On Fri, 27 Oct 2006, Duncan Golicher wrote: > I have quite a number of SpatialGridDataFrame objects that were saved > internally under R 2.3.0 and sp0.8-16. Can anyone suggest a quick and > easy way to convert them for use with R2.4.0 and sp0.9-2. (I do have > ways, but they are all a bit longwinded).
The issue was announced on this list on 28 September: https://stat.ethz.ch/pipermail/r-sig-geo/2006-September/001354.html and has been on the Rgeo site since about the same time. The major issue is that the way new-style classes (and objects belonging to those classes) are defined internally, so the internal (*.RData) representations are not compatible. To transfer from the old internal form, use R < 2.4.0, and sp < 0.9 to for example export column by column to GRASS, and then read back in in R >= 2.4.0 and sp >= 0.9. Alternatively for non-GRASS users, rgdal and the GTiff fotmat could be used (and should work with multiple bands). The writeAsciiGrid() function in maptools could also be used. There is no way of upgrading the serialised object from the *.RData form directly. We know that this is an unfortunate incompatibility, but the changes in the methods package are being made to improve class/object handling, making the software faster and more robust, so the difficulties are unavoidable. For critical projects already using R < 2.4.0, I suggest only upgrading when sensible. Roger > > Thanks, > > Duncan > > -- Roger Bivand Economic Geography Section, Department of Economics, Norwegian School of Economics and Business Administration, Helleveien 30, N-5045 Bergen, Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43 e-mail: [EMAIL PROTECTED] _______________________________________________ R-sig-Geo mailing list R-sig-Geo@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo