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Cropping DEM
Posted: 27 Apr 2011 10:51
by nicknackpaddywack
Hi, for some reason I cannot seem to crop. I have a large DEM Map and only want a small portion, i've tried looking through the help but I cannot work out how to reduce the size of the DEM.
Re: Cropping DEM
Posted: 27 Apr 2011 11:17
by geophil
The scissors tool is used for cropping. Create either a rectangular mask or - new for cropping in TransDEM 2.1.3 - a bounded region of DEM control points. Select the scissors tool, click outside the mask or bounded region, confirm "outside" and let TransDEM process the DEM. Save your cropped DEM with a new name afterwards.
See also TransDEM main manual page 24 "Erasing DEM Points" (intro) and page 68 "Menu Item: Erase DEM Points".
Re: Cropping DEM
Posted: 27 Apr 2011 12:57
by nicknackpaddywack
The problem im having is removing the black area around the DEM as shown below:
Re: Cropping DEM
Posted: 27 Apr 2011 13:12
by geophil
nicknackpaddywack wrote:The problem im having is removing the black area around the DEM
That will be always done automatically once you save the cropped DEM to file.
You can also explicitly apply the "Crop DEM margins" function but this will not have a visual affect if raster maps are loaded on top of the DEM.
[Edit and off-topic]:
BTW, have a look at
UK Ordnance Survey Land-Form Panorama 50m DEMs, as a replacement for SRTM 3 arc sec