Changes between Version 1 and Version 2 of Processing/LIDARDEMs

Timestamp:

Apr 8, 2008, 6:37:52 PM (17 years ago)

Author:

benj

Comment:

--

Processing/LIDARDEMs

@@ -43 +43 @@
 }}}
 
-In the given example, there are a very few values between 20-30m at the bottom end, and a big gap at the top end before a small number of values above 590m (nothing between 240m and 590m). So it would be sensible to pick 30m as a minimum cutoff and 250m as a maximum.
+In the given example, there are a very few values between 20-30m at the bottom end, and a big gap at the top end before a small number of values above 590m (nothing between 240m and 590m). So it would be sensible to pick 30m as a minimum cutoff and 250m as a maximum. Note that because the histogram is on a log scale the difference in numbers of points at both ends is much larger than it looks at first glance.
 
 3. Open GRASS, select (or create) an appropriate UTM/WGS84 location and set the region appropriately for the dataset - easiest way is to look at the start of the trimmed lidar data file for the starting co-ordinates of the first line, set an approximate region from there, view the map in GRASS and then adjust the region appropriately.