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Wild T2

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Everything posted by Wild T2

  1. I have never used this program (never had a need to), but it is my understanding that it can translate to and from just about every datum, map projection, and coordinate system that you are likely to encounter in the world. http://earth-info.nga.mil/GandG/geotrans/
  2. The old USC&GS used a lot of what they callled a "four foot stand" in areas where a taller tower was not needed. On rain days when they otherwise could not work they could build these in their camp. They obviously last a long time out in the desert. As previously mentioned they could hold survey instruments or target lights. Here is a photo of one that is not so weathered from the NGS web page... http://www.photolib.noaa.gov/historic/c&gs/theb1606.htm
  3. More about the first geodetic GPS receiver from the Smithsonian... http://americanhistory2.si.edu/surveying/o...rdnumber=997498 Same type used in the 1984 survey I mentioned above.
  4. My first GPS project was in the winter of 1983-1984. We set the concrete monuments in November and December. The GPS work was contracted out to a company called GeoHydro. The head of the company was formerly the head of NGS. The antennas were huge things that looked like a metal plane table about 3 foot square with an antenna in the center covered by a clear plastic dome. The rest of the receiver completely filled the back end of a full size station wagon. It drew so much power that you had to keep the vehicle running, which was not a problem since it was February. I think that we got the results around May 1984 so this thing was of no use in navigating to a mark. Since NOAA has commissioned officers in the NOAA Corps they may have had access to military receivers if they existed at the time.
  5. A firearm can protect you from the snakes that you can see. Snakeproof leggings can protect you from the snakes that you don't see. They also work great for walking through briers.
  6. I work as a surveyor for DNR so I am familiar with our old project in the area. It was a feasibility study with the Army Corps of Engineers to study the potential for new levees to protect the cropland from flooding, and do some environmental restoration as well. We recovered the NGS control, set some new control of our own, did aerial photography for mapping, and did some other on-the-ground surveying. We gave our data to the engineers at the Corps for preliminary review and study. As it turned out, the benefit cost ratio was just a little better than 1 to 1 and the project was dropped. Hopefully our control will still be there when someone in the future decides to re-study the area.
  7. In that Greenfield Bayou area of Vigo County you may come across a bunch of Indiana DNR disks from the 1990's. http://img.Groundspeak.com/user/9e8e3100-3...2b60fcd7c12.jpg http://img.Groundspeak.com/user/dbe9d4ee-7...f18b030fb9b.jpg
  8. A shapefile is actually several files with the same filename but different extensions. I think that there can be up to seven computer files that make up an ESRI shapefile. They all need to be together in the same sub-directory or folder. At a minimum, there are three files to a shapefile; filename.shp, filename.shx, and filename.dbf. ESRI's own free GIS viewer is here... http://www.esri.com/software/arcexplorer/index.html
  9. If you look at the lower left corner of a USGS quadrangle you will see the "credits" for the map. Today we would call this metadata, which is data about the data on the map. It will list the agencies whose control is plotted on the map. At least in my area you can make a pretty good guess as to who set the mark. If you have a line of levels along a railroad or highway where every bench mark is shown with an "X BM ####" with the #### being the nearest foot elevation it is probably NGS or its predecessor the USC&GS. These should be in the database here. If you have a line of levels along a railroad or highway where there are "X BM ####" and "X ####" marks then it is probably USGS or another agency and not likely to be in the Geocaching database. The "X ####" marks are something other than a bench mark disk such as a chiseled square or some other physical mark. If it is an italic X #### it is a spot elevation with no recoverable mark on the ground.
  10. I wish I would have seen this earlier. The dedication is today. http://www.ngs.noaa.gov/News/WrightBros/Program.pdf
  11. I seem to recall that the Interstate Highway System was to have a maximum grade of only 4% (4 foot rise or fall in 100 feet). But there were places where that was not economically feasible, so it didn't happen. I don't have my references handy, but I think that a 9% grade is the maximum for a highway that receives Federal funding. I bet that there is a process to get a variance from this requirement, but I suspect that it is a very difficult process. The steepest main-line railroad grade in the country is in otherwise flat Indiana. Its just under 6%. http://www.oldmadison.com/madview2.html
  12. Here is a good explanination of horizontal accuracy. http://gpsinformation.net/main/ngs-accuracy.html
  13. The triangulation stations and elevation bench marks were frequently set to "read from the road" if they were along a road or railroad. That is, if you walked to the mark from the road, the disk would be oriented for easier reading. If in the middle of nowhere, they were frequently set to "read from the south". I don't think that this was documented in their rules anywhere, just a common practice. At least it seems to be the general practice for NGS marks in my area.
  14. The folks at JPL and other agencies are monitoring movement in Southern Calafornia. http://milhouse.jpl.nasa.gov/index.html
  15. No coordinates, but the Clarksville Indiana marks are in the Falls of the Ohio State Park. Here is a map. http://www.in.gov/dnr/parklake/maps/fallsohio_trail.pdf There is a small disk near the historical marker at the Clark Cabin Site and boat ramp. Access to the boat ramp may be a problem. http://www.in.gov/serv/presscal?PF=dnr&Clist=11&Elist=81518 The big disk is near the sign for the Interpretive Center. More and other info at… http://www.fallsoftheohio.org/
  16. If all it took for another agency that set bench marks to submit it to NGS was a brief note about what was set and the position/elevation data they would submit it and it would be in the database. If that was all it took, there would be a lot of very bad data in the NGS database that could lead to serious trouble. NGS has such high standards for the quality of the data about their survey marks that other federal and state agencies typically do not submit data in the rigorous NGS quality format.
  17. Interesting project, and its nice to see some Washington bigwigs doing some real work for a change. But I must disagree with them about it being the "first" underwater geodetic marker. It may be the first mark intentionally set underwater, but there are probably hundreds or thousands of marks that were set in flood plains that are now underwater due to the construction of dams.
  18. Harmonie State Park together with the historic sites in nearby New Harmony. http://www.in.gov/dnr/parklake/parks/harmonie.html http://www.newharmony.org/
  19. We have paper copies where I work. I don't think that they are on the web. I have looked too. The USGS Water Resources Division office in your state might be the place to start. http://water.usgs.gov/local_offices.html Or http://ask.usgs.gov/ I doubt that very many have been tied in by NGS. If they were working in the area they might tie in the USGS marks and publish them instead of setting their own disk on the structure.
  20. Here is a sample description of a gaging station with multiple disks. They are vertical (elevation) references only. The water resources guys at USGS are a little brief in their descriptions. I wish that they would go into more details when they set multiple unstamped disks at a gage. http://img.Groundspeak.com/user/1e40cfbf-9...bcd0a00ddd0.jpg http://img.Groundspeak.com/user/91b30514-f...f88ba35ee3c.jpg
  21. USGS frequently set several disks and chiseled marks at their gaging stations. If it is in the right part of the structure and the distances and directions to nearby objects match the description you found the mark. Just last week I helped another surveyor with a disk at a gage where there were three disks and I think some chiseled marks.
  22. Triangulation, trilateration, traverse, and GPS are all just methods to establish horizontal control. GPS is the main method today. Not exact textbook definitions, but simply put. Triangulation was mostly measured angles with a few measured distances. Trilateration was mostly measured distances with a few measured angles. Traverse is a series of measured distances with measured angles at each angle point. Triangulation and trilateration are still used by surveyors somewhat, but traverse is alive and well and used in areas where GPS will not work like under tree canopy or places like this… http://www.leica-geosystems.com/media/new/...gotthard_en.pdf
  23. You may find a concrete footer with a square hole in the middle left by the long gone wood post. If the old description calls for a wooden witness post, and there is a steel or modern Carsonite© post at the mark look at the base of the post. The replacement posts were frequently set in the square hole in the concrete. The azimuth mark for station TOTO (ME2359) in northern Indiana, set in 1948, still had a white wooden witness post in 1984. It was either well taken care of by the property owner, or replaced by the owner. It is the only one I have ever seen in Indiana.
  24. I recently did an elevation accuracy assessment using a Garmin GPSMap 76. I observed points at the same elevation 35 times. Here are the results… Count: 35 Mean: 761.49 Maximum: 777.00 Minimum: 753.00 Range: 24.00 Variance: 35.67 Standard Deviation: 5.97 Conditions were more-or-less wide open skys, WASS differential corrected, and at different times of the day over several days. I think that using the GPS for X and Y and an inexpensive laser level for Z would work out better than GPS only for X, Y, & Z.
  25. This may not be of much help, but the Minnesota DNR has a free program where you can upload and download map data to several Garmin GPS units. The Rhino 120 is not on the list that they say work, but at least it is not on the list that they say do not work. The biggest hurdle will be finding the trail data in the right format (ESRI Shapefile), as it may not exist. The shapefile will not appear as a background map in the Garmin. It loads into the GPS as a track log. http://www.dnr.state.mn.us/mis/gis/tools/a.../DNRGarmin.html Try mining for shapefile data at the geography network. http://www.geographynetwork.com Also some links to some State data clearinghouses. http://www.nsgic.org/related_sites/index.cfm Complicated and not very user friendly, but its free.
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