generating distance map for Large map
On Monday 21 July 2008, milton ruser wrote:
Dear all, I have a very large BINARY image (60,000x50,000 pixels) and need to generate the distance map from the 1 values. When the images are small than my image, I can generate the distance map using ArcGis (my image is in .IMG format), but ArcGis return error for this large one. I am running R 2.7.1 under windows/xp. Is there a way of do this job using R ou RSaga? (unfortunately I don?t have GRASS installed), and my experience with RSAGA is near zero. My computer is 4GB ram. I can load the images on ArcGis and Erdas without problem, but I only don?t know how do this task.
Try and use GRASS. It is made for these types of operations. Since R is memory-bound (for most practical purposes) a sequential-access approach like GRASS should work much better. There is a windows installer for GRASS, or you can just install the latest QGIS: this comes with GRASS! Cheers, Dylan
Dylan Beaudette Soil Resource Laboratory http://casoilresource.lawr.ucdavis.edu/ University of California at Davis 530.754.7341