Changes between Version 1 and Version 2 of Processing/LIDARDEMs


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Timestamp:
Apr 8, 2008 6:37:52 PM (12 years ago)
Author:
benj
Comment:

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  • Processing/LIDARDEMs

    v1 v2  
    4343}}}
    4444
    45 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.
     45In 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.
    4646
    47473. 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.