Hi Folks, Just though I'd let people know that there is an experimental branch ("THK") of rgdal in CVS at the sourceforge site. It passes "R CMD check" on my machine.
Major changes are: 1) "new" is no longer used to open datasets. "openDataset" (or equivalently "GDAL.open") is now the only way to open existing datasets, eg, ds1 <- openDataset("test.tif", read.only = FALSE) I'd like to have a consistent set of function names, so I'm considering deprecating GDAL.(open|close). 2) A "createDataset" function is defined to make it easy to create a GDAL dataset to hold the output of your analysis, eg, ds2 <- createDataset("GTiff", 1024, 1024, 1, "Float64", "output.tif") # calls to putRasterData closeDataset(ds2) (Also, in general you can now provide either the driver object or the driver name as a string.) 2a) There are some tricky issues with the "copyDataset" (GDAL's copy dataset function does not actually copy any data by design) and "saveDataset" functions. These may go away or be rewritten from scratch. 3) The "offset" argument to "getRasterData" and "getRasterTable" has been replaced with "at" which specifies the location of the upper-left corner to begin reading/writing rather than the offset from the image origin. This simplifies looping over scanlines or blocks. I'd like to see this change however to some more general and flexible mechanism of specifying data regions. One that would allow using (x,y) and (row,column) interchangably, and perhaps in the future allow for arbitrary polygons. 4) A new function "RGB2PCT" will convert three bands of raster data into a single-band dithered image with a pseudocolor lookup table. The "displayDataset" function has returned. It only displays a single band, but will automatically use the pseudocolor lookup table generated by "RGB2PCT" (or whatever color table is attached to the raster band). "displayDataset" automatically decimates the input to make drawing the image faster, but does not yet use embedded overviews. (Roger also has a function that takes a 3-band SpatialGridDataFrame and dithers/builds the PCT -- we probably need to merge these or wrap one with the other.) The change from "offset" to "at" is likely to have broken the "sp" related functions. We'll need to review those or come up with the alternative to "at" and rewrite as necessary. A few more items that would be nice to include might be having "getRasterData" and "putRasterData" return/accept "sp" objects. It will add an extra step when reading raster data as it would require the data to be unpacked from the "sp" object for manipulation in R (if I understand the "sp" setup). It would be no more than obj$data or something like that. Cheers, Tim -- Timothy H. Keitt http://www.keittlab.org/ _______________________________________________ R-sig-Geo mailing list R-sig-Geo@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo