On 16/09/2010 11:02, Julio Cesar Canales DElgadillo wrote:
Very large layers? Enough memory in the computer? For clipping, two ways come to mind. The GDAL utility ogr2ogr has an option -clipsrc. Here you specify the xmin, ymin, xmax and ymax bounding box. So something like: ogr2ogr -clipsrc 200000 500000 210000 510000 original.shp clipped.shp Alternatively, if you create a polygon shapefile identical to your new extent, then in QGIS select Vector->Geoprocessing Tools->Clip. This will "cookie cut" your original with the extent polygon. Converting to raster is a different issue altogether. If you want to interpolate between vector features, then you have to choose the interpolation method and parameters. If you simply want raster cells to have some value from the shape features, and NULL everywhere else, then you can use the v.to.rast modules from the GRASS plugin. HTH
-- Micha Silver http://www.surfaces.co.il/ Arava Development Co. +972-52-3665918 |
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