and Z were computed from the position and the ellipsoidal ht. AA8048 AA8048.The Laplace correction was computed from DEFLEC99 derived deflections. AA8048 AA8048.The ellipsoidal height was determined by GPS observations AA8048.and is referenced to NAD 83. AA8048 AA8048.The geoid height was determined by GEOID03. AA8048 AA8048.The dynamic height is computed by dividing the NAVD 88 AA8048.geopotential number by the normal gravity value computed on the AA8048.Geodetic Reference System of 1980 (GRS 80) ellipsoid at 45 AA8048.degrees latitude (g = 980.6199 gals.). AA8048 AA8048.The modeled gravity was interpolated from observed gravity values. AA8048 AA8048; North East Units Scale Factor Converg. AA8048;SPC MI N - 272,895.291 7,876,915.700 MT 1.00003831 -1 10 29.1 AA8048;SPC MI N - 895,325.76 25,842,899.28 iFT 1.00003831 -1 10 29.1 AA8048;UTM 16 - 5,231,690.617 376,962.287 MT 0.99978605 -1 11 35.5 AA8048 AA8048! - Elev Factor x Scale Factor = Combined Factor AA8048!SPC MI N - 0.99997501 x 1.00003831 = 1.00001332 AA8048!UTM 16 - 0.99997501 x 0.99978605 = 0.99976107 AA8048 AA8048 SUPERSEDED SURVEY CONTROL AA8048 AA8048 ELLIP H (09/21/95) 159.44 (m) GP( ) 2 1 AA8048 NAVD 88 (06/11/02) 192.93 (m) 633.0 (f) LEVELING 3 AA8048 AA8048.Superseded values are not recommended for survey control. AA8048.NGS no longer adjusts projects to the NAD 27 or NGVD 29 datums. AA8048.See file dsdata.txt to determine how the superseded data were derived. AA8048 AA8048_U.S. NATIONAL GRID SPATIAL ADDRESS: 16TCT7696231691(NAD 83) AA8048_MARKER: I = METAL ROD AA8048_SETTING: 59 = STAINLESS STEEL ROD IN SLEEVE (10 FT.+) AA8048_STAMPING: PORTAGE A 1994 AA8048_MARK LOGO: NGS AA8048_PROJECTION: FLUSH AA8048_MAGNETIC: N = NO MAGNETIC MATERIAL AA8048_STABILITY: B = PROBABLY HOLD POSITION/ELEVATION WELL AA8048_SATELLITE: THE SITE LOCATION WAS REPORTED AS SUITABLE FOR AA8048+SATELLITE: SATELLITE OBSERVATIONS - July 17, 2001 AA8048_ROD/PIPE-DEPTH: 15.5 meters AA8048_SLEEVE-DEPTH : 1.20 meters AA8048 AA8048 HISTORY - Date Condition Report By AA8048 HISTORY - 1994 MONUMENTED NGS AA8048 HISTORY - 19951212 GOOD MNDT AA8048 HISTORY - 19960519 GOOD NGS AA8048 HISTORY - 19960709 GOOD NGS AA8048 HISTORY - 20010425 GOOD MIDT AA8048 HISTORY - 20010717 GOOD MIDT AA8048 AA8048 STATION DESCRIPTION AA8048 AA8048'DESCRIBED BY NATIONAL GEODETIC SURVEY 1994 (CFS) AA8048'STATION IS LOCATED ABOUT 11 KM (6.85 MI) NORTH OF HANCOCK, ON THE EAST AA8048'SIDE OF THE CONFLUENCE OF PORTAGE LAKE AND LAKE SUPERIOR, AT THE WEST AA8048'END OF A CLEARED AREA ON THE WEST SIDE OF BEAR LAKE ROAD ABOUT 0.08 KM AA8048'(0.05 MI) NORTH OF A CABLE GATE AT THE OLD COAST GUARD STATION, IN THE AA8048'NORTHEAST 1/4 OF SECTION 28, T 55 N, R 34 W. OWNERSHIP--US COAST AA8048'GUARD, ROUTE 1, BOX 81, HANCOCK MI 49930. CONTACT DICK OTT PHONE AA8048'906-482-5620 IN HANCOCK, OR JIM GLAZ, USCG SAULT STE MARIE PHONE AA8048'906-635-3262. AA8048' AA8048'TO REACH FROM THE CENTER OF THE U.S. HIGHWAY 41 BRIDGE BETWEEN HANCOCK AA8048'AND HOUGHTON, GO NORTH, THEN WEST ON HIGHWAY 41 FOR 1.66 KM (1.05 MI) AA8048'TO A FORK. KEEP LEFT, WEST, THEN NORTH ON STATE HIGHWAY 203 FOR 14.03 AA8048'KM (8.70 MI) TO A CROSSROAD. TURN LEFT, WEST, THEN SOUTH ON BEAR LAKE AA8048'ROAD FOR 0.48 KM (0.30 MI) TO A CABLE GATE AT THE OLD COAST GUARD AA8048'STATION. PASS THROUGH GATE AND CONTINUE SOUTH ON PAVED ROAD FOR 30 M AA8048'(98.4 FT) TO A SAND ROAD ON THE RIGHT JUST NORTH OF A ONE CAR WHITE AA8048'GARAGE, TURN RIGHT AND GO WEST-SOUTHWEST FOR 0.2 KM (0.10 MI) ON SAND AA8048'ROAD TO A GRASS LANE ON THE RIGHT. TURN RIGHT AND GO NORTHWEST THEN AA8048'NORTH ON THE GRASS THEN SAND LANE FOR ABOUT 0.15 MI (0.24 KM) TO THE AA8048'STATION ON THE LEFT. AA8048' AA8048'STATION MARK IS A PUNCH HOLE TOP CENTER ON A STEEL ROD ENCASED IN A AA8048'PVC PIPE WITH LOGO CAP SET IN A CONCRETE POST FLUSH WITH THE GROUND. AA8048'IT IS ABOUT 117.0 M (383.9 FT) WEST OF CENTER OF BEAR LAKE ROAD, 35.3 AA8048'M (115.8 FT) WEST OF THE WEST CORNER OF 1 M (3.3 FT) BY 1.5 M (4.9 FT) AA8048'SQUARE CONCRETE BASE FOR AN ANTENNA, 44.5 M (146.0 FT) EAST OF METAL AA8048'RETAINING WALL AT EDGE OF WATER, 2.9 M (9.5 FT) WEST OF THE CENTER OF AA8048'SAND LANE, AND 1.1 M (3.6 FT) EAST-SOUTHEAST OF A FIBERGLASS WITNESS AA8048'POST. AA8048 AA8048 STATION RECOVERY (1995) AA8048 AA8048'RECOVERY NOTE BY MN DEPT OF TRANSP 1995 (DKH) AA8048'THE MARK WAS RECOVERED IN GOOD CONDITION AS DESCRIBED. RECOVERY NOTE AA8048'BY DAVID K. HERDER, TYPED BY J.E.M. AA8048 AA8048 STATION RECOVERY (1996) AA8048 AA8048'RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1996 (RPB) AA8048'RECOVERED AS DESCRIBED. AA8048 AA8048 STATION RECOVERY (1996) AA8048 AA8048'RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1996 (GAS) AA8048'14.0 KM (8.70 MI) NORTHERLY ALONG STATE HIGHWAY 203 FROM THE JUNCTION AA8048'OF U.S. HIGHWAY 41 IN HANCOCK, THENCE 0.4 KM (0.25 MI) WESTERLY ALONG AA8048'BEAR LAKE ROAD, 103.3 M (338.9 FT) WEST OF THE ROAD CENTER, 85.4 M AA8048'(280.2 FT) WEST OF THE NORTHWEST CORNER OF THE MOST WESTERLY OF 2 AA8048'SMALL BUILDINGS, 54.8 M (179.8 FT) NORTH OF BENCH MARK 2065, 32.8 M AA8048'(107.6 FT) WEST OF THE SOUTHWEST CORNER OF A FENCE ENCLOSING AN AA8048'ANTENNA, AND 1.1 M (3.6 FT) EAST OF A WITNESS POST. NOTE--ACCESS TO AA8048'THE DATUM POINT IS THROUGH A 5-INCH LOGO CAP. THE SLEEVE DEPTH DOES AA8048'NOT MEET THE SPECIFICATIONS FOR A CLASS A MARK. THE MONUMENT IS ON AA8048'PROPERTY OWNED BY THE U.S. COAST GUARD, ROUTE 1, BOX 81, HANCOCK, MI AA8048'49930, TELEPHONE NUMBER (906) 482-5620. AA8048 AA8048 STATION RECOVERY (2001) AA8048 AA8048'RECOVERY NOTE BY MICHIGAN DEPARTMENT OF TRANSPORTATION 2001 (SHN) AA8048'RECOVERED IN GOOD CONDITION. AA8048 AA8048 STATION RECOVERY (2001) AA8048 AA8048'RECOVERY NOTE BY MICHIGAN DEPARTMENT OF TRANSPORTATION 2001 (ASK) AA8048'THE STATION WAS RECOVERED ON 07-17-2001 IN GOOD CONDITION AS DESCRIBED AA8048'BY NGS. AA8048'

There is a 50 mile long strecth of NOS/USLS marks in upper Michigan that run from Port Inland near Gulliver on Lake Michigan to Marquette on Lake Superior. All the rod driven marks in this run are set about 1 ft more or less below ground level. It was a way to protect them, if they are on the surface they can be hit or knocked out of position very easily. Bury them and they will survive a lot longed. Only problem is that its makes it harded to find them when the sruface references are gone. Here is one I found in 2000, if we had not set a NGS orange witness post, the USPSQD would have never found it, the pole was cuf-off and rotting, hiding.. 1 National Geodetic Survey, Retrieval Date = SEPTEMBER 24, 2005 RK0390 *********************************************************************** RK0390 DESIGNATION - LSC 7 B 42 RK0390 PID - RK0390 RK0390 STATE/COUNTY- MI/MARQUETTE RK0390 USGS QUAD - GWINN (1975) RK0390 RK0390 *CURRENT SURVEY CONTROL RK0390 ___________________________________________________________________ RK0390* NAD 83(1986)- 46 18 18. (N) 087 22 37. (W) SCALED RK0390* NAVD 88 - 349.476 (meters) 1146.57 (feet) ADJUSTED RK0390 ___________________________________________________________________ RK0390 GEOID HEIGHT- -34.42 (meters) GEOID03 RK0390 DYNAMIC HT - 349.487 (meters) 1146.61 (feet) COMP RK0390 MODELED GRAV- 980,635.7 (mgal) NAVD 88 RK0390 RK0390 VERT ORDER - FIRST CLASS 0 RK0390 RK0390.The horizontal coordinates were scaled from a topographic map and have RK0390.an estimated accuracy of +/- 6 seconds. RK0390 RK0390.The orthometric height was determined by differential leveling RK0390.and adjusted by the National Geodetic Survey in June 1991. RK0390 RK0390.The geoid height was determined by GEOID03. RK0390 RK0390.The dynamic height is computed by dividing the NAVD 88 RK0390.geopotential number by the normal gravity value computed on the RK0390.Geodetic Reference System of 1980 (GRS 80) ellipsoid at 45 RK0390.degrees latitude (g = 980.6199 gals.). RK0390 RK0390.The modeled gravity was interpolated from observed gravity values. RK0390 RK0390; North East Units Estimated Accuracy RK0390;SPC MI N - 169,190. 7,970,960. MT (+/- 180 meters Scaled) RK0390 RK0390 SUPERSEDED SURVEY CONTROL RK0390 RK0390.No superseded survey control is available for this station. RK0390_U.S. NATIONAL GRID SPATIAL ADDRESS: 16TDS709280(NAD 83) RK0390_MARKER: I = METAL ROD RK0390_SETTING: 46 = COPPER-CLAD STEEL ROD W/O SLEEVE (10 FT.+) RK0390_SP_SET: COPPER-CLAD STEEL ROD RK0390_PROJECTION: RECESSED 25 CENTIMETERS RK0390_STABILITY: B = PROBABLY HOLD POSITION/ELEVATION WELL RK0390_SATELLITE: THE SITE LOCATION WAS REPORTED AS SUITABLE FOR RK0390+SATELLITE: SATELLITE OBSERVATIONS - May 25, 2000 RK0390_ROD/PIPE-DEPTH: 7.62 meters RK0390 RK0390 HISTORY - Date Condition Report By RK0390 HISTORY - 1975 MONUMENTED NOS RK0390 HISTORY - 20000525 GOOD MIDT RK0390 HISTORY - 20041101 GOOD USPSQD RK0390 RK0390 STATION DESCRIPTION RK0390 RK0390'DESCRIBED BY NATIONAL OCEAN SERVICE 1975 RK0390'2.25 MI NW FROM LITTLE LAKE. RK0390'2.25 MILES NORTHWEST ALONG THE CHICAGO AND NORTHWESTERN RAILROAD RK0390'FROM THE STATION AT LITTLE LAKE, 2.1 MILE NORTHWEST OF CO. RD. RK0390'456, AT SWANZY LAKE RD. 97 FT. SOUTHWEST OF CENTERLINE OF TRACK, RK0390'25.5 FT. NORTHWEST CENTERLINE OF SWANZY LAKE RD., 4.7 FT. WEST OF RK0390'UTILITY POLE NUMBER 4116, 10 INCHES BELOW GROUND SURFACE. RK0390 RK0390 STATION RECOVERY (2000) RK0390 RK0390'RECOVERY NOTE BY MICHIGAN DEPARTMENT OF TRANSPORTATION 2000 (MPR) RK0390'FROM JUNCTION OF HWY'S M35 AND M553 GO 1 MI -E- ALONG HWY 35, THENCE 2 RK0390'MILE -N- ALONG MARSHALL DR (FORMALLY 553), THENCE 0.8 MI -NE- ALONG RK0390'(GRAVEL) SWANZY LAKE RD TO RAILROAD AND MARK ON LEFT. 97 FT -S- OF RK0390'C/L RR, 59.4 GT -W- OF GAS LINE MARKER, 4.6 FT -W- OF CUTOFF POLE, 1 RK0390'FT -W- OF WITNESS POST, 0.8 FT BELOW GROUND ENCASSED IN CONCRETE PIPE. RK0390'

Aren't you glad I asked??!!?? Geographic Centers NETSTATE provides coordinates and location descriptions that are intended to pinpoint the "geographic center" of each of the States of the United States. This information is/was obtained from the United States Geologic Survey (USGS). We have received numerous questions regarding this information including complaints that the coordinates don't align with the location descriptions. In response to the questions we have received, we contacted the USGS. Essentially, we have tried to get information about the methodology used to calculate the coordinates and the location descriptions. We have been unsuccessful. The USGS has taken the position that the source for this information is unknown and that there is no official definition for a geographic center and, therefore, no official methodology for determining a geographic center. The USGS has removed virtually all of coordinate information that they provided online, but they still maintain a list of location descriptions. The following was quoted from the USGS web site on November 6, 2007: Because there is no generally accepted definition of a geographic center and no completely satisfactory method of determining it, there may be as many geographic centers of a State or county as there are definitions of the term. The geographic center of an area may be defined as the center of gravity of the surface, or that point on which the surface of an area would balance if it were a plane of uniform thickness. Curvature of the Earth, large bodies of water, irregular surfaces, and other factors affect the determination of center of gravity. In determining the centers of the States, islands adjacent to their coastlines and large bodies of water were excluded. The geographic centers and positions listed below should be considered as approximations. NOTE: "Positions" noted in the last sentence above have been removed (except for Alaska) from the information provided in the USGS Geographic Centers table. Sources The United States Geological Survey, "Elevations and Distances in the United States: Geographic Centers", 29 April 2005, <http://erg.usgs.gov/isb/pubs/booklets/elvadist/elvadist.html#Geographic%20Centers> (6 November 2007) Now, on to the geographic center of the US: No marked or monumented point has been established by any government agency as the geographic center of either the 50 States, the conterminous United States, or the North American continent. However, a monument was erected in Lebanon, Kansas, by a group of citizens who hired engineers to determine the position of the "geographic center" of the United States. Sometimes confused with geographic center of the United States is the triangulation station "Meades Ranch," located at latitude 39°13'26.686" North and longitude 98°32'30.506" West, about 12 miles north of Lucas, Kansas. This was the primary reference point for the North American Datum of 1927, the standard on which all the latitude and longitude lines for North America were based. This datum is being replaced by the North American Datum of 1983, which is not hinged to a single point of reference.

If you use the NGS datasheets (e.g., the county downloads) and run it through bmgpx.exe, you get something like this for each PID: <wpt lat="41.072778" lon="-74.962778"> <time>1942-01-01T00:00:00Z</time> <name>LY0748</name> <desc>Z 33</desc> <url>http://www.geocaching.com/mark/details.asp?PID=LY0748</url> <urlname>Z 33</urlname> <sym>Geocache</sym> <type>Geocache</type> <Groundspeak:cache id="-3100748" available="True" archived="False" xmlns:Groundspeak="http://www.Groundspeak.com/cache/1/0"> <Groundspeak:name>Z 33</Groundspeak:name> <Groundspeak:placed_by>CGS</Groundspeak:placed_by> <Groundspeak:owner id="0"></Groundspeak:owner> <Groundspeak:type>Unknown Cache</Groundspeak:type> <Groundspeak:container>Regular</Groundspeak:container> <Groundspeak:difficulty>1</Groundspeak:difficulty> <Groundspeak:terrain>1</Groundspeak:terrain> <Groundspeak:country>United States</Groundspeak:country> <Groundspeak:state>New Jersey</Groundspeak:state> <Groundspeak:short_description html="True">NGS Datasheet</Groundspeak:short_description> <Groundspeak:long_description html="True"> <h1>Z 33</h1> <b> PID </b> LY0748 <br> <b> STATE/COUNTY</b> NJ/WARREN <br> <b> USGS QUAD </b> FLATBROOKVILLE (1997) <br> <p> <h2>Current Survey Control</h2> <hr> <b> NAD 83(1986)</b> 41 04 22. (N) 074 57 46. (W) SCALED <br> <b> NAVD 88 </b> 200.526 (meters) 657.89 (feet) ADJUSTED <br> <hr> <b> GEOID HEIGHT</b> -32.88 (meters) GEOID03 <br> <b> DYNAMIC HT </b> 200.438 (meters) 657.60 (feet) COMP <br> <b> MODELED GRAV</b> 980,178.2 (mgal) NAVD 88 <br> <p> <b> VERT ORDER </b> SECOND CLASS 0 <br> <p>The horizontal coordinates were scaled from a topographic map and have an estimated accuracy of +/- 6 seconds. <p>The orthometric height was determined by differential leveling and adjusted by the National Geodetic Survey in June 1991. <p>The geoid height was determined by GEOID03. <p>The dynamic height is computed by dividing the NAVD 88 geopotential number by the normal gravity value computed on the Geodetic Reference System of 1980 (GRS 80) ellipsoid at 45 degrees latitude (g = 980.6199 gals.). <p>The modeled gravity was interpolated from observed gravity values. <p> <table border=1><tr><td> </td><td> North </td><td> East </td><td> Units</td><td> Estimated Accuracy</td></tr><tr><td>SPC NJ </td><td> 248,730. </td><td> 111,110. </td><td> MT</td><td> (+/- 180 meters Scaled)</td></tr> </table> <p> <h2>Superseded Survey Control</h2> <p> NGVD 29 (??/??/92) 200.715 (m) 658.51 (f) ADJ UNCH 2 0 <br> <p>Superseded values are not recommended for survey control. NGS no longer adjusts projects to the NAD 27 or NGVD 29 datums. See file dsdata.txt to determine how the superseded data were derived. <p> <h2>Marker Information</h2>U.S. NATIONAL GRID SPATIAL ADDRESS: 18TWL031468(NAD 83) <br>MARKER: DB = BENCH MARK DISK <br>SETTING: 80 = SET IN A BOULDER <br>STAMPING: Z 33 1942 <br>STABILITY: C = MAY HOLD, BUT OF TYPE COMMONLY SUBJECT TO <br>STABILITY: SURFACE MOTION <br> </table> <p> <h2>History</h2><table border=1><tr><td>Date </td><td>Condition </td><td>Report By</td></tr><tr><td>1942 </td><td>MONUMENTED </td><td>CGS</td></tr> </table> <p> <h2>STATION DESCRIPTION </h2> <p>DESCRIBED BY COAST AND GEODETIC SURVEY 1942 AT MILLBROOK. AT MILLBROOK, ABOUT 125 FEET SOUTH OF THE MILLBROOK INN, AT A CONCRETE BRIDGE. A STANDARD DISK, SET IN THE TOP OF THE NORTH END OF THE SOUTHWEST GUARD WALL, AND 9 FEET WEST OF THE CENTER LINE OF THE ROAD. LINE OF THE ROAD </Groundspeak:long_description> <Groundspeak:encoded_hints /> <Groundspeak:logs /> <Groundspeak:travelbugs /> </Groundspeak:cache> </wpt> Pretty sloppy formatting, but it should give you an idea of what info you've got there. Caution: if you take that .gpx file and import it into USAPhotoMaps (as I do), and then make any change — as for example by slightly moving one of the markers — most of that hash goes away and you get something a lot more manageable like the following: <wpt lat="38.860556" lon="-77.045000"> <name>AI7616</name> <desc>T 231 RESET</desc> <sym>Geocache</sym> </wpt> -ArtMan-

I agree the message system - contacting and adding other users as friends - is very clunky. The messages are pretty vital, IMO, regardless of whether this is perceived as a social activity or no. Messages help us to keep in contact with cache owners, report problems, etc. The Facebook thing...best way to go about this is to add it as an optional dimension in the profile. It shouldn't be integrated with geocaching.com in any manner. Users should be able to add social "contact" options, though, as they can on any other similar profile. And I'm sure that'll still rile up the 'ole anti-Facebook crowd here. You don't use Facebook? Good for you, would you like a cookie for defying the social norm?

Here's a fun way to search your county benchmark database using GSAK. Have you ever wondered how many rivets were set in your county? Or maybe rock cairns, or chiseled marks? It's quick and easy using the Search (filter). Click on Search at the top left of the main GSAK screen and select filter. In the box next to "Full text search" type "Marker: 'type of mark you want to search for' ". It will look list this example for rivets - "Marker: R = RIVET" but without the quotes. (Coconino county has 43 PIDs for rivets) "Marker: 57 = LOOKOUT TOWER" without the quotes will show the forest fire lookout towers that have PIDs. Just pick a type from the list and search. Have fun. John The list of benchmark types... 01 = LONE TREE 02 = CONSPICUOUS ROCK 03 = MOUNTAIN PEAK 04 = ROCK PINNACLE 05 = ROCK AWASH 11 = PILING 12 = DOLPHIN 13 = LIGHTHOUSE 14 = NAVIGATION LIGHT 15 = RANGE MARKER 16 = DAYBEACON 17 = FLAG TOWER 18 = SIGNAL MAST 21 = AIRPORT BEACON 22 = AIRWAY BEACON 25 = RADAR ANTENNA 26 = SPHERICAL RADOME 27 = RADIO RANGE MAST 28 = LORAN MAST 41 = ANTENNA MAST 42 = RADIO/TV MAST 43 = RADIO/TV TOWER 44 = MICROWAVE MAST 45 = MICROWAVE TOWER 51 = TANK 52 = STANDPIPE TANK 53 = ELEVATED TANK 54 = WATER TOWER 55 = TOWER 56 = SKELETON TOWER 57 = LOOKOUT TOWER 58 = CONTROL TOWER 61 = POLE 62 = FLAGPOLE 63 = STACK 64 = SILO 65 = GRAIN ELEVATOR 66 = WINDMILL 67 = OIL DERRICK 68 = COMMERCIAL SIGN 69 = REGULATORY SIGN 70 = MONUMENT 71 = BOUNDARY MONUMENT 72 = CAIRN 73 = LOOKOUT HOUSE 74 = LARGE CROSS 75 = BELFRY 81 = GABLE 82 = FINIAL 83 = FLAGSTAFF 84 = LIGHTNING ROD 85 = CHIMNEY 86 = CUPOLA 87 = DOME 88 = OBSERVATORY DOME 89 = SPIRE 90 = CHURCH SPIRE 91 = CHURCH CROSS 92 = ANTENNA ON ROOF 93 = MICROWAVE ANTENNA ON BUILDING 94 = ROOFTOP VENTILATOR 95 = ROOFTOP BLOCKHOUSE A = ALUMINUM MARKER B = BOLT C = CAP OF CAP-AND-BOLT PAIR DA = ASTRO MARKER (USUALLY A DISK) DB = BENCH MARK DISK DD = SURVEY DISK DE = TRAVERSE STATION DISK DG = GRAVITY STATION DISK DH = HORIZONTAL CONTROL DISK DJ = TIDAL STATION DISK DK = GRAVITY REFERENCE MARK DISK DM = MAGNETIC STATION DISK DO = NOT SPECIFIED OR SEE DESCRIPTION DP = BASE LINE PIER DQ = CALIBRATION BASE LINE DISK DR = REFERENCE MARK DISK DS = TRIANGULATION STATION DISK DT = TOPOGRAPHIC STATION DISK DU = BOUNDARY MARKER DV = VERTICAL CONTROL DISK DW = NOS HYDROGRAPHIC SURVEY DISK DZ = AZIMUTH MARK DISK E = EARTHENWARE POT F = FLANGE-ENCASED ROD G = GLASS BOTTLE H = DRILL HOLE I = METAL ROD J = EARTHENWARE JUG K = CLAY TILE PIPE L = ABSOLUTE GRAVITY STATION PLUG M = AMMO SHELL CASING N = NAIL O = CHISELED CIRCLE P = PIPE CAP Q = CHISELED SQUARE R = RIVET S = SPIKE T = CHISELED TRIANGLE U = CONCRETE POST V = STONE MONUMENT W = UNMONUMENTED X = CHISELED CROSS Y = DRILL HOLE IN BRICK Z = SEE DESCRIPTION

Here's a fun way to search your county benchmark database using GSAK. Have you ever wondered how many rivets were set in your county? Or maybe rock cairns, or chiseled marks? It's quick and easy using the Search (filter). Click on Search at the top left of the main GSAK screen and select filter. In the box next to "Full text search" type "Marker: 'type of mark you want to search for' ". It will look list this example for rivets - "Marker: R = RIVET" but without the quotes. (Coconino county has 43 PIDs for rivets) "Marker: 57 = LOOKOUT TOWER" without the quotes will show the forest fire lookout towers that have PIDs. Just pick a type from the list and search. Have fun. John The list of benchmark types... 01 = LONE TREE 02 = CONSPICUOUS ROCK 03 = MOUNTAIN PEAK 04 = ROCK PINNACLE 05 = ROCK AWASH 11 = PILING 12 = DOLPHIN 13 = LIGHTHOUSE 14 = NAVIGATION LIGHT 15 = RANGE MARKER 16 = DAYBEACON 17 = FLAG TOWER 18 = SIGNAL MAST 21 = AIRPORT BEACON 22 = AIRWAY BEACON 25 = RADAR ANTENNA 26 = SPHERICAL RADOME 27 = RADIO RANGE MAST 28 = LORAN MAST 41 = ANTENNA MAST 42 = RADIO/TV MAST 43 = RADIO/TV TOWER 44 = MICROWAVE MAST 45 = MICROWAVE TOWER 51 = TANK 52 = STANDPIPE TANK 53 = ELEVATED TANK 54 = WATER TOWER 55 = TOWER 56 = SKELETON TOWER 57 = LOOKOUT TOWER 58 = CONTROL TOWER 61 = POLE 62 = FLAGPOLE 63 = STACK 64 = SILO 65 = GRAIN ELEVATOR 66 = WINDMILL 67 = OIL DERRICK 68 = COMMERCIAL SIGN 69 = REGULATORY SIGN 70 = MONUMENT 71 = BOUNDARY MONUMENT 72 = CAIRN 73 = LOOKOUT HOUSE 74 = LARGE CROSS 75 = BELFRY 81 = GABLE 82 = FINIAL 83 = FLAGSTAFF 84 = LIGHTNING ROD 85 = CHIMNEY 86 = CUPOLA 87 = DOME 88 = OBSERVATORY DOME 89 = SPIRE 90 = CHURCH SPIRE 91 = CHURCH CROSS 92 = ANTENNA ON ROOF 93 = MICROWAVE ANTENNA ON BUILDING 94 = ROOFTOP VENTILATOR 95 = ROOFTOP BLOCKHOUSE A = ALUMINUM MARKER B = BOLT C = CAP OF CAP-AND-BOLT PAIR DA = ASTRO MARKER (USUALLY A DISK) DB = BENCH MARK DISK DD = SURVEY DISK DE = TRAVERSE STATION DISK DG = GRAVITY STATION DISK DH = HORIZONTAL CONTROL DISK DJ = TIDAL STATION DISK DK = GRAVITY REFERENCE MARK DISK DM = MAGNETIC STATION DISK DO = NOT SPECIFIED OR SEE DESCRIPTION DP = BASE LINE PIER DQ = CALIBRATION BASE LINE DISK DR = REFERENCE MARK DISK DS = TRIANGULATION STATION DISK DT = TOPOGRAPHIC STATION DISK DU = BOUNDARY MARKER DV = VERTICAL CONTROL DISK DW = NOS HYDROGRAPHIC SURVEY DISK DZ = AZIMUTH MARK DISK E = EARTHENWARE POT F = FLANGE-ENCASED ROD G = GLASS BOTTLE H = DRILL HOLE I = METAL ROD J = EARTHENWARE JUG K = CLAY TILE PIPE L = ABSOLUTE GRAVITY STATION PLUG M = AMMO SHELL CASING N = NAIL O = CHISELED CIRCLE P = PIPE CAP Q = CHISELED SQUARE R = RIVET S = SPIKE T = CHISELED TRIANGLE U = CONCRETE POST V = STONE MONUMENT W = UNMONUMENTED X = CHISELED CROSS Y = DRILL HOLE IN BRICK Z = SEE DESCRIPTION Duplicate post in the regular benchmark forum.

That's how I normally approach geocaching. Blind because my eyesight for reading is HORRIBLE. And I HATE glasses. So as I'm driving I am, most likely, the biggest threat on the highway. I'm juggling my sunglasses and reading glasses while balancing my GPS, (in my hand because the stupid window mount is worthless), and my Big Mac with a super-sized diet coke that will NOT fit into my cup holder. You don't want to meet me on the road. Other annoyances - forgoing the window mount that only mildly sucks I have to place my GPS on the dash for reception - which then dances from side to side and off the dash like Mary Lou Retton on uppers. When it comes to GPS's residing on dashes the ole' standby "For every action..."...needs to be changed to "For every action there is a disproportionately and completely 'ludicrous defying all physical laws' reaction". I've only been geocaching for about 3 or 4 months...and yet, in all that time, NOT ONCE have I ever guessed right and been in the right lane to turn off to the cache I'm seeking. And another AMAZING and defying all logical explanation law of geocaching - they are NEVER on the side of the Freeway you are traveling on. I have a cousin to whom NONE of the above applies. He's so incredibly efficient that he has never experienced ANY of my problems...he worked them all out. He reads manuals. He bought cup-holder adaptors to compensate. I hate his guts. - JamesJM

Unfortunately Not all Stations are Adjusted, so what you are saying is not correct. I said most are usually Adjusted... In your attempt to correct me, you are now in error. Case in point, the station 0.3 miles from the Station this thread is about, is NOT Adjusted. PP1414 DESIGNATION - 827 PP1414 PID - PP1414 PP1414 STATE/COUNTY- MN/HENNEPIN PP1414 USGS QUAD - ST PAUL WEST (1993) PP1414 PP1414 *CURRENT SURVEY CONTROL PP1414 ___________________________________________________________________ PP1414* NAD 83(1986)- 44 58 05. (N) 093 12 26. (W) SCALED PP1414* NAVD 88 - 277.234 (meters) 909.56 (feet) POSTED PP1414 ___________________________________________________________________ PP1414 GEOID HEIGHT- -27.16 (meters) GEOID99 PP1414 DYNAMIC HT - 277.230 (meters) 909.55 (feet) COMP PP1414 MODELED GRAV- 980,581.8 (mgal) NAVD 88 PP1414 PP1414 VERT ORDER - * POSTED, Code E , SEE BELOW PP1414 PP1414.The horizontal coordinates were scaled from a topographic map and have PP1414.an estimated accuracy of +/- 6 seconds. PP1414 PP1414.The orthometric height was determined by differential leveling PP1414.and adjusted by the National Geodetic Survey in 1992. PP1414.* This is a POSTED BENCH MARK height. Code E indicates a distribution PP1414.rate of 4.1 thru 8.0 mm/km. PP1414 PP1414.The geoid height was determined by GEOID99. PP1414 PP1414.The dynamic height is computed by dividing the NAVD 88 PP1414.geopotential number by the normal gravity value computed on the PP1414.Geodetic Reference System of 1980 (GRS 80) ellipsoid at 45 PP1414.degrees latitude (g = 980.6199 gals.). PP1414 PP1414.The modeled gravity was interpolated from observed gravity values. PP1414 PP1414; North East Units Estimated Accuracy PP1414;SPC MN S - 318,980. 862,540. MT (+/- 180 meters Scaled) PP1414 PP1414 SUPERSEDED SURVEY CONTROL PP1414 PP1414 NGVD 29 - 277.182 (m) 909.39 (f) ADJ UNCH 2 0 PP1414 PP1414.Superseded values are not recommended for survey control. PP1414.NGS no longer adjusts projects to the NAD 27 or NGVD 29 datums. PP1414.See file dsdata.txt to determine how the superseded data were derived. PP1414 PP1414_MARKER: DD = SURVEY DISK PP1414_SETTING: 0 = UNSPECIFIED SETTING PP1414_STAMPING: 827 PP1414_STABILITY: D = MARK OF QUESTIONABLE OR UNKNOWN STABILITY PP1414 PP1414 HISTORY - Date Condition Recov. By PP1414 HISTORY - UNK MONUMENTED PP1414 HISTORY - 1966 GOOD MNDT PP1414 HISTORY - 1987 GOOD USPSQD PP1414 PP1414 STATION DESCRIPTION PP1414 PP1414''DESCRIBED BY MN DEPT OF TRANSP 1966 PP1414''IN MINNEAPOLIS. PP1414''MARK IS LOCATED AT THE HENNEPIN - RAMSEY COUNTY LINE BETWEEN ST. PAUL PP1414''AND MINNEAPOLIS NEAR THE KSTP RADIO STATION, IN THE CENTERLINE OF PP1414''EMERALD STREET, IN LINE WITH THE SOUTH CURB OF UNIVERSITY AVENUE, PP1414''FLUSH WITH THE PAVEMENT. PP1414 PP1414 STATION RECOVERY (1987) PP1414 PP1414''RECOVERY NOTE BY US POWER SQUADRON 1987 (CAF) PP1414''RECOVERED IN GOOD CONDITION. Yup, Things sure can be complicated, sometimes. That is why it is important to be careful, Succinct, and Thorough in our attempts to give others accurate advice. Rob

Het valt mij op de reviewer Neon Tetra meerdere caches heeft gepubliceerd die op te korte afstand van een andere cache zijn verwijderd, binnen 161 meter, en soms zelfs slechts 25 meter. Kent deze reviewer de regels niet of kan me vooraf hem toestemming vragen? ik heb ook leuke locaties gevonden die ideaal zijn voor een leuke nano, maar op 100 meter ligt er al eentje van iemand anders, dus ik zou dat ook wel willen. (maar of het nou echt de bedoeling is om op elke hoek v.d. straat een cache te plaatsen vraag ik me af). Overigens; stel nou dat een reviewer een fout maakt, word een cache dan alsnog gearchiveerd of heeft de maker ervan gewoon mazzel gehad ? p.s. 'Geo-Gravity' ik ben ook caches tegengekomen die door jou zijn gepubliceerd en ook niet voldoen aan de regels, zoals GC49JZ3 Moord op de tennisbaan. Verdachte 1 , welke op te korte afstand van een andere cache ligt. Of geld de 161 meter regel niet voor Mystery caches? (daar zijn de guidelines niet helder over namelijk)

Ditto what mloser said. Some background in more detail: The list of data sheets includes four kinds: 1. True bench marks, i.e. vertical control marks having ADJUSTED elevation and typically loose coordinates. 2. Triangulation stations, having ADJUSTED coordinates and typically loose elevation. These were occupied with instruments to take sights to other points and are the most accurately known among the "classical" control points. 3. Intersection Stations such as spires, tanks, towers, and chimneys. These were not occupied, but were sighted upon, mostly as a check on the data for triangulation stations. This gave them pretty good coordinates, but not as well-checked as the triangulation stations. 4. More recently, stations measured by GPS. The horizontal is great and the vertical is not in the same measurement system as the classical bench marks. There are also a few older stations serving both horizontal and vertical purposes. Elevation bench marks are still of great importance, at least for the next several years until NGS puts out a new GPS and gravity-based vertical datum, and it is adopted by all users, including the national flood insurance program, the Corps of Engineers, and cities that haven't all moved even to the current datum. Triangulation stations are of decreasing importance due to widespread use of precision GPS, but still are of interest to NGS. Intersection stations are a.) less accurate, b.) often moved slightly over time by maintenance and nature, and c.) not readily occupied by GPS to allow future use, so NGS has pretty much given up on them. ---- The lack of intersection stations in your area could be due to you not having any stations of the triangulation network in your immediate vicinity. The elevation and coordinate surveys were essentially independent. Each network was a fishnet mesh stretched across the country and sometimes the holes were 20 miles or more wide. The networks generally don't coincide. The stations were chosen by different criteria. For vertical (elevation) work you want nice clear sight lines for 300 yard/meter increments, and as few hills as practical. Thus they frequently followed railroads and roads. For horizontal coordinates, you want to see as far as possible, from a Bilby tower if necessary, so stations were placed on the higher spots available and several miles apart.

quote:Originally posted by FullOn:One thing I've never been able to figure out... If aliens are so technologically advanced that they can travel across the galaxy, defying every law of physics that we know of, how come they can't build a craft that doesn't have exterior illumination on it? http://www.scgeocachers.org/ Well, in terms of "defying" the laws of physics, let's be sqaure on this: "who's" laws of physics? Ours or Theirs? Existing physical laws are being twisted inside out by Chaos Theory and Quantum Mechanics. As for external illumination of a spacecraft, perhaps illumination is the last thing anyone visiting this rock would want, given our military's penchant for shooting at anything that doesn't have a radar transponder spewing forth aviation ident codes. Another aspect of the whole space travel thing is what is space, really? certainly rocketry isn't going to get us there. Some type of curving of space/time will be necessary, I think, for the distances we need to travel in negligible time. Existence, itself, is even taking on the appearance of something more akin to a projected dream/state than anything else. I don't stick to the old physical paradigms. There's just too much evidence to the contrary. Warm regards, Firefishe --------------------------- The year is 2003. The name is S.A. Brown. BrowNAV (Brown Navigation) ---------------------------

Piece o' cake. You need a program called BMGPX, which you can download from Ron Parker's "Fuzzy's Geocaching Page o' Wonders". This very small program (zip download is only 12K) will extract the needed information from a DAT file and format it as a GPX file. DAT files can be downloaded for any county in the country from the NGS website. Easiest way to use it is to unzip the download, then drop-n-drag a DAT file onto BMGPX.EXE. In a few seconds you'll have a GPX file to be imported into USAPhotoMaps. The GPX file will be quite large because each PID will have a lot of imported data fields. Here's an ArtMan hint: once you have your benchmarks displayed in USAPhotoMaps, move one of the dots slightly — perhaps to slide a mark to coincide with the representation on the map. Once you make a change, USAPhotoMaps will rewrite the GPX file, but it will strip away all the unneeded fields an leave you with a lean, quick-loading file. Example, using Charlottesville city, VA The DAT file is 57K The GPX file is 85K The GPX file is 3K after unneeded fields are deleted, as described above. What unneeded fields? Here's an original GPX entry for one PID in RED, followed by the stripped-down version in GREEN: <wpt lat="38.028611" lon="-78.476944"> <time>2005-04-22T22:58:10Z</time> <name>HW0449</name> <desc>455.68</desc> <url>http://www.geocaching.com/mark/details.asp?PID=HW0449</url> <urlname>455.68</urlname> <sym>Geocache</sym> <type>Geocache</type> <Groundspeak:cache id="-2040449" available="True" archived="False" xmlns:Groundspeak="http://www.Groundspeak.com/cache/1/0"> <Groundspeak:name>455.68</Groundspeak:name> <Groundspeak:placed_by>USGS</Groundspeak:placed_by> <Groundspeak:owner id="0"></Groundspeak:owner> <Groundspeak:type>Unknown Cache</Groundspeak:type> <Groundspeak:container>Regular</Groundspeak:container> <Groundspeak:difficulty>1</Groundspeak:difficulty> <Groundspeak:terrain>1</Groundspeak:terrain> <Groundspeak:country>United States</Groundspeak:country> <Groundspeak:state>Virginia</Groundspeak:state> <Groundspeak:short_description html="True">NGS Datasheet</Groundspeak:short_description> <Groundspeak:long_description html="True"> <h1>455.68</h1> <b> PID </b> HW0449 <br> <b> STATE/COUNTY</b> VA/C OF CHARLOTTESVILLE <br> <b> USGS QUAD </b> CHARLOTTESVILLE EAST (1997) <br> <p> <h2>Current Survey Control</h2> <hr> <b> NAD 83(1986)</b> 38 01 43. (N) 078 28 37. (W) SCALED <br> <b> NAVD 88 </b> 138.608 (meters) 454.75 (feet) ADJUSTED <br> <hr> <b> GEOID HEIGHT</b> -32.53 (meters) GEOID03 <br> <b> DYNAMIC HT </b> 138.512 (meters) 454.43 (feet) COMP <br> <b> MODELED GRAV</b> 979,937.8 (mgal) NAVD 88 <br> <p> <b> VERT ORDER </b> SECOND CLASS 0 <br> <p>The horizontal coordinates were scaled from a topographic map and have an estimated accuracy of +/- 6 seconds. <p>The orthometric height was determined by differential leveling and adjusted by the National Geodetic Survey in June 1991. <p>The geoid height was determined by GEOID03. <p>The dynamic height is computed by dividing the NAVD 88 geopotential number by the normal gravity value computed on the Geodetic Reference System of 1980 (GRS 80) ellipsoid at 45 degrees latitude (g = 980.6199 gals.). <p>The modeled gravity was interpolated from observed gravity values. <p> <table border=1><tr><td> </td><td> North </td><td> East </td><td> Units</td><td> Estimated Accuracy</td></tr><tr><td>SPC VA S </td><td> 1,188,140. </td><td> 3,502,020. </td><td> MT</td><td> (+/- 180 meters Scaled)</td></tr> </table> <p> <h2>Superseded Survey Control</h2> <p> NGVD 29 (??/??/92) 138.851 (m) 455.55 (f) ADJ UNCH 2 0 <br> <p>Superseded values are not recommended for survey control. NGS no longer adjusts projects to the NAD 27 or NGVD 29 datums. See file dsdata.txt to determine how the superseded data were derived. <p> <h2>Marker Information</h2>U.S. NATIONAL GRID SPATIAL ADDRESS: 17SQC214119(NAD 83) <br>MARKER: Q = CHISELED SQUARE <br>SETTING: 30 = COPING <br>STABILITY: D = MARK OF QUESTIONABLE OR UNKNOWN STABILITY <br> </table> <p> <h2>History</h2><table border=1><tr><td>Date </td><td>Condition </td><td>Report By</td></tr><tr><td>UNK </td><td>MONUMENTED </td><td>USGS</td></tr><tr><td>1935 </td><td>GOOD </td><td>NGS</td></tr> </table> <p> <h2>STATION DESCRIPTION </h2> <p>DESCRIBED BY NATIONAL GEODETIC SURVEY 1935 AT CHARLOTTESVILLE. AT CHARLOTTESVILLE, ALBEMARLE COUNTY, ABOUT 300 FEET SOUTHEAST OF THE CHESAPEAKE AND OHIO RAILWAY STATION, AT THE SOUTH END OF THE CROSSING OF THE LONG STATE HIGHWAY 239 BRIDGE, ON THE TOP OF THE EAST CONCRETE COPING OF THE APPROACH, AND 1.5 FEET FROM THE SOUTH END. A CHISELED SQUARE. </Groundspeak:long_description> <Groundspeak:encoded_hints /> <Groundspeak:logs /> <Groundspeak:travelbugs /> </Groundspeak:cache> </wpt> <wpt lat="38.028611" lon="-78.476944"> <name>HW0449</name> <desc>455.68</desc> <sym>Geocache</sym> </wpt> Here's the text of the Readme file — The purpose of this program is to convert the .dat files available from the National Geodetic Survey to GPX files that can be read by the many free programs that are available to geocachers. This program is a command-line program, so you should be familiar with the command prompt. *** TO INSTALL: Just put the file bmgpx.exe somewhere in your path. *** TO USE: Before using this program, you need a .dat file. To get a .dat file, use your web browser to go to http://www.ngs.noaa.gov/cgi-bin/datasheet.prl , click on the "ARCHIVED DATASHEETS" button, then click on the "YEARLY_ARCHIVES" button. Select your state and click "GET COUNTY ARCHIVES". Select the county you want and in what format you want to receive the data, then click the "Download File" button. When you have the file, uncompress it if necessary. Now you're ready to use bmgpx. If I've downloaded the .dat file for Allen County, Indiana, I would type this: bmgpx in003.dat allen_bm.gpx in003.dat is the name of the .dat file I downloaded from the NGS website. allen_bm.gpx could be any name, but I chose one that tells me what's in the file. Now I can use allen_bm.gpx with EasyGPS, GPSBabel, Watcher, or any other program that can work with gpx files. For more detailed usage information, including hints on usage with Unix pipes, type "bmgpx -h" Starting with version 1.06, bmgpx will automatically generate an output filename from the input filename if you provide only the input filename. Previous versions would write the output to standard output. If you were counting on the old behavior, you'll have to use shell redirection to achieve the desired result: bmgpx <in003.dat This change allows bmgpx to be used as a drop target. Just drag a .dat file and drop it on the bmgpx icon and it'll automatically generate a .gpx file in the directory where the .dat file is.

Yes! We have em, there called CGSN or Canadian gravity standardization network, stations. I have located three in my area through this site and I will check them out with my gps. They should work exactly like a Benchmark. Thank you tons spud67 One thing about the gravity network BM's is that the coordinates are often scaled off maps not surveyed (check the description of the BM) so you can't check the accuracy of your GPSr against them. Gravity measurements are accurate however.

It appears someone reset the mark and it was downgraded to vertical only. Since the mark was a horizontal mark to begin with, that was what they used to reset that mark but for some reason NGS would not puiblish the horizontal position. Many times these reset marks are done locally using sub-standard equipment and procedures that iits intergrity is now questionable. I know its indicates NGS but it may not have been NGS that did the work, it may have been done locally and sent to NGS. Any mark that is not tied to other marks will always be of questionable position because it cannot be verified. The NGS Data Sheet See file dsdata.txt for more information about the datasheet. DATABASE = Sybase ,PROGRAM = datasheet, VERSION = 7.16 *** NOTE - The station below is destroyed. 1 National Geodetic Survey, Retrieval Date = APRIL 10, 2005 HV2273 *********************************************************************** HV2273 DESIGNATION - PIMMIT HV2273 PID - HV2273 HV2273 STATE/COUNTY- VA/FAIRFAX HV2273 USGS QUAD - FALLS CHURCH (1994) HV2273 HV2273 *CURRENT SURVEY CONTROL HV2273 ___________________________________________________________________ HV2273* NAD 83(1993)- 38 54 31.97825(N) 077 12 47.31193(W) ADJUSTED HV2273* NAVD 88 - 150.569 (meters) 493.99 (feet) ADJUSTED HV2273 ___________________________________________________________________ HV2273 LAPLACE CORR- -1.87 (seconds) DEFLEC99 HV2273 GEOID HEIGHT- -31.77 (meters) GEOID03 HV2273 DYNAMIC HT - 150.486 (meters) 493.72 (feet) COMP HV2273 MODELED GRAV- 980,074.3 (mgal) NAVD 88 HV2273 HV2273 HORZ ORDER - SECOND HV2273 VERT ORDER - SECOND CLASS 0 HV2273 HV2273.The horizontal coordinates were established by classical geodetic methods HV2273.and adjusted by the National Geodetic Survey in November 1994. HV2273 HV2273.The orthometric height was determined by differential leveling HV2273.and adjusted by the National Geodetic Survey in June 1991. HV2273 HV2273.The Laplace correction was computed from DEFLEC99 derived deflections. HV2273 HV2273.The geoid height was determined by GEOID03. HV2273 HV2273.The dynamic height is computed by dividing the NAVD 88 HV2273.geopotential number by the normal gravity value computed on the HV2273.Geodetic Reference System of 1980 (GRS 80) ellipsoid at 45 HV2273.degrees latitude (g = 980.6199 gals.). HV2273 HV2273.The modeled gravity was interpolated from observed gravity values. HV2273 HV2273; North East Units Scale Factor Converg. HV2273;SPC VA N - 2,138,668.507 3,611,610.721 MT 0.99996128 +0 48 11.3 HV2273;UTM 18 - 4,308,993.704 308,104.409 MT 1.00005346 -1 23 25.7 HV2273 HV2273! - Elev Factor x Scale Factor = Combined Factor HV2273!SPC VA N - 0.99998136 x 0.99996128 = 0.99994264 HV2273!UTM 18 - 0.99998136 x 1.00005346 = 1.00003482 HV2273 HV2273: Primary Azimuth Mark Grid Az HV2273:SPC VA N - POPLAR 153 11 56.4 HV2273:UTM 18 - POPLAR 155 23 33.4 HV2273 HV2273|---------------------------------------------------------------------| HV2273| PID Reference Object Distance Geod. Az | HV2273| dddmmss.s | HV2273| DC7041 PIMMIT RM 1 39.944 METERS 02219 | HV2273| HV4807 ARLINGTON RAD STA WAVA MAST APPROX. 7.0 KM 1015747.1 | HV2273| HV4805 ARLINGTON ATT MICROWAVE APPROX. 6.9 KM 1020453.5 | HV2273| HV4808 ARLINGTON TV WTTG TOWER APPROX. 7.3 KM 1050453.1 | HV2273| HV2269 POPLAR APPROX. 2.6 KM 1540007.7 | HV2273| HV4814 FALLS CH RAD STA WOL TOWER APPROX. 2.7 KM 1553751.0 | HV2273| HV2272 PIMMIT RM 2 27.210 METERS 29137 | HV2273|---------------------------------------------------------------------| HV2273 HV2273 SUPERSEDED SURVEY CONTROL HV2273 HV2273 NAD 83(1993)- 38 54 31.97719(N) 077 12 47.31441(W) AD( ) 2 HV2273 NAD 83(1986)- 38 54 31.97709(N) 077 12 47.32400(W) AD( ) 2 HV2273 NAD 27 - 38 54 31.57621(N) 077 12 48.38514(W) AD( ) 2 HV2273 NGVD 29 (??/??/??) 150.790 (m) 494.72 (f) ADJUSTED 2 0 HV2273 HV2273.Superseded values are not recommended for survey control. HV2273.NGS no longer adjusts projects to the NAD 27 or NGVD 29 datums. HV2273.See file dsdata.txt to determine how the superseded data were derived. HV2273 HV2273_U.S. NATIONAL GRID SPATIAL ADDRESS: 18SUJ0810408994(NAD 83) HV2273_MARKER: DS = TRIANGULATION STATION DISK HV2273_SETTING: 7 = SET IN TOP OF CONCRETE MONUMENT HV2273_SP_SET: SET IN TOP OF CONCRETE MONUMENT HV2273_STAMPING: PIMMIT 1958 HV2273_MAGNETIC: N = NO MAGNETIC MATERIAL HV2273_STABILITY: C = MAY HOLD, BUT OF TYPE COMMONLY SUBJECT TO HV2273+STABILITY: SURFACE MOTION HV2273 HV2273 HISTORY - Date Condition Report By HV2273 HISTORY - 1958 MONUMENTED CGS HV2273 HISTORY - 1960 GOOD CGS HV2273 HISTORY - 1979 DESTROYED NGS HV2273 HV2273 STATION DESCRIPTION HV2273 HV2273'DESCRIBED BY COAST AND GEODETIC SURVEY 1958 (JCE) HV2273'STATION IS LOCATED ABOUT 2.9 MILES NORTHWEST OF FALLS CHURCH, HV2273'1.15 MILES SOUTHEAST OF TYSONS CROSSROADS AND ABOUT 250 FEET HV2273'NORTHEAST OF STATE HIGHWAY NO. 7 (LEESBURG TURNPIKE). 40-1/2 HV2273'FEET WEST-NORTHWEST OF THE NORTHWEST SIDE OF PIMMIT SERVICE HV2273'COMPANY WATER STANDPIPE, 22-1/2 FEET NORTH-NORTHEAST OF HV2273'FENCELINE, AND 35-1/2 FEET EAST-NORTHEAST OF FENCE CORNER. THE HV2273'MARK IS SET FLUSH AND THE DISK IS STAMPED, PIMMIT 1958. HV2273' HV2273'REFERENCE MARK NO. 1 IS 3 FEET EAST-SOUTHEAST OF A LOCUST TREE, HV2273'AND 36 FEET SOUTH-SOUTHWEST OF A PERSIMMON TREE. THE MARK IS HV2273'SET FLUSH AND THE DISK IS STAMPED, PIMMIT R.M. NO 1 1958. HV2273' HV2273'REFERENCE MARK NO. 2 IS 1 FOOT SOUTHEAST OF POWERLINE POLE, HV2273'1 FOOT NORTHEAST OF FENCE CORNER, AND 10 FEET SOUTH-SOUTHEAST HV2273'OF THE CENTERLINE OF ALLEY. THE MARK IS SET FLUSH AND THE HV2273'DISK IS STAMPED PIMMIT R.M. NO 2 1958. HV2273' HV2273'TO REACH THE STATION FROM THE JUNCTION OF STATE HIGHWAY NO. HV2273'123 AND STATE HIGHWAY NO. 7 AT TYSONS CROSSROADS, GO SOUTHEAST ON HV2273'STATE HIGHWAY NO. 7 FOR 1.15 MILE TO LISLE AVENUE TO THE LEFT, HV2273'TURN LEFT THENCE RIGHT ON STREET WHICH PARALLELS STATE HIGHWAY HV2273'NO. 7 AND GO ABOUT 100 YARDS, TURN LEFT OVER CURBING (PURPOSED HV2273'ALLEY). AND GO NORTHERLY PASSING BETWEEN HOUSES NUMBERED HV2273'2408 AND 2410 AND GO 25 YARDS, THENCE RIGHT ABOUT 100 FEET HV2273'AND STATION AS DESCRIBED. HV2273' HV2273'NO SUITABLE PLACE WAS FOUND TO SET AN AZIMUTH MARK. AND THERE HV2273'ISNT ANYTHING VISIBLE FROM GROUND. HV2273' HV2273'HEIGHT OF LIGHT ABOVE STATION MARK 27 METERS. HV2273 HV2273 STATION RECOVERY (1960) HV2273 HV2273'RECOVERY NOTE BY COAST AND GEODETIC SURVEY 1960 HV2273'1.4 MI NE FROM DUNN LORING. HV2273'ABOUT 1.0 MILE NORTH ALONG DUNN LORING ROAD FROM THE POST HV2273'OFFICE AT DUNN LORING, THENCE ABOUT 0.45 MILE SOUTHEAST ALONG HV2273'STATE HIGHWAY 7, ABOUT 100 YARDS NORTHEAST OF HIGHWAY 7, 40 1/2 HV2273'FEET WEST-NORTHWEST OF THE NORTHWEST SIDE OF PIMMIT SERVICE HV2273'COMPANY WATER STANDPIPE, 22 1/2 FEET NORTH-NORTHEAST OF FENCE HV2273'LINE, 35 1/2 FEET EAST-NORTHEAST OF A FENCE CORNER, 89.3 FEET HV2273'SOUTHEAST OF R M 2, AND SET IN TOP OF A CONCRETE POST FLUSH WITH HV2273'THE GROUND. HV2273 HV2273 STATION RECOVERY (1979) HV2273 HV2273'RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1979 (CLN) HV2273'STATION MARK RECOVERED WITH ONLY THE STEM OF THE DISK HV2273'REMAINING. REFERENCE MARK 1 AND REFERENCE MARK 2 RECOVERED IN GOOD HV2273'CONDITION. A NEW SURFACE DISK WAS SET. A SHORTER DISTANCE OF 0.19 HV2273'FEET WAS NOTED TO RM 1 AND 0.04 FEET TO RM 2. THE ANGLE BETWEEN HV2273'MARKS CHECKED WITH 1958 DATA. *** retrieval complete. Elapsed Time = 00:00:00

For at least the next 10 years, elevation benchmarks will provide more accurate elevations than can be obtained by GPS. Although GPS can get a height above the ellipsiod, that requires knowledge of the geoid (determined by the local strength of gravity) to convert into "orthometric height" which is what is obtained by optical leveling and is important for construction/drainage work. Until NGS collects a lot more gravity data, they can't make the conversion accurately enough for some purposes.

Okay, did ANYone else but me see a red-eyed, time-traveling android with a chrome-plated skeleton when he said T1, or is that just me? Back on topic, the 528 ft rule is kind of like the "gravity" rule: you can jump all you want, but no matter what, ole Mr. Gravity ain't gonna let ya stay up there. One way or another (and usually, it's pretty dern quick), you're comin' back down. I DO, however, think the Mystery/Unknown cache with a VIRTUAL stage (reference point stage), in which information must be gathered from text AT the theater that leads to the Physical cache's Final stage, is a really good bet for you. In fact, it's probably BETTER, because I know when I go caching, I often don't even see the businesses and building around me. I'm all about finding that smiley and seeing pretty nature. BUT if I'm FORCED to READ something AT a site, I'm far more likely to positively engage with whatever landmark involves the Reference Point stage. If you do this, it's completely within the guidelines and pretty much gives you what you want. My BEST piece of advice though: find at LEAST 200 caches before you do your first hide. And, if you DO hide a mystery cache, try to find around 2-5 before you ever make one yourself. By then, you'll have a much fuller knowledge of what makes a good cache hide, what locations attract the least amount of muggle attention, what locations are most rain/flood proof, and what containers need the least maintenance. Many containers (i.e. Butter tubs), after all, are a horrible idea, and that's just something you learn with more experience.

Een geocache zal nooit uit het archief worden gehaald om ter adoptie te worden aangeboden. Geo Gravity Volunteer Reviewer voor Vlaanderen

Add 24 foot long pole with hook on end( painters pole 8 foot three sections) UV flashlight, hacksaw blade, Anti gravity boots In general anything that you can dream up. There have been a few times I wish for them boots. The insanely high 40 foot micro in a pine tree.

Mike and Linda, I stumbled across my first benchmark in early 1962. It was (and still is, I believe) located in the top of a railroad bridge abutment a few hundred meters from my home. It was a true "benchmark" as it had an elevation listed. During my next trip to the public library I read as much information as I could find about these objects. I was fascinated by the idea that precise location and elevation amsl could be determined by scientific instruments. I regard that discovery as one of several events in my young life that led me to a career in science. Over the years I have delighted in the occasional chance discoveries of benchmarks. The relatively recent availability of searchable databases/digital tools like the National Geodetic Survey Data Explorer and the Groundspeak listing have made hunting these structures much more practical. I even have an app on my smartphone now! In the last few years I have read much more of the literature that is available on the history of these marks (I was fascinated to learn that the reason that so many of the controls in my area were monumented in the 1930's was due to public works projects intended to keep surveyors and related personnel employed during the Great Depression.) I have also discovered that there are many purposes for what we commonly call benchmarks (I found a magnetic control this year and I hope to find a gravity station in 2015.) Science, history and interesting objects...what more could you ask for? Mike P.S.If you do go hunting benchmarks, take the kids.

Is there a GEODESIST in the house?? Okay, I guess I'll have to answer instead ... hold on to your hats. The "elevation" figure in your GPS (assuming it doesn't have a barometric altimeter - one that measures air pressure) is computed from the satellites' signals, just as is your latitude/longitude (or military grid) position. It's not really "altitude," but rather your height above (or below) the surface of the geodetic datum - an ellipsoidal surface that's the closest match that a semi-famous mathematician (like Clarke) could figure to the ruthlessly-measured positions and altitudes of several thousand "triangulation stations" across a country or continent. Problem is, these datums could only be fitted together by line-of-sight, using superbly machined optical instruments by the very best of precision-optical manufacturers, such as Leica and WILD Heerbrugge ... back in the days when surveyors were known in the mapping realm as "the WILD bunch." ") They fit their target regions well, but often they could NOT be resolved with others ... example, the infamous Tokyo datum, or the Provisional South American Datum of 1956. That all started to change with the first Sputnik. A satellite's orbital characteristics depend on the mass it's circling ... as does the ballistic trajectory of a long-range missile. If you want to hit the pickle barrel from 5000 miles away, you have to know not only exactly where the pickle barrel is, but exactly where YOU are in relation to the pickle barrel, and exactly what the Earth's not-so-uniform gravity field will do to bend or twist the path your missle needs to take. (I warned you!) Somebody else in the DoD got the brilliant idea that satellites could be used for navigation ... this was WELL before GPS; I'm talking the "Transit" birds of the 1960s. Years of observation of their orbits and their changes led to the World Geodetic System of 1972 (WGS 72) - the first "geocentric" datum, that is, the first one based on the size, shape and center-or-gravity of the Earth as a whole. A dozen more years of refining this model led to the WGS-84 datum we all know and love. The WGS datums are the best average fit to the entire world ... but they cannot be an exact fit to sea level in all parts of the world. Gravity fluctuates ... some regions of the world are denser than others. Those changes affect the surface we know as "mean sea level" - or what geodesists and the geodetically-afflicted call the "geoid". So it's actually higher than the surface of the WGS 84 ellipsoid (a smooth mathematical model) in some areas, lower in others. The professional term for this is "geoidal undulation," and it's a real problem for those national and international agencies that are trying to develop instrument-flight GPS approaches to the world's airports. When you're standing on the seashore and your GPS says you're significantly above MSL ... or significantly BELOW ... it's that "geoidal undulation" that's causing the confusion. (Of couse that doesn't include the extra confusion I've added... If you REALLY want to know more, the National Geodetic Survey has the book "Geodesy For The Layman" at http://www.ngs.noaa.gov/PUBS_LIB/Geodesy4Layman/toc.htm And if you want to know MORE, take two aspirin and lie down until the urge leaves you. (I have to know this professionally. It's not a fetish.)

Even though it may be taking the game too seriously, the cache should always be replaced as found. I enjoy the challenge of high terrain caches, and on more than one occasion I went out to look for a tree climb cache only to be disappointed to find it at eye level or on the ground under a pile of sticks. It's the same feeling I get when I'm watching a good movie on tv and the ending gets preempted by a 'breaking news' announcement, or buying a newspaper and finding that someone thoughtfully 'borrowed' it, did the puzzles, clipped a few things, and put it back on the rack. On the other hand, a cache owner who hides a cache up in a tree like that should secure it so that it cannot be knocked out of the tree. It is not that difficult to create a tether or clamp that will hold a cache in place without damaging the tree. And it helps to hide the cache high enough that a stick isn't going to knock it out of place. When I find a tree cache that is obviously out of place, I try to put it back where it should have been if at all possible. I check cache description and logs for how high, look for pictures, look for obvious clues like a loose tether. Failing that, the cache is liable to end up even higher than the original placement. I got a late start in tree climbing because my Mother was very protective, but to her dismay, once I got into trees I climbed everything I could. I climbed well into my teens, and slowly tapered off from there. I don't climb anymore just for the joy of it. It isn't fear of heights that did me in, but an aversion to gravity.

Casey and Geo, First Casey, you made the point that 1920 era datum were erroneous based on how they handle tidal uniformity. You are correct! But given what we knew at the time, it was a good system, and served a helpful purpose. Tides are not uniform as to height and timing at any two places along our coasts. It is a science in and unto itself as to how the times and height of the actual sea water levels are calculated. There are a lot of sources out there attempting to explain this concept. Factor in weather and there is more room for error. Geodetically speaking today, the term Mean Sea Level is a theoretical surface based on a single monument, it is not a component of the actual tidal waters, nor based on an 18-19 year average of all high and low tides at any one or 26 given locations. Nor is the reference standard for this Mean Sea Level based on how much water is in the ocean. (It could be based on this if you are a researcher studying how much water IS in the ocean!) These things are simply not a stable reference for geodetic purposes but some sources will attempt to define it this way. However NGVD 29, the old 1920's Datum was Sea Level based but averaged and computed based on twenty-one tidal stations in the US and five in Canada. 26 different, simultaneously adjusted stations. Tide was however affected by gravity too, and this system could not easily compensate for this because of the instability in the model. Taken together with older models, which define the Geoid, the Ellipsoid, actually thought to be a spheroid then, and other frames of reference, were based on the observations of the time. We really did the best we could with what we had and comparatively; we did pretty well at that! Mean Sea Level was not the same across the US as a belief, but rather made that way for the sake of mathematical reference. Today we use a different standard for Mean Sea Level yet we refer to it in the old way. You can google this definition and you will find many explanations as to what Mean Sea Level is. To be fair, I would say that many who have attempted to explain what mean sea level is, but most definitions seem to explain it in a way we no longer frame the reference. I have to smile upon them for trying. I sometimes wish we would call it something else today but it is what it is, confusion and all. For Geodetic purposes today these Datum are earth centered, and you can carry this over to GPS, mapping, surveying, and all forms of navigation, as they are all based on geodetic references, Mean Sea Level is now based on a fixed reference that does not move, One Tidal Bench Mark, Father’s Point/Rimouski, Quebec, Canada. All Leveling is based from there. But that was just leveling the Topographical heights of North America and is not the whole story. At any given point today, a frame of reference as taken by latitude and longitude will be necessary to calculate the GPS height for that location, as either above or below Mean Sea Level. GPS elevation is a component of several equations compared to the actual ground level (read Real leveled Topo, and referred to as the Orthometric surface) which was exhaustively leveled in the 1980's, the Ellipsoid Height, the Geoid Height, and a least squares adjustment taken to remove errors from the measurements. Mean Sea level is used to reference the elevation but it is not used as a part of the equation. Remember the earth's surface is the topographically leveled (meaning elevation determined though the method called differential leveling) earth we stand on, used as a frame of reference. It is the empirically leveled, monumented Bench Mark Elevation, and if not recently leveled it can be Adjusted. It is also simultaneously, the Orthometric Reference. The Geoid is that lumpy orb I referred to in an earlier post, which is a sort of ellipsoid that approximates the size of the earth, which isn't really a truly ellipsoidal shape because it is deformed by the forces of gravity. The ellipsoid is based from a smooth surface meant to be a model of the approximate overall size and shape of the earth as if the earth had neither gravity nor topographical features when compared to the actual Topographical surface. Geoid Height is a comparison of the geoid with the ellipsoid. Ellipsoid height is a comparison of the Ellipsoid with the topographical surface of the earth, or Orthometric surface. The Orthometric Height is a comparison of the Geoid to the actual Topo. Leveling is the most accurate way of determining elevation and was the basis for determining NAVD 88. It is not performed as a usual method of finding an elevation very often any more. The GPS uses the ellipsoidal reference, along with Latitude and Longitude. The GPS Satellite Constellation basically triangulates the GPS to a place and a height above or below the ellipsoid. This ellipsoidal height is not comparable to Orthometric Height, which is the actual height of the ground. This height has to be compared to a high resolution model of the Geoid, the gravitational model, which has a variable conversion factor based on any given latitude and longitude to convert an ellipsoidal height to an orthometric height. We have the capability to do this to a degree of accuracy that approaches that of leveling. Then we can do a leveling loop much like we can do multiple triangulation's and perform a least squares adjustment on the loop to enhance the accuracy of all our observations. Why do we do it this way? To correct the errors we see between the way we see the earth when we perform differential leveling on the actual surface (Orthometric surface), how a GPS actually sees the earth as based on radio telemetry (Ellipsoidal surface), and how gravimeters see the earth as based on measurements taken that base what we think form the shape of the geoid (Geoid surface). They all three differ a bit, but bringing the ellipsoid and the geoid together with the right models and formulas bring us to a single elevation. Again, for the sake of a uniform mathematical reference. Obviously what we believed back in the day and what we believe now are 2 different things. Geo, I hope the old model of NGVD Sea Level reference helps answer you. Your instance is really pre NGVD 29. I imagine they used a reference benchmark, which was of known height as compared to what was considered reference for that time. In 1899 the world was a smaller place and I imagine, even pre NGVD 29 and NAD 27 that the Tidal levels of the Gulf may have been a local frame of reference for the area at the time, again I imagine it was based on an averaged sea level of more than one place. This was probably averaged beyond the Gulf as well. The difficult thing about your instance is that here is a chiseled elevation that really has no Datum to reference itself against. It is not correct now, and was only correct for the duration the reference it was based on was considered correct. This is why a bench mark is generally not ascribed an elevation in person, at least not any more. We have learned we can improve upon all this, and as we do the number will change. A chiseled or stamped number becomes eternally incorrect with the first update. In closing, trying to explain all this is not really cake, and I may have made errors. I have proofed it but I may have overlooked something. If anyone has anything to add or feels that I may have been in error, please feel free to weigh in! Rob