Yong, I would have loved to see your R shaking.
This argument has been heard more often here. When processing massive
grids, please have a look at the function getRasterData in package
rgdal. It allows you to _read_ only portions of a grid.
--
Edzer
Yong Li wrote:
Thanks Edzer and Hengl. It works.
But R is really shaking when large grids are processed. We wish there
is improvement of sp in the future like GIS handling grids.
Regards
Yong
------------------------------------------------------------------------
*From:* Edzer Pebesma [mailto:[EMAIL PROTECTED]
*Sent:* Tue 20/05/2008 6:11 PM
*To:* Yong Li
*Cc:* r-sig-geo@stat.math.ethz.ch
*Subject:* Re: [R-sig-Geo] How to subset a spatial grid?
Have you tried
Map1 <- Map[1:100,1:100]
?
Note that this works differently for SpatialGridDataFrames and
SpatialPixelsDataFrames; the first knows about [rows,cols,bands], the
second about [pixels, bands].
--
Edzer
Yong Li wrote:
> Dear All,
>
> I want to subset a large spatial grid (2000*2000) into many smaller
> grids for further processing in my simulation models. Could anyone do it
> before and any tips will be highly appreciated?
>
> Library(rgdal)
> Map <- readGDAL("yong.img") # one image from erdras imagine
> Map$va <- Map$band1
> Map$band1 <- NULL
> ????
> Map1 <- a subset of Map$va based on selected cols and rows.
> ????......
>
> Cheers
>
> Yong Li
>
> _______________________________________________
> R-sig-Geo mailing list
> R-sig-Geo@stat.math.ethz.ch
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>
_______________________________________________
R-sig-Geo mailing list
R-sig-Geo@stat.math.ethz.ch
https://stat.ethz.ch/mailman/listinfo/r-sig-geo
