I downloaded GTOPO30
*.DEM files, and extracted a contour line at 2000m altitude using
gdal_contour. In the resulting shapefile, I have many small polygons in areas where the altitude is close to that contour line, and the image looks quite noisy.
How can I, preferably using gdal/ogr or QGis, somehow 'downsample' these contours, so that the picture looks cleaner? I basically want to eliminate all small features.
PS: One way would be to downsample the grid before doing the contour extraction; is this the way to go, or should i rather downsample the shapefile?