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Unread 19 June 17, 19:48   #60
Join Date: Apr 2008
Location: Fiat Farm, in the wettest corner of Oregon
Age: 55

The fields to change in NOAA Digital Coast when you're checking out:

Better to use LAZ rather than LAS at this point to save download bandwidth, which I forgot to do in this example.

What a top view of the data looks like in CloudCompare after switching to intensity, setting blue-green-red-yellow as color, and shortening range to match actual values:

Filtering the data for only classification 2 (ground return) eliminates trees, water, etc:

There are still some 20 million points in the cloud. Trimming away most of the non-road area, leaving a buffer of about 100 meters, will get you down to 1 million points.

Exporting that to a CSV file and opening it in a spreadsheet will look like:

You only need the X, Y, Z, & intensity columns for the BTB import. See how big the numbers for X & Y are? They're outside the range that BTB can handle which is why you need to translate them to a local (0,0,0) reference. Even the Z values should be brought down so the lowest point is zero (or within 5 meters). You'll also need to switch the Y & Z columns before importing. Finally, BTB can only reliably import about 250k points at a time, so a million point file needs to be broken into 4 separate files.

Last edited by Emery; 19 June 17 at 20:09.
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