I have Lidar data, ground points and first returns. I have processed it and have ready tiles from which I am trying to build 3D building models.
So far I was able to just extrude the buildings in the ArcScene and that is it.
I am a beginner in GIS/Remote Sensing and any help would be highly appreciated.
Also, I am trying to work this out in Arc10.
From my experience (also not a remote sensing expert), it's very hard to get accurate building outlines. If it is not a huge area, it might be worth manually tracing the buildings and then doing a spatial join with the LIDAR data to get the building heights.
My suggestion would be to create two rasters, one from the first returns to create a Digital Surface Model (DSM). Then create a "bare earth" DEM using the last returns. Next, create a normalized DSM (nDSM) by subtracting the DEM from the DSM which will give relative heights above an assumed baseline of "0". From there, you can extract the values of the raster to the building polygons (provided you have the footprints) using either the mean value or max or whatever you choose.
Is it possible to turn the entire lidar model into a single surface, then grab faces that are vertical or near-vertical? I would think they'd represent buildings - but I don't know ArcGIS well enough to know if this is possible.
