Hi Matt (and list), ArcGIS still (as far as I know) doesn't work with rectangular cells. This isn't a problem with the AsciitoGrid function, but I think is more fundamentally a problem with Arc's raster data structure.
The trick to getting around this may be to convert your matrix to a point object - with x, y, and z values - in R, where x and y correspond to the ground coordinates of each cell in the matrix. I think you would have to do this with your own code, but if you've programmed with arrays before it would not be difficult. Then interpolate these points to a square grid. The interpolation could be done in R (using gstat routines for example) or within a GIS (that is, write the xyz object to a text file, or perhaps straight to a shapefile, import it as a vector point set to a GIS, and then convert that to a raster. Hope this helps, Ashton On Tuesday 29 July 2008, [EMAIL PROTECTED] wrote: > Dear list, > > I'm trying to bring an ASCII raster file into ArcGIS that resulted from > calling the R function Tsp(), which is in the "fields" library, followed > by the use of the function predict.surface() to generate the matrix of > predicted values. These functions use many of the same inputs as the > Krig() function in R. My problem is that the output is a symmetrical > matrix of dimension NxN, however, because R outputs an NxN matrix it > necessarily results in having a rectangular grid cell (e.g., x dimension > is 50 and y dimension is 30) for any input data set whose spatial extent > is not square. > > My question is; does anybody know how to import a rectangular grid from an > ASCII raster file into ArcGIS using something other than the AsciiToGrid > function in ArcGIS, which only allows for square grids? > > Thanks in advance for any help, > Matt > > ************************************************* > Matt Farnsworth > Disease Ecologist > Spatial Epidemiology Unit > Centers for Epidemiology and Animal Health -- Ashton Shortridge Associate Professor [EMAIL PROTECTED] Dept of Geography http://www.msu.edu/~ashton 235 Geography Building ph (517) 432-3561 Michigan State University fx (517) 432-1671 _______________________________________________ R-sig-Geo mailing list R-sig-Geo@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo