The "seek" command will allow you to skip to a particular byte position in the file. You can define the position you want relative to your current position, or to the start of the file. Hope this helps, Matt Wiener -----Original Message----- From: r-help-bounces at stat.math.ethz.ch [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Jonathan Greenberg Sent: Thursday, February 12, 2004 9:51 PM To: R-help Subject: [R] Readbin and file position I have a binary file which is an image with multiple bands, arranged in BSQ format such that R, B and G are all N x M sized matrices (corresponding to Red, Blue and Green colors respectively). The BSQ file arranges the data as [R, B, G], so to access the B matrix, I have to read forward N x M + 1 number of samples. Is there a fast way to define a variable as the B matrix exclusively (e.g. Can I use readbin to "fast forward" N x M + 1 samples to the beginning of the B matrix, and then read/define the B matrix exclusively, or do I have to read the entire file into memory, then subset out the B matrix?) Thanks! --j
Jonathan Greenberg Graduate Group in Ecology, U.C. Davis http://www.cstars.ucdavis.edu/~jongreen http://www.cstars.ucdavis.edu AIM: jgrn307 or jgrn3007 MSN: jgrn307 at msn.com or jgrn3007 at msn.com ______________________________________________ R-help at stat.math.ethz.ch mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html ------------------------------------------------------------------------------ Notice: This e-mail message, together with any attachments,...{{dropped}}