So, we generally use the .dxf output for contours (.10") and generate surfaces for quantities. Usually, we compare those to proposed grading. Pretty straightforward. Anyway, I have field crews take shots with GPS to cross-check the accuracy of data. I generally see decent results but noticed a couple of areas where GPS shots were over 3-4’ off (vertically) to contour surface file. Also, there was an existing wall in place where the contoured surface shows a rounded off slope. It should’ve been closer to veritcal. Next, I brought in the .LAS file from both steps 2 and 3 for another comparison. To my surprise, the .LAS files were very different compared to the contours. Again, we contour these at .10’. While I expect some variance, this is extreme. Example attached.
Anyone ever compare generated .dxf files to .LAS files?
I’ll add this:
Step 1 is done to full rez. We do use GCP’s. This was a a large job around 50+ acres. Think we set 8-10
Step 2 mostly default settings with LAS file generated.
Step 3 default with dxf generated at .10’ Grid spacing changed to 50cm
Flown with P4P, GCP’s set with Topcon Hyper+ RTK
Doc3.pdf (635.4 KB)