From giulia.cerritelli at biologia.unipi.it Tue Apr 20 10:20:14 2021 From: giulia.cerritelli at biologia.unipi.it (g.cerritelli) Date: Tue, 20 Apr 2021 10:20:14 +0200 Subject: [tlocoh-info] problem in converting isopleths to rasters Message-ID: <4a72aed3ee2c8ee5c6c99332fc9ad822@biologia.unipi.it> Hi all, I have a question on converting isopleths to rasters using the function lhs.iso.rast. My final goal is to evaluate the percentage of overlap between animals home range for which I would like to use the function kerneloverlap in adehabitatHR. To this aim I need to convert the isopleths of all animals using the same raster for all animals as grid. I have tried to use the function lhs.iso.rast setting in the function arguments a raster layer as grid, but I get an error I don't know how to solve. I would really appreciate if anyone can give me some suggestions on how to solve the problem. Here I have reported an example: ##Create the locoh-xy and select one ID utm.lxy <- xyt.lxy(xy = coordinates(data.utm), dt=NULL, id= data.utm$ID, proj4string=CRS("+proj=utm +zone=32 +ellps=intl +units=m +no_defs")) lxy_89 <- lxy.subset(utm.lxy, id = "3") ##I use the a-method and select the best values (I have not reported here all the selection procedures) and then I finally obtain the lhs object 89.lhs.a <- lhs.select(89.lhs.amixed, a=160000) ##I create a SpatialPixel that I then transform to raster > x <- seq(519000, 791000, by=500) # resolution is the pixel size you > desire (500 m) > y <- seq(4500000, 4900000, by=500) > xy <- expand.grid(x=x,y=y) > coordinates(xy) <- ~x+y > gridded(xy) <- TRUE > class(xy) [1] "SpatialPixels" attr(,"package") [1] "sp" > r <- raster(xy) > proj4string(r) = proj4string(data.utm) > r class : RasterLayer dimensions : 801, 545, 436545 (nrow, ncol, ncell) resolution : 500, 500 (x, y) extent : 518750, 791250, 4499750, 4900250 (xmin, xmax, ymin, ymax) crs : +proj=utm +zone=32 +ellps=intl +units=m +no_defs ##I try to convert the isopleths to raster, and here I get the error > SCOLA_89.lhs.a <- lhs.iso.rast(SCOLA_89.lhs.a, raster = r, status=TRUE) Converting isopleths to rasters 3.pts812.a160000.s0.kmin0 Error in round(nrows) : non-numeric argument to mathematical function ##Note: If I use just the cell size as argument, the function correctly transforms the isopleths, thus I don't think it is a problem in the lhs object > SCOLA_89.lhs.a <- lhs.iso.rast(SCOLA_89.lhs.a, cell.size=100, > status=TRUE) Converting isopleths to rasters 3.pts812.a160000.s0.kmin0 |=================================================================================| 100% Total time: 3.4 secs Thank you in advance for any help you can provide Best, Giulia