Your example or description is not perfectly clear to me so I may be off, but wouldn't you be better off by reading your files into a RasterBrick or RasterStack, summing through the layers and multiplying by a ratio?
Cheers, Roman On Wed, Oct 10, 2012 at 4:29 PM, Milena <[email protected]> wrote: > Hello! > I hope someone can help me! I have radar images, they're matrixes 240x240 > in TXT format. The information is about rain, in mm/h. I need to transform > them to total rain (only mm), so I have to multiply the matrixes to 5/60 > (temporal resolution is 5 minutes). > Well, I have a script that theorically can make this ratio. It makes a > looping too because I have too many images. But, it's not working... > Any ideia about what is going wrong? Or another way to make this > multiplication? > Thanks!!!! > Milena Fogliarini Brolesi > (Unicamp) > > #create the raster based in another raster image (cappi_dimension)and set > value = 0 to make the sum possible > > cappi_example<-raster(readAsciiGrid("C:/Users/MFB/Documents/Mestrado/cappi_teste/V1_CAPPIH030R2_20030101_1534.txt", > as.image = FALSE, proj4string = CRS("+proj=longlat +datum=WGS84"))) > cappi_example[is.na(cappi_example)]<-0 > cappi_raster_sum<-setValues(raster(cappi_example, filename = > "cappi_raster_sum", values = NULL), values = 0) > > #for loop to read all images in a folder, sum all images and aply a ratio > to transform mm/h in mm > ratio<-5/60 > > for (ii in 1: length(file_list)) { > > file_path<-paste(folder_path, file_list [ii],sep = "") > library(raster) > cappi<-raster(readAsciiGrid(file_path, as.image = FALSE, proj4string = > CRS("+proj=longlat +datum=WGS84"))) > cappi[is.na(cappi)]<-0 > cappi_raster_sum<-sum(cappi_raster_sum,cappi)*ratio > } > summary(cappi_raster_sum) > > [[alternative HTML version deleted]] > > _______________________________________________ > R-sig-Geo mailing list > [email protected] > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > -- In God we trust, all others bring data. [[alternative HTML version deleted]] _______________________________________________ R-sig-Geo mailing list [email protected] https://stat.ethz.ch/mailman/listinfo/r-sig-geo
