itchytweed

I am in the upper midwest..My GPSr was only seeing 35 and not trying to get 48 & 51 at all. So, I erased the almanac and let the system go through all the numbers for the WAAS birds to locate 48 & 51 and not be satisifed with 35 only. The blocking is only to force the search when the new almanac was received. The unit still has 35 available to use but now looks for 48 and 51 first because their signals are higher up and stronger than 35. The west coast users will get to use 35 and one of the other ones as well. Now to find out if 7 foot accuracy means +/- 7 feet or +/- 3.5 feet on my Garmin GPS V...

You should be able to see the other two sats. The almanac has to be wiped for the new birds to be recognized. Or you can be in WAAS mode and set up a blind so the unit can't see WAAS 35 for some time and hopefully will cycle through the numbers. The whole process for me took about 30-45 minutes. All I did was let it sit still for the time. Good Luck!

From resetting my GPS V, are you using WAAS 35? I have found that since I am now using WAAS 48 & 51, I am now displaying display 9 ft accuracy outside and moving. You may wnat to check to see which birds the CS60 is using.

Procedure for Garmin GPS V (v. 2.5 software): Backup your routes/waypoints/tracks before doing this - they will be wiped out. 1) Cover or disconnect antenna 2) Hold MENU button down during power up 3) Answer "yes" to user reset 4) Go to Setup and turn back on WAAS Processing 5) Uncover or plug in antenna and let it locate satellites. Make sure that satellite #35 is blocked from reception.. 6) Leave on for at least 1/2 hour to get new almanac and adjust itself If all is fine, satellites #48 & 51 should show up in the WAAS section and be used. My testing was displaying 9 ft accuracy readings on the display moving today and on a waypoint averaging session of 45 minutes, accuracy was displayed as 3 ft. I was getting 48 & 51 at full scale today here in So. Wisconsin. This is a good thing....enjoy 73 from 807, Itchytweed

I ditched the sines/cosines process in favor of polar/rectangular conversions. The end result is the same but having the X/Y values is good for tape runs, especially when defining a search area for trying to find an elusive monument. I currently have it set up for three RM's/Azimuth but the spreadsheet can be enlarged to fit any amount of references. An added benefit is that the math is far, far easier. Now to build a website to store it on. Happy, Happy, Joy, Joy.

NMEA sentence $GPRMC has magnetic declination included in it. Now the question is - Is the value from a lookup table that will have to be constantly updated or is it something that is calculated from the satellites and their data streams?

BDT - You hit the process on the button. A spreadsheet would be easy to do and can be put into a handheld, laptop or desktop computer. I was going to make it so that you plug in the angles off the datasheet and the output is angles from True North. I don't have the equipment either for turning angles but converting them to angles from True North is the best way to go about this. I will not deal with declination as this should be compensated for by calculating from True North. Now, once the spreadsheet is done, how to pass it on?

I realize that this may have been covered before elsewhere and I may not have seen it. If agreed upon, I can write another FAQ about using the laws of sines and cosines to get all angles for a station and its associated marks. Here again, I would use my own personal devil, WAUWA, as the example. I have not seen a station that uses a right angle in my area to set the reference and azimuth marks. 5 degrees out and a windchill at -10 F is not conducive to BM hunting and taping off positions so I might as well type and share some knowledge.

Over in Benchmark Hunting, I posted a FAQ offering on how to do just this but not using FORWARD.EXE (windoze only) but a spreadsheet with Vicenty's Equations. I also include a blurb on how to do the routines. I prefer the spreadsheet option because I can tweak if necessary. Take a look.

Cement/concrete is a glue. In time, it will disintegrate on its own from thermal expansion/contraction and other elemental disruptions. Covering up the stations with dirt willl slow down the disintegration but the salt will still work it's way through the soil on snow melt and so will the water. Plus, water has its own little nastiness on its own - its highest density is at around 34 degrees. As it freezes, it expands. IMHO, it would be best to seal the concrete so the infiltration will stop. The sealing will not prevent the expansion/contraction issues but it will prevent the incursion of the deicing compounds, environmentals and water. It can't reverse the damage but it can prolong the life of the station. If the sealing is going to take place, it should be done during the summer after a long, hot and dry spell. All we can do is hope.

Back when I was in college aeons ago, our area was lucky to have a declination of zero. It sure made bushwacking far, far easier. Now where I live, the adj is 3 deg W. Not a big deal, but it is there. There is a joke in there somewhere...about giving the earth a lecture on moving the poles........

Since the parent was posting online dox from the USPSQ, here is one from the Army Corps of Engineers: http://crunch.tec.army.mil Maybe it would be a good thing to add to the FAQ a list of websites that provide documentation involving benchmarks. We can have the USPSQ, Corps of Engineers, NGS, etc.

I have more old BM's around my place than I can shake a stick at. I found one that is older than me and that felt good. This may seem weird but when I lived in California for 14 years, I felt a bit detatched. Being back here in the midwest and doing the looking kind of puts me back into perspective and grounds me (ouch!). Finding some marks are easy - they are out in broad daylight. Others, you have to scrounge around for - I still am recovering from my last foray into the weeds...burrs all over my pants and socks. The descriptions are fun and some of the texts are a great history lesson as well. It a way, we are writing about out society and its history in terms of geospacial relationships and how our society is moving. Keep looking...there is history out there waiting to be discovered.

A followup to the cleaner from my last post. I found, by accident, that "Sparkle" (a window cleaner that I use) removes the dried ink with no problem. If a shadow is left, the eraser gets rid of it.

Only BM's at this time. Currently logging to GC.com for the ones listed on site that I have found or not. I am setting up to send info to NGS for all BM's they have listed that I have found or not.

Here is another offered tidbit - OT but useful. One trick that I learned ages ago is to take heat laminating sheets and put into them a sheet of X-Y ruled paper, my favorite is 10 lines/inch. Seal the paper in without any text on it. Now comes the fun part. I can write on the laminated sheet with permanent marker. Once the ink dries, rain won't take it off. You can erase it using a white vinyl eraser or wipe the whole sheet clean with Goof-Off. The pen will stain the plastic if you leave it on for a long while. These make great reusable worksheets for out in the field.

In my professional job, I have to solve all sorts of applications, installation, programming , design, and troubleshooting issues with our company's equipment. I can sit all day and the job is a no brainer - experience pays off to make it this easy. Sometimes, to the point of boredom, which makes other people really wonder. I have found that in finding benchmarks and noting where they are, my mind is constantly chewing on spatial relationships between the benchmarks. I have found marks that are not listed on this website or the NGS database (WI DOT benchmarks, both task designated and not). Now I take these and use marks that are listed and try to figure out relationships in my head. I have found at least one (my very first one!!!) that when you work out the positions, is very interesting to me. Then again, there is the thrill of the search. An example is trying to find WAUWA AZ MK RESET. I have scouted for this mark all over and have not found it but I found a mark that is not listed in the datasheet for another station, MILWAUKEE GPS. I found an AZ MK for this station and calculated that this new mark could serve double duty, as the AZ MK for MILWAUKEE GPS and it is just about at 270 deg true from where the, as yet, unrecoverd WAUWA benchmark should be. Asides from the mind exercises that are fun, I get outside and moving. I enjoy long distance bicycling for exercise and the walking over unknown territory is just as fun. Happy Hunting!

BDT - Thanks for Zhanna's site. It is well done and full of info. I have relatives in PA so the pix bring back memories.

I know that here in Wisconsin, we have a page, http://sco.wisc.edu/geocat/index.php, that is called ControlFinder. It is a neat little applet that allows you to locate BM's in the state, whether they are county, state, feds, etc. Hopefully other states have something like this in place.

Don't everyone beat me up too hard on this. Go over this and let me know of any issues. And of course, flames > /dev/null. Happy Thanksgiving. ----------------------------------------------------------- STATION / BENCHMARK LOCATING FAQ By Itchytweed – 23 Nov 2005 When I started this process of finding benchmarks/stations, I was revisiting my college days when I was taking classes in surveying. My chosen profession is Electrical Engineering specializing in electrical power control systems. So, as to keep the creative, analytical juices going, I started working with this hobby. I am also an Amateur Radio Operator holding an Amateur Extra License. Conventions used in this FAQ are as follows: Lat/Lon readings will be ddd mm ss.sssss (d/m/s) and ddd.ddddd (decimal degrees) Azimuth angles will be referenced to zero degrees being true north proceeding counterclockwise Compass direction letters will preceed the Lat/Lon readings - N dd mm ss.ssss or W ddd.ddddd This FAQ is to help out a geocacher/benchmark hunter take a NGS Station Report and locate where the benchmarks mentioned are placed in relation to the main station's location. This is based on the current survey control reading for the station and the associated azimuths and distances for the reference marks, as supplied in the NGS Station Report, as offered by geocaching.com and the NGS repository on the web (R.I.P. Craig Larrimore). The below report is for a set of benchmarks near where I live and have not been totally recovered. I have located RM1, along with several others, but not the main station, RM2, Victory PP 1, or the Azimuth Mark Reset. National Geodetic Survey, Retrieval Date = NOVEMBER 20, 2005 OM0754 *********************************************************************** OM0754 DESIGNATION - WAUWA OM0754 PID - OM0754 OM0754 STATE/COUNTY- WI/MILWAUKEE OM0754 USGS QUAD - WAUWATOSA (1994) OM0754 OM0754 *CURRENT SURVEY CONTROL OM0754 ___________________________________________________________________ OM0754* NAD 83(1991)- 43 02 19.27031(N) 088 01 43.75226(W) ADJUSTED OM0754* NAVD 88 - 238. (meters) 781. (feet) SCALED OM0754 ___________________________________________________________________ OM0754 LAPLACE CORR- -3.28 (seconds) DEFLEC99 OM0754 GEOID HEIGHT- -34.92 (meters) GEOID03 OM0754 OM0754 HORZ ORDER - THIRD OM0754 OM0754.The horizontal coordinates were established by classical geodetic methods OM0754.and adjusted by the National Geodetic Survey in November 1991. OM0754 OM0754.The orthometric height was scaled from a topographic map. OM0754 OM0754.The Laplace correction was computed from DEFLEC99 derived deflections. OM0754 OM0754.The geoid height was determined by GEOID03. OM0754 OM0754; North East Units Scale Factor Converg. OM0754;SPC WI S - 117,286.482 760,608.447 MT 0.99995246 +1 21 15.9 OM0754;UTM 16 - 4,765,624.393 416,194.885 MT 0.99968640 -0 42 07.9 OM0754 OM0754! - Elev Factor x Scale Factor = Combined Factor OM0754!SPC WI S - 0.99996817 x 0.99995246 = 0.99992063 OM0754!UTM 16 - 0.99996817 x 0.99968640 = 0.99965458 OM0754 OM0754: Primary Azimuth Mark Grid Az OM0754:SPC WI S - WAUWA AZ MK RESET 267 16 18.6 OM0754:UTM 16 - WAUWA AZ MK RESET 269 19 42.4 OM0754 OM0754|---------------------------------------------------------------------| OM0754| PID Reference Object Distance Geod. Az | OM0754| dddmmss.s | OM0754| OL0412 W MILWAUKEE CHAIN BELT CO STK APPROX. 5.3 KM 1224030.0 | OM0754| OL0403 MILWAUKEE FROEDHERT MALT ELEV APPROX. 6.5 KM 1252040.1 | OM0754| OM0759 WAUWATOSA MUNICIPAL TANK 5 APPROX. 1.3 KM 1290146.8 | OM0754| CJ7903 VICTORY PP 1 37.795 METERS 20318 | OM0754| CJ1628 WAUWA AZ MK 2575352.1 | OM0754| CJ1629 WAUWA AZ MK RESET 2683734.5 | OM0754| CJ1631 WAUWA RM 2 23.393 METERS 27057 | OM0754| CJ1630 WAUWA RM 1 23.314 METERS 35900 | OM0754|---------------------------------------------------------------------| OM0754 OM0754 SUPERSEDED SURVEY CONTROL OM0754 OM0754 NAD 83(1986)- 43 02 19.25969(N) 088 01 43.76376(W) AD( ) 3 OM0754 NAD 27 - 43 02 19.21000(N) 088 01 43.44600(W) AD( ) 3 OM0754 OM0754.Superseded values are not recommended for survey control. OM0754.NGS no longer adjusts projects to the NAD 27 or NGVD 29 datums. OM0754.See file dsdata.txt to determine how the superseded data were derived. OM0754 OM0754_U.S. NATIONAL GRID SPATIAL ADDRESS: 16TDN1619565624(NAD 83) OM0754_MARKER: DO = NOT SPECIFIED OR SEE DESCRIPTION OM0754_SETTING: 7 = SET IN TOP OF CONCRETE MONUMENT OM0754 OM0754 HISTORY - Date Condition Report By OM0754 HISTORY - 1953 MONUMENTED CGS OM0754 HISTORY - 1961 SEE DESCRIPTION CGS OM0754 HISTORY - 1963 SEE DESCRIPTION CGS OM0754 OM0754 STATION DESCRIPTION OM0754 OM0754'DESCRIBED BY COAST AND GEODETIC SURVEY 1953 (ELJ) OM0754'STATION IS LOCATED ON THE SOUTHWEST CORNER OF THE GROUNDS OM0754'OF THE MILWAUKEE COUNTY INSTITUTIONS IN THE SOUTHWEST SECTION OM0754'OF WAUWATOSA AND ON THE NORTH SIDE OF WEST WISCONSIN AVENUE OM0754'AT THE INTERSECTION OF 93RD STREET. IT IS 150 FEET SOUTHWEST OM0754'OF THE SOUTH END OF A BRICK BUILDING, 124 FEET NORTHEAST OM0754'OF THE INTERSECTION OF WEST WISCONSIN AVENUE AND 93RD STREET OM0754'AND 5 FEET WEST OF A WHITE WITNESS POST. THE MARK IS FLUSH OM0754'AND THE DISK IS STAMPED WAUWA 1953. OM0754' OM0754'REFERENCE MARK NO. 1 IS 83 FEET SOUTHWEST OF THE SOUTH END OM0754'OF THE BRICK BUILDING AND 5 FEET WEST OF A 16 INCH MAPLE OM0754'TREE. THE MARK IS FLUSH AND THE DISK IS STAMPED WAUWA NO OM0754'1 1953. OM0754' OM0754'REFERENCE MARK NO. 2 IS 116 FEET NORTH OF THE INTERSECTION. OM0754'THE MARK IS FLUSH AND THE DISK IS STAMPED WAUWA NO 2 1953. OM0754' OM0754'AZIMUTH MARK IS 43 FEET SOUTH OF THE CENTER OF WEST WISCONSIN OM0754'AVENUE, 23 FEET WEST OF THE CENTER OF 95TH STREET AND 2 OM0754'FEET SOUTH OF A FENCE CORNER AND WHITE WITNESS POST. THE OM0754'MARK IS FLUSH AND THE DISK IS STAMPED WAUWA 1953. OM0754' OM0754'TO REACH THE AZIMUTH MARK FROM THE STATION, GO WEST ON WEST OM0754'WISCONSIN AVENUE FOR 0.2 MILE TO THE INTERSECTION OF 95TH OM0754'STREET AND THE MARK ON THE LEFT AS DESCRIBED. OM0754' OM0754'HEIGHT OF LIGHT ABOVE STATION MARK 26 METERS. OM0754 OM0754 STATION RECOVERY (1961) OM0754 OM0754'RECOVERY NOTE BY COAST AND GEODETIC SURVEY 1961 (CJB) OM0754'THIS STATION WAS RECOVERED AS DESCRIBED AND ALL MARKS WERE OM0754'FOUND IN GOOD CONDITION. WISCONSIN HIGHWAY DEPARTMENT OFFICIALS OM0754'THOUGHT THE AZIMUTH MARK FOR THIS STATION WOULD BE DISTURBED OM0754'BY ROAD CONSTRUCTION ALONG AN EXPRESSWAY WHICH PASSES UNDER OM0754'WISCONSIN AVENUE JUST WEST OF THE AZIMUTH MARK. THIS WEST OM0754'EXPRESSWAY HAS BEEN BUILT AND THE AZIMUTH MARK IS STILL OM0754'IN PLACE. THE MARK PROJECTS 4 INCHES AND THE DISK IS STAMPED OM0754'WAUWA 1953. OM0754 OM0754 STATION RECOVERY (1963) OM0754 OM0754'RECOVERY NOTE BY COAST AND GEODETIC SURVEY 1963 (VRS) OM0754'RECOVERED ALL MARKS IN GOOD CONDITION ESSENTIALLY AS ORIGINALLY OM0754'DESCRIBED, EXCEPT THAT THE ORIGINAL AZIMUTH MARK IS DESTROYED. OM0754'A RESET AZIMUTH MARK WAS ESTABLISHED AT THIS TIME. OM0754' OM0754'ABOUT 6 MILES DUE W OF THE HEART OF DOWNTOWN MILWAUKEE, ABOUT OM0754'THREE-QUARTERS OF A MILE N OF INTERCHANGE BETWEEN EAST-WEST OM0754'EXPRESSWAY (INTERSTATE 94) AND WEST EXPRESSWAY (INTERSTATE 894), OM0754'0.2 MILE E OF THE LATTER, ON S SIDE OF THE EXTENSIVE GROUNDS OM0754'OF MILWAUKEE COUNTY INSTITUTIONS, 129 FEET (SLOPE) NNE OF OM0754'INTERSECTION OF CENTER LINES OF WISCONSIN AVE. AND 93-RD OM0754'STREET, 150.4 FEET SSW OF SSW EDGE OF CIRCUMFERENCE OF STONE OM0754'WINDOW LEDGE OF CIRCULAR END OF SW WING OF INSTITUTIONAL OM0754'BRICK BUILDING, 21 FEET W OF PROJECTED PLANE OF W WALL OF OM0754'2-STORY BRICK BUILDING ON S SIDE OF WISCONSIN AVE., ON TOP OM0754'OF A BUMP IN THE INSTITUTIONAL LAWN, STANDARD DISKS STAMPED OM0754'WAUWA 1953, ARE SET IN 1A AND 7A MARKS, FLUSH. OM0754' OM0754'REFERENCE STAMPED WAUWA NO 1 1953, NOTE 11A, FLUSH, IS 76.49 OM0754'FEET OR 23.314 METERS N IN AZIMUTH 179 DEG 00 MIN FROM STATION, OM0754'107.2 FEET SW OF SW END OF NW STRAIGHT-LINE WALL OF SAID OM0754'BUILDING SW WING, AND 0.9 FOOT SE OF PROJECTED PLANE OF OM0754'SAID NW WALL. OM0754' OM0754'REFERENCE STAMPED WAUWA NO 2 1953, NOTE 11A, FLUSH, IS 76.75 OM0754'FEET OR 23.393 METERS W IN AZIMUTH 90 DEG 57 MIN FROM STATION, OM0754'116 FEET N OF CENTER LINE OF WISCONSIN AVE., AND 35.3 FT. OM0754'NW OF PROJECTED PLANE OF NW WALL OF SAID SW WING OF THE OM0754'BUILDING. OM0754' OM0754'AZIMUTH MARK STAMPED WAUWA RESET 1963, NOTE 16B, FLUSH, IS OM0754'ABOUT 0.15 MILE W IN AZIMUTH 88 DEG 37 MIN 33 SEC FROM STATION, OM0754'ABOUT 90 YARDS E OF CENTER LINE OF NO. 894 HWY., 95 FEET OM0754'N OF CENTER LINE OF WISCONSIN AVE., AND 1.0 FEET NE OF CYCLONE OM0754'STEEL FENCE. I am a fan of using Decimal Degrees in my calculations. My Garmin GPS V offers decimal degrees, degrees/minutes, and degrees/minutes/seconds. In comparing the accuracy between all three modes, I found that the smallest positional increment that can be displayed is decimal degrees (to five decimal places). I realize that the GPS unit may not be that electronically accurate, but dealing in decimals is far easier computationally that deg/min/sec. So, to each his own. To make life easier, grab the following spreadsheet off of the internet: vincenty.xls. I picked up the sheet from ftp://surveying.wb.psu.edu/vincenty.xls. I know that there are other repositories for the sheet as well, in different forms. It is an Excel spreadsheet that is coded to perform both of Vincenty's equations, direct and inverse. This spreadsheet will work in OpenOffice Calc as well, which is what I use under Linux. Vincenty's Direct equation takes a known point and with an azimuth line direction and distance in meters, will output lat/log of the projected point. Vincenty's Inverse equation takes the lat/long of two points and supplies the bearing lines and distance in meters. I modified my copy of the sheet to work with decimal degrees but for this FAQ, I will stick with d/m/s. From the NGS datasheet, we know that the WAUWA station is at N 43 02 19.27031, W 088 01 43.75226. This translates into N 43.03869 W 88.02882. Using Vincenty's Direct, I put in the Lat/Lon of the WAUWA station. From looking at the box that lists “ PID / Reference Object / Distance / Geod. Az”, let's calculate the Lat/Lon for WAUWA RM 1. From the listing for RM 1, the distance is 23.314 meters, azimuth (d/m/s true) is 359 00 00.0. Using the DIRECT sheet, plug in the station location in d/m/s and the meters and azimuth to RM 1, the sheet answers back as N 43 02 20.02569 W 88 01 43.77024. Now, I found that column A of the sheet has the locations show/calculated in decimal degrees :-). That makes my life easier so it reads N 43.03890 W 88.02883. West Longitude is indicated by a negative number and I would expect South Latitude to be the same, being a negative number. Now we can perform the same for the WAUWA Azimuth Mark Reset. You will note that there is no reference to distance in the box. This takes a bit of reading to determine. The latest description reads “... about 0.15 mile W in azimuth 88 deg 37 min 33 sec from station...” Let's, for the sake of the exercise, accept 0.15 mile as being usable. 0.15 miles = 241.4016 meters. Adding 180 degrees to the listed azimuth from Az Mk Reset gives us 268d 37m 33s. Plugging in the values gives us N 43 02 19.08257 W 88 01 54.41366, or in dec. deg: N 43.03863 W 88.03178. You can continue with this procedure to index all the associated markers with the station. I have not discussed what Vincenty's Inverse sheet is for. You put in two points described in d/m/s and the result will be azimuth directions and distance in meters. On both sheets, I put in processes to convert decimal degrees to d/m/s for entering into the spreadsheets. With a little rearranging, other solutions can be found. If you find a reference mark, you can backtrack the same way and get to the main station or any other station, as long as you know the coordinates of the benchmark that you are using and the distances/azimuths to the other benchmarks/stations. I know that there are several shareware/freeware/$ware software packages that work under Windows to achieve this with many more bells and whistles. This spreadsheet runs on anything that accepts Excel spreadsheets. It may not be neat and fancy but it gets the job done with little toil. In testing, WAUWA RM 1 was found within the error of the GPS. Happy Hunting.

I will try to finish it up this weekend. Even though I may be home from the salt mines for the next four days for the Thanksgiving holiday, my time is pretty much booked. Bill93, I will post the FAQ and I will let you work my answers through the NGS Tools, if you please. We can call it Peer Review...always a good thing. I don't run my IBM T42 on the web under WindowsXP. I have been a Linux devotee for many, many years and I am far safer being on the wild, wild web with Linux. I prefer the spreadsheet way because it allows for modification and scratchpad operations on-the-fly. Now to grab a hot cup of fresh joe, check on the children, and back to the wordsmithing. -- Itchytweed

I am new to benchmark finding. While trying to get the hang of it, I managed to come up with a simple procedure to take the info from datasheets and using Excel to determine RM/AZ coord's from the description on the sheets and the location of the main station. I do not know if a procedure or info exists here on the forum. If it does not, I would be glad to put up the process and where I got the .xls sheet from that I used as the aid. Now that the snows have returned to the midwest , we will just have to continue on. It will be just like I was back in college and when I took my surveying course (non-CE's had the winter class). For some weird reason, we would always have heavy snows on the days that we were scheduled for an outside field party. Ah, the joys of the younger days. -- Itchytweed