Z15

I wish I had some of those olds disks to photograph and show here. But I retired and all that stuff is in the possesion of my former employer (State DOT). From looking at the RM photo, that disk looks very familar to many of the later disks set in the 1960 and 1970, the last with the USC & GS legend. Of those that I have found, there is a small flat stem about 1/2 inch in size and 3 inch long brazed to the cap and that is set into the concrete post without any other metal. It is very hard to determine scale from the close of photo and it would be a good idea to lay a 1 ft ruler etc next to the item being photographed for clarity. I would not report that mark unless I was 100% positive I was correct in my assumption. I have seen way too many people mistakenly assume the mark is destroyed, only to go out and find the mark within matter of minutes. I can remember one in particular. Our crew spent a couple of hours trying to find this Bench Mark. It was a mark we desperatly wanted to find because if it was not there, we would have to run levels (elevations) for about 5 miles farther (costly in manhours). The only reference that was left was the rr tracks that showed recent rehab. The other 2 witness's were a Mile Marker (that was gone) and a telegraph pole (that was gone). So one day after work the boss comes to my motel room and asks if I want to go take a walk with him to see if we prove the mark is gone. So we hiked about 1/2 mile down the tracks to the approx. location and proceeded to search for the pole and the Mile maker. I was walking along the woods line looking for the mile maker and found the oil sign, we measured ahead from there and found remnents of the old pole which was almost impossible to see in the brush. We then started digging in a location from these witnesses and found the bench mark almost 2 ft below the surface. The other guys never went into search detail that we did and thats why they erronously assumed the mark to be destroyed.

Something does not appear right to me. That looks like a pipe, in a round concrete monument? Am I correct that the object is hollow in the center like a pipe? These disk are either brass or bronze, not steel. Is that brass? The shank of the particular type of disk is only about 1/2 inch in diameter. Are you sure you have the correct position. Do not assume that the coords you have are correct unless you find the mark. It could be a coincidence that what you found is near the location. Did you try measuring from the RM's and see if the distance checks out? It is 46.808 meters (153.57 Ft) to RM 5 It is 83.247 meters (273.12 Ft) to RM 3 I think more research is needed before assuming the mark is destroyed. As to why the datesheet does not reflect any current changes, no one must have been to it in years or else they could not find it.

I have dug the underground up a few times. Here's is a station one of our party's found. Read the 1995 recovery. quote: The NGS Data SheetSee file dsdata.txt for more information about the datasheet.DATABASE = Sybase ,PROGRAM = datasheet, VERSION = 6.71 1 National Geodetic Survey, Retrieval Date = FEBRUARY 3, 2003 RL1102 *********************************************************************** RL1102 DESIGNATION - PAULDING RL1102 PID - RL1102 RL1102 STATE/COUNTY- MI/ONTONAGON RL1102 USGS QUAD - RL1102 RL1102 *CURRENT SURVEY CONTROL RL1102 ___________________________________________________________________ RL1102* NAD 83(1994)- 46 24 01.48403(N) 089 13 06.32336(W) ADJUSTED RL1102* NAVD 88 - 490.370 (meters) 1608.82 (feet) ADJUSTED RL1102 ___________________________________________________________________ RL1102 LAPLACE CORR- -3.66 (seconds) DEFLEC99 RL1102 GEOID HEIGHT- -31.54 (meters) GEOID99 RL1102 DYNAMIC HT - 490.381 (meters) 1608.86 (feet) COMP RL1102 MODELED GRAV- 980,620.5 (mgal) NAVD 88 RL1102 RL1102 HORZ ORDER - FIRST RL1102 VERT ORDER - SECOND CLASS 0 RL1102 RL1102.The horizontal coordinates were established by classical geodetic methods RL1102.and adjusted by the National Geodetic Survey in February 1997. RL1102 RL1102.The orthometric height was determined by differential leveling RL1102.and adjusted by the National Geodetic Survey in June 1991. RL1102 RL1102.The Laplace correction was computed from DEFLEC99 derived deflections. RL1102 RL1102.The geoid height was determined by GEOID99. RL1102 RL1102.The dynamic height is computed by dividing the NAVD 88 RL1102.geopotential number by the normal gravity value computed on the RL1102.Geodetic Reference System of 1980 (GRS 80) ellipsoid at 45 RL1102.degrees latitude (g = 980.6199 gals.). RL1102 RL1102.The modeled gravity was interpolated from observed gravity values. RL1102 RL1102; North East Units Scale Converg. RL1102;SPC MI N - 182,115.848 7,829,435.929 MT 0.99990485 -1 36 12.4 RL1102;UTM 16 - 5,140,928.987 329,467.697 MT 0.99995748 -1 36 24.9 RL1102 RL1102: Primary Azimuth Mark Grid Az RL1102:SPC MI N - PAULDING AZ MK 072 53 23.8 RL1102:UTM 16 - PAULDING AZ MK 072 53 36.3 RL1102 RL1102|---------------------------------------------------------------------| RL1102| PID Reference Object Distance Geod. Az | RL1102| dddmmss.s | RL1102| CJ3451 PAULDING AZ MK 0711711.4 | RL1102| RL1582 TROUT CREEK LOOKOUT TOWER USGS APPROX.18.0 KM 0755006.5 | RL1102| RL1104 PAULDING RM 2 30.078 METERS 25505 | RL1102| RL1604 TT 36 TX 11.945 METERS 27802 | RL1102| RL1103 PAULDING RM 1 25.636 METERS 34028 | RL1102|---------------------------------------------------------------------| RL1102 RL1102 SUPERSEDED SURVEY CONTROL RL1102 RL1102 NAD 83(1994)- 46 24 01.48164(N) 089 13 06.31877(W) AD( ) 1 RL1102 NAD 83(1986)- 46 24 01.48088(N) 089 13 06.31792(W) AD( ) 1 RL1102 NAD 27 - 46 24 01.67700(N) 089 13 05.80600(W) AD( ) 1 RL1102 NGVD 29 - 490.390 (m) 1608.89 (f) ADJ UNCH 2 0 RL1102 RL1102.Superseded values are not recommended for survey control. RL1102.NGS no longer adjusts projects to the NAD 27 or NGVD 29 datums. RL1102.See file dsdata.txt to determine how the superseded data were derived. RL1102 RL1102_U.S. NATIONAL GRID SPATIAL ADDRESS: 16TCS2946840929(NAD 83) RL1102_MARKER: DS = TRIANGULATION STATION DISK RL1102_SETTING: 7 = SET IN TOP OF CONCRETE MONUMENT RL1102_STAMPING: PAULDING 1939 RL1102_STABILITY: C = MAY HOLD, BUT OF TYPE COMMONLY SUBJECT TO RL1102+STABILITY: SURFACE MOTION RL1102 RL1102 HISTORY - Date Condition Report By RL1102 HISTORY - 1939 MONUMENTED CGS RL1102 HISTORY - 1940 GOOD CGS RL1102 HISTORY - 1948 GOOD NGS RL1102 HISTORY - 1952 GOOD CGS RL1102 HISTORY - 1975 GOOD NGS RL1102 HISTORY - 1975 GOOD NGS RL1102 HISTORY - 19951011 MARK NOT FOUND MIDT RL1102 HISTORY - 20010617 GOOD USPSQD RL1102 RL1102 STATION DESCRIPTION RL1102 RL1102'DESCRIBED BY COAST AND GEODETIC SURVEY 1939 (FBQ) RL1102'STATION IS ABOUT 2 MILES WEST OF THE TOWN OF PAULDING AND ON RL1102'LAND OWNED BY THE MICHIGAN CONSERVATION DEPARTMENT. IT IS IN THE RL1102'NORTHWEST QUARTER OF SECTION 8, T. 46 N., R. 39 W., 39.19 RL1102'FEET EAST OF THE PAULDING LOOKOUT TOWER WHICH IS ON THE RL1102'HIGHEST PART OF THE HILL. IT IS 92 FEET SOUTHEAST OF A WELL RL1102'PUMP AND ABOUT 27 YARDS EAST-SOUTHEAST OF THE SOUTHEAST CORNER RL1102'OF THE RANGERS HOUSE. THE MARK PROJECTS RL1102'ABOUT 8 INCHES ABOVE THE GROUND AND IS STAMPED PAULDING 1939. RL1102' RL1102'TO REACH THE STATION FROM THE TOWN OF PAULDING, AT THE RAILROAD RL1102'CROSSING DRIVE NORTH ON U.S. HIGHWAY 45 FOR 0.1 MILE TO A RL1102'T-ROAD WEST, TURN LEFT, AND DRIVE WEST ON THE MAIN GRAVEL ROAD RL1102'FOR 2.1 MILES TO A SIGN STATE FIRE TOWER 1/8 MILE. TURN RL1102'LEFT AND DRIVE UPHILL 0.2 MILE TO THE LOOKOUT TOWER AND THE RL1102'STATION. RL1102' RL1102'REFERENCE MARK NO. 1 IS 84.01 FEET, HORIZONTAL DISTANCE, RL1102'NORTH-NORTHWEST OF THE STATION AND 57 FEET NORTHEAST OF THE RL1102'WELL PUMP. IT IS ABOUT 5 FEET LOWER THAN THE STATION. THE RL1102'MARK PROJECTS 8 INCHES ABOVE GROUND AND IS STAMPED RL1102'PAULDING NO 1 1939. RL1102' RL1102'REFERENCE MARK NO. 2 IS 98.70 FEET, HORIZONTAL DISTANCE, RL1102'WEST-SOUTHWEST OF THE STATION AND 33 FEET SOUTH OF THE SOUTHEAST RL1102'CORNER OF THE RANGERS HOUSE. IT IS ABOUT 5 FEET LOWER THAN RL1102'THE STATION. THE MARK PROJECTS 8 INCHES ABOVE RL1102'GROUND AND IS STAMPED PAULDING NO 2 1939. RL1102' RL1102'THE AZIMUTH MARK IS ABOUT 1.2 MILES EAST-NORTHEAST OF THE RL1102'STATION. IT IS 28 FEET SOUTHWEST OF THE CENTER OF THE RAILROAD RL1102'TRACKS, 21 FEET WEST OF A TELEPHONE POLE, 22 FEET NORTH OF RL1102'THE CENTER OF THE GRAVEL ROAD, AND 109 FEET WEST-NORTHWEST RL1102'OF THE CENTER OF THE RAILROAD AND GRAVEL ROAD CROSSING. THE RL1102'MARK PROJECTS 8 INCHES ABOVE THE GROUND AND IS RL1102'STAMPED PAULDING 1939. RL1102' RL1102'TO REACH THE AZIMUTH MARK FROM THE RAILROAD CROSSING IN RL1102'PAULDING, DRIVE NORTH ON U.S. HIGHWAY 45 FOR 0.1 MILE THEN RL1102'TURN LEFT AND DRIVE WEST ON A GRAVEL ROAD FOR 0.9 MILE TO RL1102'A RAILROAD CROSSING AND THE MARK. RL1102' RL1102'ALL MARKS ARE WITNESSES WITH 4-INCH SQUARE WHITE WOODEN RL1102'POSTS WHICH PROJECT ABOUT 2-1/2 FEET ABOVE THE GROUND. RL1102' RL1102'TT 36 TX 1938 (U.S.G.S.) IS 39.19 FEET WEST OF THE STATION RL1102'AND ON THE HIGHEST PART OF THE HILL. IT IS A STANDARD U.S. RL1102'GEOLOGICAL SURVEY BENCH MARK DISK SET FLUSH WITH THE SURFACE RL1102'OF THE GROUND AND IN THE CENTER OF AN 8- BY 9-INCH CONCRETE RL1102'POST. IT IS STAMPED TT 36 TX 1938. THE DISK IS UNDER THE RL1102'APPROXIMATE CENTER OF THE PAULDING LOOKOUT TOWER, WHICH RL1102'IS A STEEL STRUCTURE AND 90 FEET HIGH AND HAS A GLASS ENCLOSED RL1102'LOOKOUT ROOM ON THE TOP. THE TOWER BELONGS TO THE MICHIGAN RL1102'CONSERVATION DEPARTMENT. RL1102' RL1102'A 37-FOOT TOWER IS NEEDED TO SEE A 123-FOOT TOWER AT COPPS. RL1102' RL1102'A 37-FOOT TOWER IS NEEDED TO SEE A 77-FOOT TOWER AT BASS. RL1102' RL1102'A 37-FOOT TOWER IS NEEDED TO SEE A 103-FOOT TOWER AT BERGLAND. RL1102' RL1102'A 37-FOOT TOWER IS NEEDED TO SEE A 77-FOOT TOWER AT NORWICH. RL1102' RL1102'HEIGHT OF LIGHT ABOVE STATION MARK - 34 METERS. RL1102 RL1102 STATION RECOVERY (1940) RL1102 RL1102'RECOVERY NOTE BY COAST AND GEODETIC SURVEY 1940 (KBJ) RL1102'STATION RECOVERED AS DESCRIBED BY F.B. QUINN IN 1939. ALL RL1102'MARKS WERE FOUND TO BE IN GOOD CONDITION. DISTANCES CHECK RL1102'AS DESCRIBED. THE 1939 DIRECTIONS DO NOT AGREE WITH THOSE RL1102'OF 1940. RL1102 RL1102 STATION RECOVERY (1948) RL1102 RL1102'RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1948 RL1102'2.6 MI W FROM PAULDING. RL1102'ABOUT 0.25 MILE NORTH ALONG U.S. HIGHWAY 45 FROM THE POST RL1102'OFFICE AT PAULDING, THENCE ABOUT 2.15 MILES SOUTHWEST ALONG A RL1102'GRAVEL ROAD, THENCE ABOUT 0.25 MILE SOUTH ALONG A ROAD, AT THE RL1102'PAULDING FIRE LOOKOUT TOWER, 26 FEET EAST OF THE SOUTHEAST RL1102'LEG OF THE TOWER, 95 FEET EAST OF THE SOUTHEAST CORNER OF A LOG RL1102'BUILDING, 85 FEET SOUTH-SOUTHEAST OF R.M. NO. 1, 5 FEET SOUTHEAST RL1102'OF A 3 1/2 INCH PINE TREE, AND SET IN THE TOP OF A CONCRETE RL1102'POST PROJECTING 8 INCHES. RL1102 RL1102 STATION RECOVERY (1952) RL1102 RL1102'RECOVERY NOTE BY COAST AND GEODETIC SURVEY 1952 (LFW) RL1102'THE STATION WAS RECOVERED AND ALL MARKS WERE FOUND IN GOOD RL1102'CONDITION. AS SEVERAL DISCREPANCIES WERE FOUND IN THE ORIGINAL RL1102'DESCRIPTION A COMPLETE NEW DESCRIPTION FOLLOWS. RL1102' RL1102'THE STATION IS LOCATED ABOUT 2.0 MILES WEST OF PAULDING RL1102'ON A WOODED HILL NEAR THE PAULDING LOOKOUT TOWER. RL1102' RL1102'TO REACH THE STATION FROM THE GENERAL STORE IN PAULDING, RL1102'GO NORTH ON U.S. HIGHWAY 45 FOR 0.2 MILE TO A BRIDGE. CROSS RL1102'BRIDGE AND CONTINUE NORTH ON HIGHWAY 0.1 MILE TO A GRAVEL RL1102'ROAD TO THE LEFT. TURN LEFT, GO WEST 0.9 MILE TO THE AZIMUTH RL1102'MARK ON THE RIGHT AS DESCRIBED BELOW. CONTINUE WESTERLY RL1102'1.2 MILES TO A ROAD LEFT. TURN LEFT, GO SOUTHERLY 0.2 MILE RL1102'TO THE TOP OF THE HILL AT THE SITE OF THE LOOKOUT TOWER RL1102'AND STATION. RL1102' RL1102'THE STATION MARK IS STAMPED PAULDING 1939. IT IS A STANDARD RL1102'DISK SET IN A CONCRETE MONUMENT. RL1102'THE MARK PROJECTS 7 INCHES AND IS LOCATED 39 FEET EAST OF RL1102'THE CENTER OF THE LOOKOUT TOWER AND 3 FEET NORTH OF A WHITE RL1102'WITNESS POST. RL1102' RL1102'REFERENCE MARK 1 IS STAMPED PAULDING NO 1 1939. IT IS A RL1102'STANDARD DISK SET IN A CONCRETE. RL1102'THE MARK PROJECTS 3 INCHES AND IS LOCATED 2.5 RL1102'FEET SOUTH OF A WHITE WITNESS POST. RL1102' RL1102'REFERENCE MARK 2 IS STAMPED PAULDING NO 2 1939. IT IS A RL1102'STANDARD DISK SET IN A CONCRETE. RL1102'THE MARK PROJECTS 6 INCHES AND IS LOCATED 2.5 RL1102'FEET EAST OF A WHITE WITNESS POST. RL1102' RL1102'THE AZIMUTH MARK IS STAMPED PAULDING 1939. IT IS A STANDARD RL1102'DISK SET IN A CONCRETE MONUMENT. RL1102'IT PROJECTS 4 INCHES AND IS LOCATED 21 FEET NORTH OF THE RL1102'CENTERLINE OF A GRAVEL ROAD, 21 FEET WEST OF TELEPHONE POLE RL1102'NO. 476 AND 3 FEET WEST OF A WHITE WITNESS POST. RL1102' RL1102'A U.S. GEOLOGICAL SURVEY BENCH MARK, STAMPED TT 36 TX 1938, RL1102'IS SET IN A CONCRETE MONUMENT, FLUSH WITH THE GROUND AND RL1102'LOCATED IN THE CENTER OF THE BASE OF THE LOOKOUT TOWER. RL1102 RL1102 STATION RECOVERY (1975) RL1102 RL1102'RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1975 (JLC) RL1102'NO MEASUREMENT BETWEEN THE RMS DUE TO TREES ON LINE. RL1102' RL1102'THE STATION MARK, REFERENCE MARKS 1 AND 2, THE AZIMUTH MARK AND THE RL1102'USGS MARK WERE RECOVERED AND FOUND IN GOOD CONDITION. THE RL1102'HORIZONTAL DIRECTIONS AND THE DISTANCE TO THE REFERENCE MARKS RL1102'CHECKED THE 1939 OBSERVATIONS ADEQUATELY, HOWEVER, HORIZONTAL RL1102'DIRECTIONS TO THE USGS MARK WAS IN DIFFERENCE OF 4 MINUTES AND 34 RL1102'SECONDS SMALLER, THE DISTANCE CHECKED ADEQUATELY. A COMPLETE RL1102'NEW DESCRIPTION FOLLOWS. RL1102' RL1102'THE STATION IS LOCATED ABOUT 10 MILES NORTH-NORTHWEST OF WATERSMEET, RL1102'10 MILES SOUTH-SOUTHWEST OF BRUCE CROSSING, 1-1/2 MILES WEST OF RL1102'PAULDING AND ON LAND OF THE US FOREST SERVICE, MR. JAMES A. CARON, RL1102'DISTRICT RANGER, WATERSMEET RANGER STATION, WATERSMEET, MICHIGAN. RL1102' RL1102'TO REACH THE STATION FROM PAULDING, GO NORTH ON U.S. HIGHWAY 45 FOR RL1102'0.2 MILE TO A BRIDGE, CONTINUE NORTH FOR 0.1 MILE TO A GRAVELED SIDE RL1102'ROAD LEFT. TURN LEFT AND GO WEST ON THE GRAVELED ROAD FOR 0.95 RL1102'MILE TO THE AZIMUTH MARK ON THE RIGHT, CONTINUE WEST ON THE RL1102'GRAVELED ROAD FOR 1.2 MILES TO A SIDE ROAD LEFT. TURN LEFT AND GO RL1102'SOUTHERLY, UPHILL, FOR 0.2 MILE TO THE TOP OF HILL AND RL1102'STATION. RL1102' RL1102'STATION MARKS ARE STANDARD DISKS STAMPED PAULDING 1939. THE SURFACE RL1102'DISK IS SET IN THE TOP OF A 12-INCH SQUARE CONCRETE MONUMENT THAT RL1102'PROJECTS 12 INCHES ABOVE THE GROUND SURFACE. IT IS 39 FEET EAST OF RL1102'A METAL WITNESS POST, 14 FEET SOUTH OF AN 18-INCH PINE TREE AND 4 RL1102'FEET NORTH OF A METAL WITNESS POST. THE UNDERGROUND DISK IS SET IN RL1102'THE TOP OF AN IRREGULAR MASS OF CONCRETE 40 INCHES BELOW THE RL1102'GROUND SURFACE. RL1102' RL1102'REFERENCE MARK 1, A STANDARD DISK STAMPED PAULDING NO 1 1939, IS SET RL1102'IN THE TOP OF A 12-INCH SQUARE CONCRETE MONUMENT THAT PROJECTS 4 RL1102'INCHES ABOVE THE GROUND SURFACE. IT IS 12 FEET SOUTH OF THE CENTER RL1102'OF TRACK ROAD AND 2 FEET EAST OF A METAL WITNESS POST. RL1102' RL1102'REFERENCE MARK 2, A STANDARD DISK STAMPED PAULDING NO 2 1939, IS SET RL1102'IN THE TOP OF A 12-INCH SQUARE CONCRETE MONUMENT THAT PROJECTS 4 RL1102'INCHES ABOVE THE GROUND SURFACE. IT IS 22 FEET SOUTH-SOUTHEAST OF RL1102'A 14-INCH SPRUCE TREE AND 2 FEET SOUTH OF A METAL WITNESS POST. RL1102' RL1102'AZIMUTH MARK, A STANDARD DISK STAMPED PAULDING 1939, IS SET IN THE RL1102'TOP OF A 12-INCH SQUARE CONCRETE MONUMENT THAT PROJECTS 4 INCHES RL1102'ABOVE THE GROUND SURFACE. IT IS 21 FEET NORTH OF THE CENTER OF THE RL1102'GRAVELED ROAD AND 2 FEET EAST OF A METAL WITNESS POST. RL1102' RL1102'USGS MARK, A STANDARD U.S. GEOLOGICAL SURVEY BENCH MARK DISK STAMPED RL1102'TT 36 TX 1938, IS SET IN THE TOP OF A 6-INCH SQUARE CONCRETE RL1102'MONUMENT THAT IS FLUSH WITH THE GROUND SURFACE. IT IS 1 FOOT SOUTH RL1102'OF A METAL WITNESS POST AND IN THE CENTER OF 4 CONCRETE RL1102'FOOTINGS FOR THE OLD LOOKOUT TOWER. RL1102' RL1102'AIRLINE DISTANCE AND DIRECTION FROM NEAREST TOWN--1-1/2 MILES WEST RL1102'OF PAULDING. RL1102' RL1102'HEIGHT OF LIGHT ABOVE STATION MARK 85.3 FEET. RL1102 RL1102 STATION RECOVERY (1975) RL1102 RL1102'RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1975 RL1102'0.3 MILE NORTH ALONG U.S. HIGHWAY 45 FROM THE NORTH EDGE OF PAULDING, RL1102'THENCE 2.15 MILES WEST ALONG A GRAVELED ROAD, THENCE 0.2 MILE RL1102'SOUTHERLY, UPHILL, ALONG A TRACK ROAD, 39 FEET EAST OF A METAL RL1102'WITNESS POST, 14 FEET SOUTH OF AN 18-INCH PINE TREE AND 4.0 FEET WEST RL1102'OF A METAL WITNESS POST, AND SET IN THE TOP OF A 12-INCH SQUARE RL1102'CONCRETE MONUMENT THAT PROJECTS 12 INCHES ABOVE THE SURFACE OF THE RL1102'GROUND. NOTE-- THE LOOKOUT TOWER THAT WAS PREVIOUSLY MENTIONED HAS RL1102'BEEN TORN DOWN. RL1102 RL1102 STATION RECOVERY (1995) RL1102 RL1102'RECOVERY NOTE BY MICHIGAN DEPARTMENT OF TRANSPORTATION 1995 (BRT) RL1102'MARK WAS FOUND REPLACED WITH AN IRON PIPE FROM REFERENCE MONUMENTS BY RL1102'RICHARD L. DRAHN, US FOREST SERVICE, UNDERGROUND MARK WAS FOUND PILED RL1102'IN STONES SURROUNDING FOREST SERVICE PIPE. PER INSTRUCTIONS FROM NGS RL1102'STATE GEODETIC ADVISOR THE USFS MARK WAS REMOVED AND A NEW STATION WAS RL1102'ESTABLISHED. FOR FURTHER INFORMATION CONTACT STATE GEODETIC ADVISOR. RL1102 RL1102 STATION RECOVERY (2001) RL1102 RL1102'RECOVERY NOTE BY US POWER SQUADRON 2001 (GG) RL1102'RECOVERED IN GOOD CONDITION. *** retrieval complete. Elapsed Time = 00:00:05

Nothing, they would not use them at all. They will only allow these updates by their own field crews who have the software to make the updates. All you can do it add text. I would recommed you not add your GPS coordinates to any reports to NGS. On this site it OK.

Here's an example of a simple updated decription of one I recovered a few years back. quote: The NGS Data SheetSee file dsdata.txt for more information about the datasheet.DATABASE = Sybase ,PROGRAM = datasheet, VERSION = 6.71 1 National Geodetic Survey, Retrieval Date = JANUARY 31, 2003 RL0117 *********************************************************************** RL0117 DESIGNATION - F 160 RL0117 PID - RL0117 RL0117 STATE/COUNTY- MI/BARAGA RL0117 USGS QUAD - ALBERTA (1985) RL0117 RL0117 *CURRENT SURVEY CONTROL RL0117 ___________________________________________________________________ RL0117* NAD 83(1986)- 46 44 46. (N) 088 25 54. (W) SCALED RL0117* NAVD 88 - 259.951 (meters) 852.86 (feet) ADJUSTED RL0117 ___________________________________________________________________ RL0117 GEOID HEIGHT- -34.03 (meters) GEOID99 RL0117 DYNAMIC HT - 259.966 (meters) 852.91 (feet) COMP RL0117 MODELED GRAV- 980,663.0 (mgal) NAVD 88 RL0117 RL0117 VERT ORDER - SECOND CLASS 0 RL0117 RL0117.The horizontal coordinates were scaled from a topographic map and have RL0117.an estimated accuracy of +/- 6 seconds. RL0117 RL0117.The orthometric height was determined by differential leveling RL0117.and adjusted by the National Geodetic Survey in June 1991. RL0117 RL0117.The geoid height was determined by GEOID99. RL0117 RL0117.The dynamic height is computed by dividing the NAVD 88 RL0117.geopotential number by the normal gravity value computed on the RL0117.Geodetic Reference System of 1980 (GRS 80) ellipsoid at 45 RL0117.degrees latitude (g = 980.6199 gals.). RL0117 RL0117.The modeled gravity was interpolated from observed gravity values. RL0117 RL0117; North East Units Estimated Accuracy RL0117;SPC MI N - 219,140. 7,890,610. MT (+/- 180 meters Scaled) RL0117 RL0117 SUPERSEDED SURVEY CONTROL RL0117 RL0117 NGVD 29 - 259.924 (m) 852.77 (f) ADJ UNCH 2 0 RL0117 RL0117.Superseded values are not recommended for survey control. RL0117.NGS no longer adjusts projects to the NAD 27 or NGVD 29 datums. RL0117.See file dsdata.txt to determine how the superseded data were derived. RL0117 RL0117_U.S. NATIONAL GRID SPATIAL ADDRESS: 16TCS906779(NAD 83) RL0117_MARKER: DB = BENCH MARK DISK RL0117_SETTING: 7 = SET IN TOP OF CONCRETE MONUMENT RL0117_STAMPING: F 160 1948 RL0117_STABILITY: C = MAY HOLD, BUT OF TYPE COMMONLY SUBJECT TO RL0117+STABILITY: SURFACE MOTION RL0117_SATELLITE: THE SITE LOCATION WAS REPORTED AS SUITABLE FOR RL0117+SATELLITE: SATELLITE OBSERVATIONS - November 06, 2000 RL0117 RL0117 HISTORY - Date Condition Report By RL0117 HISTORY - 1948 MONUMENTED CGS RL0117 HISTORY - 1982 MARK NOT FOUND USGS RL0117 HISTORY - 19920820 MARK NOT FOUND USPSQD RL0117 HISTORY - 20001106 GOOD MIDT RL0117 RL0117 STATION DESCRIPTION RL0117 RL0117'DESCRIBED BY COAST AND GEODETIC SURVEY 1948 RL0117'1.2 MI E FROM L ANSE. RL0117'ABOUT 1.25 MILES EAST ALONG U.S. HIGHWAY 41 FROM THE DULUTH, RL0117'SOUTH SHORE AND ATLANTIC RAILWAY STATION AT L ANSE, AT A CURVE RL0117'IN THE HIGHWAY WITH TANGENTS WEST AND SOUTHEAST AND THE JUNCTION RL0117'OF A GRAVEL ROAD EAST, 285 FEET EAST-NORTHEAST OF THE CENTER RL0117'OF THE JUNCTION, 34 FEET NORTH OF THE CENTER LINE OF THE GRAVEL RL0117'ROAD EAST, 92 FEET NORTH-NORTHEAST AND ACROSS THE GRAVEL ROAD RL0117'FROM THE CENTER LINE OF THE HIGHWAY, 63 FEET NORTH AND ACROSS RL0117'THE GRAVEL ROAD FROM A POWER POLE BETWEEN HIGHWAY AND GRAVEL RL0117'ROAD, 24 FEET WEST-NORTHWEST OF A TELEPHONE POLE, 2 FEET RL0117'NORTHEAST OF A WHITE WOODEN WITNESS POST, 2 1/2 FEET ABOVE THE RL0117'GRAVEL ROAD AND SET IN THE TOP OF A CONCRETE POST PROJECTING RL0117'4 INCHES. RL0117 RL0117 STATION RECOVERY (1982) RL0117 RL0117'RECOVERY NOTE BY US GEOLOGICAL SURVEY 1982 RL0117'MARK NOT FOUND. RL0117 RL0117 STATION RECOVERY (1992) RL0117 RL0117'RECOVERY NOTE BY US POWER SQUADRON 1992 (GG) RL0117'MARK NOT FOUND. RL0117 RL0117 STATION RECOVERY (2000) RL0117 RL0117'RECOVERY NOTE BY MICHIGAN DEPARTMENT OF TRANSPORTATION 2000 (MPR) RL0117'L'ANSE, 0.45 MI EAST ALONG US-41 FROM THE M.D.O.T. SERVICE FACILITY, RL0117'THENCE 0.175 MI N ALONG DYNAMITE HILL RD, 94 FT S80E OF A CHAIN LINK RL0117'FENCE CORNER, 92 FT N OF ROAD C/L, 23 FT N60W OF TELEPHONE POLE 50414, RL0117'IN LINE WITH 4 WOOD POSTS, 1 FT ABOVE GROUND AND 2.5 FT ABOVE THE RL0117'ROAD, 1 FT N OF A WITNESS POST. PROPERTY OWNER = L'ANSE MANF. CO. *** retrieval complete. Elapsed Time = 00:00:00

When it goes online it will show up on you sky plot. Some that have been launched in the past had technical difficulties and neve went healthy or died an early death.

One of the reasons for having the scaled Lats and Lon is to make it easy to search the database by position. Without these, you could not search by area other than a state or county. NGS MAP WEB SITE FOR LOCATING CONTROL You need a fast connection to make good use of this site. It loads in a few seconds on my cable modem but could take much longer on dialups?

It explains what to do on this site

I don't have a photo of them that I can fin. They started using them in the late 40's. I have found a number of the posta over the years that were placed in 1948. The are 4" Sq about 2 ft high set in concrete. The are painted white with the letters U S B M stenciled on one side from top to bottom. Most of them though have rotted away with time, the one in found were all under heavy tree cover. I found a mint looking one and I gave it to a fellow surveyor for his private museum collection of survey marks.

A standard survey disk like the rest. Its just an old terminology.

People have the wrong impression of a lot of this local control. While it may be considered public domain, a lot of it is not maintained in a way the public would be able to find. Most of our control was only documented on construction plans and in Survey field notes, their is no description like the NGS datasheet so to be able to find it by a novice would be next to impossible. We did not have the manpower nor the management inclinations to maintain a database of control. Yes, some of the control is in the NGS database but those were specific projects funded with federal money and done to NGS spec's. Our programs were to build highways and transportation projects, not maintain a Survey data base. There was not organized plan to make this data accurate across the state or provide a service to the public. Our organization was controlled by engineers for engineers, surveyors were only 1/100 of the work force, maintaining a network of survey control was not on thier list of important things. Another thing is that with our org. we had construction techs using GPS to set control for projects, often this control was not that accurate to NGS spec's or only project specific such as on a old plan corrodinate systems or elevations not compatiable with current published NGS data. They often used what is called "Single Point Position" or a "3D Transformation" and only usefull to the design engineer. If you wanted to find the info you may have to file a freedom of information request and do all the research yourself. Our only obligation was to tell you were you might find the information and to let you see it. [This message was edited by elcamino on January 24, 2003 at 07:47 AM.]

Many of the state marks are for their own use in highway planning/construction and many other purposes. When I was with the MDOT, we set many GPS and Bench Marks for our own use. They will not be published. They are many private companies setting GPS control points too. Its not intended for the public to use. So you may as well forget about these marks that are not shown here in the NGS database. You are just wasting your time with these. Look for the ones you info on.

FAA

What was the geometry of the SV's. If the GDOP was a high, that could account for the shift in position. If the birds are low in the sky or all bunched up in one spot, you can get a weak solution esp. with only 4-6 birds. In surveying we need at least 5 SV's to get a good position, 1 SV each for X,Y,Z,Time + 1 more for check = 5 SV's, if less than 5 we would not survey because of poor acc. Even with 5, the DOP of 5 or more usually meant a weak solultion. It all depends on you Latitude (not attitude). SV = Spave Vehicles GDOP = Geometric Dilution of Precision DOP - Dilution of Precision Signals bending as the travel thru the atmospehere's etc. Also, are there any radio towers close to the location? They can interfer with signals on some receivers.

For the most part, a surveyor would not want the flagging (tape as you call it) to degrade. Want it last to warn or alert everyone of the presence of a valuable survey marker or property line etc.

They are all for aerial photography. They ID the location of the survey mark on the photograph. They are at least 3 types that we used for highway planning etc. The 'X' , 'V' or a 'T' shapped. What was used was usually left up to the descrection of the survey crew. An 'X' was used when we could set it, the 'V' and 'T' were used when space was not available, like for instance painted them at the edge of the pavement so the survey crew did not have to be out in traffic. Often times we would just paint a straight line accross the centerline a specified distance apart down the road for scaling of the photographs for "photolog" plans where they used the photograph as the base plans. We also used white vinyl over black vinyl for targets out of hard surfaced areas, out in fields, in the woods etc. The larger the target the higher the filght.

Another thing NOS use's a different numbers scheme for thier marks. for instance the 0136 is probably part of longer number like 909 0136 Look closer at the disk and see if you might have missed some stamped numbers. Also they may be a conflict with the point ID and they changed it slighly in the DB so as not to be confused with another point. Exhample The NGS Data SheetSee file dsdata.txt for more information about the datasheet.DATABASE = Sybase ,PROGRAM = datasheet, VERSION = 6.70 1 National Geodetic Survey, Retrieval Date = JANUARY 21, 2003 RJ0272 *********************************************************************** RJ0272 TIDAL BM - This is a Tidal Bench Mark. RJ0272 DESIGNATION - 909 9004 IROQUOIS 1 RJ0272 PID - RJ0272 RJ0272 STATE/COUNTY- MI/CHIPPEWA RJ0272 USGS QUAD - DOLLAR SETTLEMENT (1976) RJ0272 RJ0272 *CURRENT SURVEY CONTROL RJ0272 ___________________________________________________________________ RJ0272* NAD 83(1986)- 46 29 02. (N) 084 37 55. (W) SCALED RJ0272* NAVD 88 - 187.314 (meters) 614.55 (feet) ADJUSTED RJ0272 ___________________________________________________________________ RJ0272 GEOID HEIGHT- -36.47 (meters) GEOID99 RJ0272 DYNAMIC HT - 187.323 (meters) 614.58 (feet) COMP RJ0272 MODELED GRAV- 980,661.2 (mgal) NAVD 88 RJ0272 RJ0272 VERT ORDER - FIRST CLASS 0 RJ0272 RJ0272.The horizontal coordinates were scaled from a topographic map and have RJ0272.an estimated accuracy of +/- 6 seconds. RJ0272 RJ0272.The orthometric height was determined by differential leveling RJ0272.and adjusted by the National Geodetic Survey in June 1991. RJ0272 RJ0272.This Tidal Bench Mark is designated as VM 13358 RJ0272.by the Center for Operational Oceanographic Products and Services. RJ0272 RJ0272.The geoid height was determined by GEOID99. RJ0272 RJ0272.The dynamic height is computed by dividing the NAVD 88 RJ0272.geopotential number by the normal gravity value computed on the RJ0272.Geodetic Reference System of 1980 (GRS 80) ellipsoid at 45 RJ0272.degrees latitude (g = 980.6199 gals.). RJ0272 RJ0272.The modeled gravity was interpolated from observed gravity values. RJ0272 RJ0272; North East Units Estimated Accuracy RJ0272;SPC MI N - 191,720. 8,181,790. MT (+/- 180 meters Scaled) RJ0272 RJ0272 SUPERSEDED SURVEY CONTROL RJ0272 RJ0272 NGVD 29 - 187.27 (m) 614.4 (f) COMPUTED 1 0 RJ0272 RJ0272.Superseded values are not recommended for survey control. RJ0272.NGS no longer adjusts projects to the NAD 27 or NGVD 29 datums. RJ0272.See file dsdata.txt to determine how the superseded data were derived. RJ0272 RJ0272_U.S. NATIONAL GRID SPATIAL ADDRESS: 16TFS817505(NAD 83) RJ0272_MARKER: Z = SEE DESCRIPTION RJ0272_SETTING: 7 = SET IN TOP OF CONCRETE MONUMENT RJ0272_MARK LOGO: NONE RJ0272_PROJECTION: FLUSH RJ0272_MAGNETIC: O = OTHER; SEE DESCRIPTION RJ0272_STABILITY: C = MAY HOLD, BUT OF TYPE COMMONLY SUBJECT TO RJ0272+STABILITY: SURFACE MOTION RJ0272 RJ0272 HISTORY - Date Condition Report By RJ0272 HISTORY - 1901 MONUMENTED USLS RJ0272 HISTORY - 1972 GOOD USLS RJ0272 HISTORY - 1983 MARK NOT FOUND NGS RJ0272 HISTORY - 19941003 GOOD NOS RJ0272 HISTORY - 19950907 GOOD NOS RJ0272 RJ0272 STATION DESCRIPTION RJ0272 RJ0272'DESCRIBED BY US LAKE SURVEY 1972 RJ0272'AT POINT IROQUOIS. RJ0272'IROQUOIS NO 1 IS AT POINT IROQUOIS, CHIPPEWA COUNTY, MICHIGAN, RJ0272'ON U.S. GOVERNMENT PROPERTY, NEAR EAST-WEST COBBESTONE WALL RJ0272'SOUTH OF OLD LIGHTHOUSE DWELLING MAINTANCED BY U.S. FOREST RJ0272'SERVICE AS A HISTORICAL SITE, 87.5 FEET SOUTHEAST OF SOUTHWEST RJ0272'CORNER AND 76.4 FEET SOUTH OF SOUTHEAST CORNER OF DWELLING, 55.0 RJ0272'FEET EAST OF THE FLAGPOLE, 8.0 FEET EAST OF EXTENDED LINE OF RJ0272'EAST FACE OF THE DWELLING, UNDER NORTHWEST CORNER OF SECOND RJ0272'COBBESTONE POST FROM SOUTHEAST CORNER OF WALL, 2-FEET BELOW RJ0272'THE GROUND SURFACE, BEING HIGHEST POINT ON TOP OF A BRASS PLUG RJ0272'SET INTO TOP OF A HORIZONTAL STONE POST. LOCATION IS MARKED BY RJ0272'A CAPPED 1-INCH DIAMETER IRON PIPE PROJECTING 1-FOOT ABOVE RJ0272'THE GROUND. RJ0272 RJ0272 STATION RECOVERY (1983) RJ0272 RJ0272'RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1983 RJ0272'NOT RECOVERED THIS SURVEY, INADEQUATE DESCRIPTION. RJ0272 RJ0272 STATION RECOVERY (1994) RJ0272 RJ0272'RECOVERY NOTE BY NATIONAL OCEAN SERVICE 1994 (MJB) RJ0272'IROQUOIS 1 IS AT POINT IROQUOIS, CHIPPEWA COUNTY, MICHIGAN, 0.5 MILE RJ0272'(0.8 KM) NORTH ALONG STATE ROUTE 221 FROM THE POST OFFICE IN BRIMLEY, RJ0272'THENCE 7.25 MILE (11.67 KM) NORTHWEST ALONG ROUTE 1 (ASPHALT ROAD) , RJ0272'AT HISTORIC LIGHTHOUSE SITE, SOUTH OF THE LIGHTHOUSE DWELLING UNDER RJ0272'THE NORTHWEST CORNER OF THE SECOND COBBLESTONE POST FROM THE EAST END RJ0272'OF THE EAST-WEST COBBESTONE WALL, 26.5 METERS (86.9 FT) SOUTHEAST OF RJ0272'SOUTHWEST CORNER OF THE DWELLING, 23.29 METERS (76.41 FT) SOUTH OF RJ0272'SOUTHEAST CORNER OF DWELLING, 16.76 METERS (54.99 FT) EAST OF THE RJ0272'FLAGPOLE, 0.67 METERS (2.20 FT) BELOW THE GROUND SURFACE, BEING RJ0272'HIGHEST POINT ON TOP OF A BRASS PLUG SET INTO TOP OF A HORIZONTAL RJ0272'STONE POST. BM IS MARKED BY A STANDARD WITNESS POST AND IS ACCESSIBLE RJ0272'BY A 5-INCH PVC PIPE. RJ0272 RJ0272 STATION RECOVERY (1995) RJ0272 RJ0272'RECOVERY NOTE BY NATIONAL OCEAN SERVICE 1995 (MJB) RJ0272'RECOVERED AS DESCRIBED. *** retrieval complete. Elapsed Time = 00:00:03

Its just a typo from what I surmise I have seen this many times where the post is said to be round and it actually square in the field and vice-versa. fyi When the combined all this data into a database, they had to type serveal 100,000 points into the system. They did not start the DB in the 1700's but comiled this info in the 80's and 90's into the DB there is today. All this data has to be hand keyed in and mistakes are common. So don't be alarmed if something is not exactly as described. They did a pretty good job considering all the information that is in the DB's.

Data Sheet by Control Point Name Data Sheet by Point Radius Data Sheet by PID

quote:JE1942''FOLLOWING IS A DESCRIPTION FOR THE STATION MARK.JE1942'' JE1942''STATION MARKS ARE STANDARD DISKS STAMPED HOLMES 1934 1968. THE JE1942''SURFACE DISK IS SET IN THE TOP OF A SQUARE CONCRETE POST WHICH IS JE1942''FLUSH WITH THE SURFACE OF THE GROUND. IT IS 45.5 FEET EAST OF THE JE1942''EAST EDGE OF A MANHOLE COVER, 34.5 FEET WEST-SOUTHWEST OF THE JE1942''NORTHWEST CORNER OF THE PUMPING STATION, 32.5 FEET SOUTHEAST OF JE1942''THE SOUTHEAST CORNER OF A CYCLONE FENCE AROUND VOLTAGE JE1942''TRANSFORMERS, 29.5 FEET WEST-NORTHWEST OF THE SOUTHWEST CORNER JE1942''OF THE PUMPING STATION, AND 15 FEET NORTHEAST OF A FENCE AROUND JE1942''THE PUMPING STATION. THE UNDERGROUND DISK IS SET IN AN JE1942''IRREGULAR MASS OF CONCRETE 36 INCHES BELOW THE SURFACE OF THE JE1942''GROUND. Use the newest description. It says its a concrete post flush with the ground surface. There underground mark is 3 feet deep.

I found it. quote: The NGS Data SheetSee file dsdata.txt for more information about the datasheet.DATABASE = Sybase ,PROGRAM = datasheet, VERSION = 6.70 1 National Geodetic Survey, Retrieval Date = JANUARY 20, 2003 GU2036 *********************************************************************** GU2036 DESIGNATION - M 1192 GU2036 PID - GU2036 GU2036 STATE/COUNTY- CA/MONTEREY GU2036 USGS QUAD - SAN JUAN BAUTISTA (1993) GU2036 GU2036 *CURRENT SURVEY CONTROL GU2036 ___________________________________________________________________ GU2036* NAD 83(1986)- 36 47 21. (N) 121 35 19. (W) SCALED GU2036* NAVD 88 - 93.71 (+/-2cm) 307.4 (feet) VERTCON GU2036 ___________________________________________________________________ GU2036 GEOID HEIGHT- -33.15 (meters) GEOID99 GU2036 GU2036 VERT ORDER - FIRST CLASS I (See Below) GU2036 GU2036.The horizontal coordinates were scaled from a topographic map and have GU2036.an estimated accuracy of +/- 6 seconds. GU2036 GU2036.The NAVD 88 height was computed by applying the VERTCON shift value to GU2036.the NGVD 29 height (displayed under SUPERSEDED SURVEY CONTROL.) GU2036.The vertical order pertains to the superseded datum. GU2036 GU2036.The geoid height was determined by GEOID99. GU2036 GU2036; North East Units Estimated Accuracy GU2036;SPC CA 4 - 664,660. 1,768,990. MT (+/- 180 meters Scaled) GU2036 GU2036 SUPERSEDED SURVEY CONTROL GU2036 GU2036 NGVD 29 - 92.846 (m) 304.61 (f) ADJUSTED 1 1 GU2036 GU2036.Superseded values are not recommended for survey control. GU2036.NGS no longer adjusts projects to the NAD 27 or NGVD 29 datums. GU2036.See file dsdata.txt to determine how the superseded data were derived. GU2036 GU2036_U.S. NATIONAL GRID SPATIAL ADDRESS: 10SFF259724(NAD 83) GU2036_MARKER: DB = BENCH MARK DISK GU2036_SETTING: 36 = BRIDGE GU2036_STAMPING: M 1192 1968 GU2036_STABILITY: B = PROBABLY HOLD POSITION/ELEVATION WELL GU2036 GU2036 HISTORY - Date Condition Report By GU2036 HISTORY - 1968 MONUMENTED CGS GU2036 GU2036 STATION DESCRIPTION GU2036 GU2036'DESCRIBED BY COAST AND GEODETIC SURVEY 1968 GU2036'9.3 MI NE FROM SALINAS. GU2036'2.75 MILES NORTH ALONG MAIN STREET FROM THE SOUTHERN PACIFIC GU2036'COMPANY RAILROAD STATION AT SALINAS, THENCE 6.55 MILES NORTHEAST GU2036'ALONG SAN JUAN GRADE ROAD, 8.0 MILES SOUTHWEST OF SAN JUAN GU2036'BAUTISTA, IN THE TOP AND 1.1 FEET SOUTHWEST OF THE NORTHEAST GU2036'END OF THE SOUTHEAST CONCRETE CURB OF A CONCRETE BRIDGE OVER A GU2036'CREEK, 11 1/2 FEET SOUTHEAST OF THE CENTER LINE OF THE ROAD, AND GU2036'ABOUT 1 FOOT HIGHER THAN THE ROAD. *** retrieval complete. Elapsed Time = 00:00:01

Well you don't want us to know where you are so I can't search any database to find it. I need the state.

Parsa quote: The benchmark in question is not shown on my topographic map. It was the radio mast for a radio station (KOWN) in Escondido, CA that no longer exists. The tower was a 150 ft red and white tower with a red light. There is no such tower within miles. Perhaps a disk exists in the ground somewhere, but the coordinates put me in the middle of an industrial building. Even the address on Hale Ave no longer corresponds to the numbering system. To anyone looking for the benchmark in the 60's or 70's, the mast would be obvious, but there's no detailed description to find where it once was. If this is the case and you are without a doubt positive its gone then report it as not found. There is not disk. Often times the surveyors never even visited the location of most these landmarks like radio towers or church spires. Someone from the recon team may ahve gather the info but thats about it. They observed these from thier control stations many miles away for the most part and computed the position by triangulation. That is intersecting them from other point and by solving the triangles, determine position of the landmark.

You asked a lot. May take several years to answer all these questions fully but I will touch of some I know about. 1. Some vertical and horizontal control points are marked (and even named) on my local topos that don't appear on the full "alive and dead" Geocaching/NGS list of benchmarks. The topos aren't incredibly new or old (c. 1970s revision, etc.), so why would that be? Well, if often boils down to when the maps were made. When some were made either the survey infomation was not avaialble to them or someone in charge made a decision that it was not needed on the map. Most of the control information was really not even published until the 70's. Prior to that it was in field books etc and retained by the agency doing the Surveys. The current maps were field checked in some instances and the party doing the work located the marks and marked them on the maps. Also, ones that are not marked could have not been in place at the time of the map. I am sure there is more to this but thats the jist. A lot of the USGS maps for my area were mapped in 1946 and photo revised in the 1970's. 2. What's the difference between a vertical control mark with "recoverable mark" and a spot elevation on the topo map? Both have the elevation and the X on the map. Is one black and one brown? What about the black elevations with no X at all (like at intersections)? A spot elevation is just that, the level party determined an elevation of that point to the closest 0.10 meters to aide in mapping contours and for the map user. The vertical control mark is exact and it monumented, the spot elevation is not monumented. There is a pamphlet available from USGS that describes all the map symbols etc. 3. Why on earth would a contractor or other builder destroy an official federal benchmark for some trivial construction? I'm not talking about a major road widening, I mean like putting in a sidewalk or a horseshoe pit. First of all, its the equipment operator that in all likelyhood was the culprit. They often do not even know they existed and I am afraid to say some just don't care. There are A.H.'s in every profession and would run over your car if it was parked in thier way. I know of instance where poeple found these on property the owned, were afraid of the gov't claiming their land or some other hair brained idea and they destroyed them out of contempt. 4. I went to a major horizontal control mark in my town (the designation is the town's name, Escondido), and it had the main station disk, reference mark Escondido No 1, reference mark Escondido No 2, a post, an azimuth mark, and somewhere there was an underground marker. If I only found the brass circle of Reference No 1, is it a find? It was at least right on the 0.0 point (NAD1983), and seems to exactly coincide with the triangle on the topo. No, I would say not, you only found a reference, No. 1 and No. 2 are reference marks. The main purpose is to locate the control station in the event the surface mark cannot be found. The underground mark is at the same location as the station mark, just buried some ? feet down as a safe gaurd from loosing the station position. The azimuth mark is set for local surveys so as to have a bearing between the station and the azi to base a survey on. Surveying is the science of measuring the land (earth) and that is done by angles, distance and elevation. Most all surveys and property deeds use bearing and distance to locate and describe them. Often called "meets and bounds". Pick up any survey and you will find a bearing on it, S 80 deg 45 min 23 secs W 1240.02 feet, etc. The surveyor can use these 2 points to get on the state plant coordinate system for his state. 5. That leads to a related question. Why are the NAD1983 coordinates often *way* off? Is it only true on the vertical marks? How did they determine coordinate locations for the control points? You have to read the data sheet, it explains a lot. First of all, GPS is only accurate to + or - 100 meters 90% of the time. Hand units while appearing to be right on are not at all accurate for surveying in sense othe than recon. Look at the data sheet and if it says "Scaled" after the lat and lon then it means, the survey crew plotted it on a USGS map and interpolated the position from that. There was no need to conduct a more precise survey for this point, it has only vertical importance but the scaled Lat and Lon could have some value in planning future work or finding your position on the ground. Without a scaled position, it could be anywhere but this pin points its location. Were some control points surveyed and located with more accuracy using astronomical and chronological measurements (such as on meridians)? Yes they were precisely surveyed by various methods, from triangulations to travese to GPS. The data sheet tells you how it was done. Classical Geodetic Methods are triangulation and traverse, while GPS is used exclusively today since the 1980's. 6. Do towers, and structures that act as control points have a disc somewhere, or is it just the structure that acts as the marker? If that structure is obviously nowhere near the coordinates (ex, a tall radio tower), is it "destroyed"? No the towers etc are just landmarks, no disks exist on/in the landmark itself. But if it is a tower such as a old fire lookout lookout tower, it may well have an disk set in the ground under the tower, as often done by USGS to map the exact locations. You can't assume because your coords do not jive that anything is destroyed. Many things come into play here, maybe you have the wrong tower, or a new one was contructed close to the old position, your GPS receiver is not adequate, you have the wrong coord system or something else. 7. If a marker is lost, and then in a later year listed as "recovered" and "good", why does it appear in the "dead" category (with a skull)? Don't know the reason for that but my just be a computer programming error. Also since someone reported it as lost and know it is reported as found, adding doubt. This bears saying, HAND HELD GPS UNITS ARE NOT SURVEY GRADE AND WILL NOT GIVE THE SAME RESULTS. People assume the GPS is right on but that is not true. Its close! but not perfect. Thats why you need a professional surveyor to determine a legal position. If your are off 1 sec in position, that can equte to approx 100 feet on the ground. I have had some real battles with some persons who believe what they see on the hand help GPS reciever is right on the money. Most units are set to work in Degrees and decimals there of. A surveyor would work in degrees minutes seconds, e.g. ddd mm ss.sssssssss to be continued I'm sure...... [This message was edited by elcamino on January 17, 2003 at 10:16 AM.]

many NOS marks are slow to show up in the NGS database. There are several in my area that were set in the 1970's and they are not in there. Depends on the nature of the survey. NOS is part of NOAA