Hello,
I have four doubts: 1) why gzAzymuth is giving me Northern direction in this case, for example? require(sp); require(rgdal) kk=data.frame(x=c(575552.8,576295.9), y=c(4103900,4103611)) coordinates(kk)=~x+y plot(kk, typ="o", col=4) gzAzimuth(coordinates(kk)[1,], coordinates(kk)[2,]) 2) how to cut a polygon (for example a border file) into chuncks? (i.e. separate areas, according to a line) 3) how to create multiple polygons, from a grid file, according to a criteria. For example, : require(gstat) data(meuse) coordinates(meuse) = ~x+y data(meuse.grid) gridded(meuse.grid) = ~x+y m <- vgm(.59, "Sph", 874, .04) # ordinary kriging: x <- krige(log(zinc)~1, meuse, meuse.grid, model = m) spplot(x["var1.pred"], main = "ordinary kriging predictions") # how to create a polygon with the areas greater than 5... 4) Is it defined in proj4, the datum lisboa, Sistema of Hayford- Gauss Militar? and UTM, using zone 29N (29 is down here, for example...)? CRS("+proj=utm +zone=29 +datum=WGS84") How do we specify it? Thank you very much in advance,... any help will be much appreciated... Best regards, Marta [[alternative HTML version deleted]] _______________________________________________ R-sig-Geo mailing list R-sig-Geo@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo