The rimage package has functions for reading in and plotting jpeg files that you could use for displaying the photograph. If you then can find 2 points in the image (not on the same horizontal or vertical line) for which you know the coordinates in the coordinate system that you want to plot in, then you can use the updateusr function from the TeachingDemos package to set the user coordinates, then use points/lines or other functions that can add to the current plot (e.g. contour with add=TRUE) to overlay the information of interest to the plot.
Also look at the squishplot function in TeachingDemos for one way to set the aspect ratio of the original image. Hope this helps, ________________________________________ From: [EMAIL PROTECTED] [EMAIL PROTECTED] On Behalf Of Waichler, Scott R [EMAIL PROTECTED] Sent: Monday, October 13, 2008 3:02 PM To: [EMAIL PROTECTED] Subject: [R] Using an image background with graphics I would like to use a map or aerial photo as a background to plotting solid lines and text, and semi-transparent color contours, in base and lattice graphics. Plot coordinates need to be consistent with the georeferenced background. For example, a color contour plot would have an gray-toned aerial photograph as a background for overprinted semi-transparent color contours of some spatially dependent variable. Can anyone point me in the right direction on how to do this? Thanks, Scott Waichler Pacific Northwest National Laboratory [EMAIL PROTECTED] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
