I’m using an Emlid Reach RS+ base and rover set to NAD83 2011 per my state’s NTRIP caster to shoot GCPs. I’ve done all the trouble shooting in the field that I can think to do and I’m still getting absolute accuracy of .3 m or so horizontally and .01 vertically when I process. My most recent effort was shot in the Ohio South coordinate system. I was able to input the proj4 code and images processed without error. I’m getting a consistent distortion pattern on my five points. If the base is located somewhere near the middle of the field, the four corner points are pulled toward the base, vertically, and pushed outward from the base horizontally. My center point, which is located closest to the base, is about dead on each time. I’ve read through all of the documentation pages and I can’t find a solution to this problem.
Gladly!
Proj.4 string is taken from EPSG.io:
+proj=lcc +lat_1=40.03333333333333 +lat_2=38.73333333333333 +lat_0=38 +lon_0=-82.5 +x_0=600000 +y_0=0 +ellps=GRS80 +units=m +no_defs
I’m using the webODM Lightning dashboard app. I create a new project, select the images and the GCP file. The GCP file is created with your GCP Editor Pro. Let me show you the pictures of the points from the GIS software. My base station is located closest to point 3. As you can see, point 3 is within the acceptable margin of error. Points 1 and 2 are to the north of the base station and positioned to the west and the east respectively. Points 4 and 5 are to the south of the base station and to the east and west respectively. I also get this kind of distortion no matter what my GNSS settings on the units. Do you know what’s causing this?
Is there someone who is getting good results able to put a workflow together? I’m happy to put my entire equipment list and workflow up if it would help resolve this issue.
There’s the link to the images, the GCP file, and the survey file from my Emlid unit.
I’m running a Mavic 2 Pro on Drone Deploy’s capture app. Ohio’s NTRIP service is based on NAD83 (2011) and NAVD88. I have those selected in the Reachview app for the survey. Please let me know if you need any additional information and thank you very much for your help!
I just like knowing what I’m comparing my output to, and it helps me test a theory about constraining the --gps-accuracy flag with the results of a prior processing run.
Thank you for taking the time to add more data/info for us!
