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Question about LIDAR and ArcPro

Question asked by ANichols_ptbo on Aug 1, 2018
Latest reply on Aug 2, 2018 by MKennedy-esristaff

Hello there

 

I recently acquired some Lidar of my municipality and have a few questions about how to go about best using it. The LIDAR is currently classified into bare earth, low, medium and high vegetation.

 

In the summary sheet that came with the data, it says that the LIDAR is projected to NAD 83 CSRS (2010) UTM ZONE 17N. However, when I bring it into ArcPro (version:2.2.1) and look at the Spatial Reference section in the properties, the .las files are not projected and have an unknown coordinate system.

 

I was successfully able to use the "Define Projection" Tool to assign NAD 83 CSRS (2010) UTM ZONE 17N to the files, and they rendered in the appropriate spot in my scene. Next I used the "Set LAS Class Codes Using Features" tool with 2d building footprints to separate points into Classification 6 (Buildings). But it didnt quite work as I expected, or rather I didn't notice anything happen. When I change the LAS Filter to Classification 6 (Buildings), nothing renders, I just see the red box. All of the other classifications (bare earth, low, medium, high vegetation) work just fine.

 

For fun, I used the "Define Projection" Tool again and used the normal NAD 1983 UTM ZONE 17 N projection. Again I used the "Set LAS Class Codes Using Features" Tool with 2d building footprints. This time, IT WORKED! When I changed the LAS Filter to Classification 6 (Buildings) it worked perfectly and I could clearly see the buildings point cloud.

My goal is to use the ArcGIS Solution "Local Government 3D Basemaps" and generate 3d building models from the LIDAR. I ran the test data projected in the normal NAD 1983 UTM ZONE 17 N through the "Local Government 3D Basemaps" tasks and everything looks good. The resulting multi-patch models have correct heights, roof types etc and I feel confident in the results.

 

Does anyone have advice about this issue? Should I continue with normal NAD 1983 UTM ZONE 17 N projection, even though the LIDAR was collected in NAD 83 CSRS (2010) UTM ZONE 17N? What kinds of issues could I run into?

 

edit: Location is City of Peterborough, Ontario Canada.

 

Thank you. I appreciate your time!

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