Cropping DEM

[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.

[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".

[nicknackpaddywack]

The problem im having is removing the black area around the DEM as shown below:

[geophil]

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