GCP coordinate system for processing
Thank you for the many responses
To clarify, we dont have a program we use yet. Right now we have a free trials including pix4d. The program is seeming to fail so we didnt know if the coordinates difference is the problem.
Thank you Bill. Yes my SPC coordinates are in NAD83.
Lee green may have nailed it. My SPCs are in sFT, my drone is native to metric. We may be setting pix4d with the wrong systems hence why it is showing up on the wrong continent.
Thanks for all feedback. I will make some adjustments and go from there. Keep you posted!
The drone I would assume is collecting positions autonomously. It's just standard photo coordinates from the drones on board gps. This isnt RTK, just your normal DJI drone.
Yes, as harris said, my collector is probably collecting in whatever is native, but I have the projection set to SPC so it displays the results in SPC, I can display those in whatever projection or system so getting the coordinates now in any needed form is no issue.
Pix4d makes it a bit confusing by requiring the end user to define the input datum from pictures created by the drone. The software should know by default the drone model that the input is always metric WGS84 Lat, Lon, Ellip. Then the output coordinates are user defined as cartesian coordinates Y,X,Z in USft for most US projects. The software does try to identify the SPC zone, but often gets it wrong.
In Pix4dD the import of the images with be WGS. You can select the output coordinates to whatever system you want. Pix4D won't "fail" - I assume you are selecting ( assigning) the pictures to NAD83 on the import, which is causing your error.
I am compiling for an upcoming presentation the datum handling transoformations inside popular software engines. I do not own Pix4D, so this is an area of weakness. Can anyone tell me specifically, what transformation is the DEFAULT "WGS84-NAD83" transform embedded in Pix4D. Are there options to change the DEFAULT, and if so, what datum transformations are available. If this could be done with a screen grab, that would be great, but I'm really interested in the actual parameters (3 or 7) if they are exposed. The name of the transform is just as important, since software companies use a variety of names. For example, Pathfinder Office or Trimble Business Center calls the NULL transform NAD83(CONUS) or NAD83(Alaska). Exposing the Coordinate System library does expose the parameters 0,0,0.
thanks - You'll get credit on a slide at the upcoming www.aksmc.org conference in Alaska (Feb 13-17).
I used carlson's photogrammetry online software and it worked like butter.
It only asked my GCP datum and what I wanted my output datum to be. No errors. Gave a very nice looking ortho and point cloud. GCPs solved good and were a snap to do.
Now to go back and try Pix4d again, a few others, and then to sample test the processed results.