We're breaking in a network rover and trying TopSurv 8. I'm trying to wrap my mind around whether I imported something incorrectly, or I just need to adjust procedures.
Network Rover (HiperII) is set to SPC Indiana West, datum=NAD 83_NoTrans, geoid 09' for a project. Small boundary, site is about 200'x800' Shot in some monuments from previous surveys which checked well. Then in office, rotated, translated old coordinates to my new SPC's from rover, and calc in a new boundary. My calc points are at zero elevation by default in my cogo program.
When I load in my calc points (should still be SPC since I calc'd from SPC and did not scale to ground) I call them SPC In West, NAD83_NoTrans, geoid 09', and but it "adjusts" the coordinates of my zero elevation points. I think I get this, it's converting to SPC at zero elevation which is scaling the coordinates.
If I want to run SPC and stake out in SPC, can I get around the zero elevation issue? I can give them all an average elevation for the site I guess and just rely on the geoid.
Anyone care to comment on how they handle this?
Adjusts how? Is it altering the scale? It should just calculate an ellipsoid height based off the zero elevation. Howeve, since you are on a RTN it will show a cut from the true elevation to zero. I would suggest using an assumed elevation that's relatively close to the average height of the area.
Appears you are using the command TopsSurv Cogo >Adjust >Translate >By Coords/Pts. This will translate N,E, and Elevation of all points. To maintain the local elevations try
Cogo >Adjust >Translate >By Az,Dist,Ht and leave the Ht at zero. Not as simple, since you will have to calc the Az and Distance from coordinates, but this will hold your zero elevations.
Or you can try using TopSurv >Cogo >Adjust >2D Transform
Also to reverse it and have the SPC coordinates shown in local datum (this is not permanent adjustment, can go back to SPC), try this method. TopSurv >Configure >Coord. System, toggle OFF "Use Grid/Ground". Now press the button directly to the right with three dots in it. Change Parameters to Origin. Pt. Then enter in your Az Rotation, Orig Point and Ground Pt. The software will convert grid to ground. To go back to SPC got to TopSurv >Configur >Coord. System, toggle OFF "Use Grid/Ground".
FYI: You can try all of these on your PC with TopSurv's PC version. For each version of TopSurv you own on a handheld you can install and license it on a PC for free. Just download and install the PC version, and send the Device ID to your Topcon dealer AND THEY WILL LICENSE the same modules you own for the handheld.
Lee Green