[R] extract function extracting only NA values

[Fabio Berzaghi]

Hello,

I have five raster files in ASCII format. With four of them I have no 
problem extracting values based on a set of X and Y coordinates. 
Unfortunately with one of the files all I managed to extract is NA 
values. To verify the problem I have opened the raster with ArcMap and 
there are no NA values where I am extracting. I have also plotted the 
spatial point class on top of the raster in R and it does correspond to 
the correct locations.

These are some of the commands I am using, and as I already pointed out 
that works perfectly with other raster files.

sp<-SpatialPoints(xysp)
xy$rasterimg<-extract(rasterimg,sp)

Can anyone help? At this point I am rather clueless about this.

Thanks