I have 42 jpg files with corresponding jgw world files totaling 65MB to import into GRASS at any given time. I'm using r.in.gdal to import this data, which takes about 6 minutes and splits each of these files into their RGB components. Then I merge the raster data with r.patch input=image0.red,image1.red,...,image42.red output=map.red and so on for green and blue. When all is said and done, the image size is roughly 15000 x 13000 pixels. Then I create a composite image with r.composite and output the whole thing to a PNG or TIFF file using r.out.png or r.out.tiff. I'm not sure how fast r.composite will run because r.patch is still only 70% of the way through green, and I've been running this for the past 45 minutes. Does anyone know of a faster way to merge these images together? As it stands, this will run for more than an hour for only 65MB of data. This is way too slow for our purposes and for most people's sanity. I read that GRASS stores its raster data compressed and that compressed data may execute faster when the disk would otherwise be accessed a lot, but would it run faster if the images were uncompressed with r.compress -u? I've searched around some, and I haven't found any commands that might be faster, but if anyone has any suggestions on how to speed up this process, I'd be happy to hear them.
Thanks,
David