As it turns out, ImageMagick runs into problems with these images before the GIMP does. ImageMagick ALWAYS reserves 5 bytes per pixel when working with a Q8 image (even if grayscale), and runs into the 2GB file size limit with 400MB images as a result. The GIMP does not have this problem when dealing with grayscale images, because it doesn't reserve 5 bytes per pixel like ImageMagick does. Unfortunately, the GIMP still runs into some other kind of problem when the physical length of any one dimension of the image exceeds about 187.5 feet, but this is NOT a file size or pixel count limit. I can trick the GIMP into working with an image that it would otherwise have problems with by merely increasing the dpi in the metadata for the file, thereby fooling the GIMP into thinking that the physical dimensions of the image are smaller than they really are. Another reason for using the GIMP is that I must also be able to DISPLAY these images and work with them to some degree interactively. ImageMagick can't handle these requirements. It should be noted that there ARE other programs available that can work with images of this size with no difficulty at all, even on systems with relatively little RAM. They do this by NOT attempting to load the whole image into memory at once, but instead only working with smaller chunks at once. However, all of the programs that I am aware of in this category have one of two problems where my use is concerned: 1) they are either prohibitively expensive, or 2) they don't have the capabilities that I need. Right now, the GIMP, despite it's imperfections, is the closest thing that I have found to meeting my needs, so far... If I could just get this one bug fixed, then the GIMP could do most everything that I need. In the meantime, I've developed a separate tool to help me work around the problem by changing the dpi values without resampling or changing the total pixel count. s/KAM ----- Original Message ----- From: "Steinar H. Gunderson" <sgunderson@xxxxxxxxxxx> To: "gimp developers" <gimp-developer@xxxxxxxxxxxxxxxxxxxxxx> Sent: Friday, January 10, 2003 5:17 AM Subject: Re: [Gimp-developer] GIMP Image Size Limits > On Fri, Jan 10, 2003 at 05:13:31AM -0600, Kevin Myers wrote: > > Yes, some of these images exceed 200ft in length. You may be wondering what > > they could be: images of well logs for oil and gas wells. These are > > essentially strip chart (graphical) recordings of various physical > > properties taken over the length of the borehole. > > Are you sure you want to use GIMP to work with this sort of things anyhow? > What really do you want to do to them -- are you sure ImageMagick wouldn't be > a better choice for most operations? > > /* Steinar */ > -- > Homepage: http://www.sesse.net/ > _______________________________________________ > Gimp-developer mailing list > Gimp-developer@xxxxxxxxxxxxxxxxxxxxxx > http://lists.xcf.berkeley.edu/mailman/listinfo/gimp-developer
