Greetings Spatial R users/developers, I was curious as to whether or not it would be possible to describe a bounding box for a large image so that what is read into R would be just the contents of the image inside the bounding box. Conceptually, it would be akin to "clipping" the image but without the image read into the program. My issue is that I have a very large 3-band orthophoto of several hundreds of hectares of forest (roughly 8MB image). I am running an analysis of LIDAR data that requires the user to select a smaller area of a highly degraded lidar image. I would like the bounding box of this LIDAR area to be used to "clip" a georegistered orthophoto that complements the LIDAR data. However, the complete ortho image seems to crash my WindowsXP, R v2.4.1 setup. When I take the bounding box coordinates into ERDAS Imagine and subset the orthophoto the following code works fine to bring it into R:
## Read in Tif file setwd(anypathway) tif.image <- "Pre_Subset_Image.tif" LIDAR.tif <- GDAL.open(tif.image) dim(LIDAR.tif) image(LIDAR.tif[,,1]) ## This converts the rgdal class to an SpatialGridDataFrame class LIDAR.tif.1 <- LIDAR.tif[,] bbox(LIDAR.tif.1) image(LIDAR.tif.1,main="") mtext("Orthophoto of Preloaded Fusion Example", side=3, line = 3, font=3, cex=1.25) However, this would be impractical with the code that I am building to jump out of R and subset images in Imagine (plus very expensive for the end user). Therefore, does anyone have any solutions for reading in an image that would work in theory like the following: setwd(anypathway) tif.image <- "VERY_LARGE_IMAGE.tif" Bounded.tif <- GDAL.open(tif.image, bbox=c(UpL.X, LwR.X, UpL.Y, LwR.Y)) By the way, I am not set on GDAL.open as the solution but it seems to work well reading in Tifs & Jpegs. Again, thanks in advance Andrew Niccolai Doctoral Candidate Yale School of Forestry _______________________________________________ R-sig-Geo mailing list R-sig-Geo@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo