Dear All,

I am using the "extract" command to extract the fraction of each class in
the raster cells, falling in each grid of shape file of polygon type.
> extract(r,v) ### where 'v' is my polygon grid of 1 km resolution and 'r'
is my classified raster image.

My polygon grid has more than 2 million polygons and I am running the
command in 64 bit window xp operating system having quard 4 processor and 8
GB RAM. But the extract function is taking a long time (more than 2 days) to
generate results.
please help me how can I speed up the processing time. Is there any other
packages in R that can provide the fast processing for this type of
extraction.

Also, how can I read one polygon at a time in R from the polygon shape file
stored in disk.

Thanks in advance for the valuable suggestions.

With regards
Rahul Raj
Indian Institute of Remote Sensing, india.

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