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The German Wikipedia explains also a closed form solution for the four sphere equations: https://de.wikipedia.org/wiki/GPS-Technik#L.C3.B6sungsverfahren_f.C3.BCr_4_Gleichungen_mit_4_Unbekannten However, I don't know whether it is actually used by current GPS Receivers.


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There are two versions that I was taught on a GPS course (admittedly a lot of years ago): take partial differential equations of the distance equations (with an unknown time error) a closed form solution by Steve Bancroft (which I knew as the "King Radio" method, but since King got absorbed by Bendix, then by some other avionics manufacturer, that ...


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Disclaimer: Any method you use to do this, especially with a consumer GPS unit, is going to be an approximation at best. If you truly want to know where the boundaries are, you will need to locate property pins/corners which might require a metal detector. Your best, safest option is to hire a professional land surveyor. No, those are not lat/longs in the ...


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I would suggest you to try gdal2tiles.py gdal2tiles.py --force-kml --webviewer=none [input file] [output_dir]/ Would create a directory with all tiles and the KML file. Simply compressing it into a ZIP file and changing the file extension to .kmz gets you a KMZ file ready to put onto your GPS device. You could also script the whole process in bash: for ...


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Short answer, use the DEM. Handheld GPS units of the type you mention (consumer grade), can potentially use two different methods to figure elevation - the calculated GPS position or an internal barometric altimeter. Because of the way GPS works (explained at the page mkennedy originally linked to in a comment, and elsewhere), without high-grade, corrected ...


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Provided that the line segments have ObjectIDs numbered in the same order as the points and all points have sequential ObjectIDs, you can add a field called EndOID to your lines and calculate it to be equal to ObjectID + 1. Also add two dateTime fields called Start_Time and End_Time and a double field called Duration to your lines. Do a standard join of ...


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It could be that depending on the software that you use to do the sum, if one vehicle has no data, then the final sum is invalid. As a simple workaround, you can set value to 0 (zero) for those cars/trucks without data and then do the sum. This workaround is not helpful if you want to know which car did not travel on a specific date.


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try something like this: calculate the orientation of your polylines in degrees, example: e.g. in the ArcGIS Field Calculator: 180+math.atan2(( !Shape.firstpoint.X! - !Shape.lastpoint.X! ),( !Shape.firstpoint.Y! - !Shape.lastpoint.Y! ) ) * (180 / math.pi ) convert your road network to road vertices (points) and import to PostGIS. apply matching algorithm: ...


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Still having trouble converting SHP to GPX, had it work once and ever again. I created the name field (seen below) and copied the folder into my Garmanin 64 via copy and past but it shows up blank. The one time it worked was with random points, now I am trying to get it to work with a grid In the post above I checked skip attribute creation and forced gpx ...


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You can also write your ssf file to a shapefile directly in TerraSync. This shapefile can then be transferred from the device to your PC. The steps for doing this are as follows: When finished collecting data in TerraSync close out the data file. Open the file manager in TerraSync. (Data>File Manager) Select the data file you want to write to a .shp Tap ...


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Have a look at this tutorial. It may be able to help you out. Also, depending on how you are getting the data, you may have built in ways to convert it. For instance, if you're reading the NMEA stream via something like a Trimble SDK, they usually have converters in there. I also remember that if you're using a .NET program, there were numerous ...



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