The volume of a polygon = 0. Polyhedra have volumes. This may be irrelevant, but if the lake is cylindrical == constant cross sectional area at all depths, then height doubles when the volume does and vice versa. Otherwise you have to know how area varies with height or use more sensible approximations thereto.
Cheers, Bert On Tue, Dec 5, 2023, 20:13 javad bayat <j.bayat...@gmail.com> wrote: > Dear all; > I am trying to calculate the volume of a polygon shapefile according to a > DEM raster. I have provided some codes at the end of this email.I dont know > if the codes are correct or not. Following this, I have another question > too. > I want to know if the volume of the reservoir rises or doubles, what would > be the elevation? > I would be more than happy if anyone could help me. > Sincerely > > " > library(raster) > library(terra) > library(exactextractr) > library(dplyr) > library(sf) > r <- raster("Base.tif") > p <- shapefile("p.shp") > r <- crop(r, p) > r <- mask(r, p) > x <- exact_extract(r, p, coverage_area = TRUE) > > x1 = as.data.frame(x[1]) > head(x1) > x1 = na.omit(x1) > > x1$Height = max(x1[,1]) - x1[,1] > > x1$Vol = x1[,2] * x1[,3] > > sum(x1$Vol) > > " > > -- > Best Regards > Javad Bayat > M.Sc. Environment Engineering > Alternative Mail: bayat...@yahoo.com > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.