Hello, I haven't downloaded the data, but a mock-up of your steps below does as you ask. You can see the resolution of y is 1 x 1 and each is filled with the sum of 120 x 120 original cells each of which had a value of 1.
In this case, the raster package faithfully interprets the fractional degree spatial units from the get-go. So you needn't worry about the arc-second to degree issue. Ben P.S. This question is about spatial data; your best results will be had by subscribing to and posting to the spatial mailing list for R. https://stat.ethz.ch/mailman/listinfo/r-sig-geo library(raster) x <- raster( nrows = 17400, ncols = 43200, xmn = -180, xmx = 180, ymn = -60, ymx = 85, crs = '+proj=longlat +datum=WGS84 +no_defs +ellps=WGS84 +towgs84=0,0,0') x[] <- 1 x class : RasterLayer dimensions : 17400, 43200, 751680000 (nrow, ncol, ncell) resolution : 0.008333333, 0.008333333 (x, y) extent : -180, 180, -60, 85 (xmin, xmax, ymin, ymax) coord. ref. : +proj=longlat +datum=WGS84 +no_defs +ellps=WGS84 +towgs84=0,0,0 data source : in memory names : layer values : 1, 1 (min, max) y <- aggregate(x, fact = 120, fun = sum) y class : RasterLayer dimensions : 145, 360, 52200 (nrow, ncol, ncell) resolution : 1, 1 (x, y) extent : -180, 180, -60, 85 (xmin, xmax, ymin, ymax) coord. ref. : +proj=longlat +datum=WGS84 +no_defs +ellps=WGS84 +towgs84=0,0,0 data source : /private/var/folders/xx/nnm6q33102z059rfg4rh2y900000gn/T/RtmpgsByoE/raster/r_tmp_2016-11-29_180022_89972_05480.grd names : layer values : 14400, 14400 (min, max) > On Nov 29, 2016, at 5:45 PM, Miluji Sb <miluj...@gmail.com> wrote: > > Dear all, > > I am using the Gridded Population of the World (v4) for the year 2010. The > data is in GeoTiFF format. > > Source: > http://sedac.ciesin.columbia.edu/data/set/gpw-v4-population-count-adjusted-to-2015-unwpp-country-totals/data-download > > I imported the data using: > > library(raster) > library(maptools) > library(ncdf4) > library(rgdal) > > population <- > raster("gpw-v4-population-count-adjusted-to-2015-unwpp-country-totals_2010.tif") > population1 <- stack(population ) > extent(population1 ) <- c(-180, 180,-58,85) > > ### Information > class : RasterStack > dimensions : 17400, 43200, 751680000, 1 (nrow, ncol, ncell, nlayers) > resolution : 0.008333333, 0.008333333 (x, y) > extent : -180, 180, -60, 85 (xmin, xmax, ymin, ymax) > coord. ref. : +proj=longlat +datum=WGS84 +no_defs +ellps=WGS84 > +towgs84=0,0,0 > names : > gpw.v4.population.count.adjusted.to.2015.unwpp.country.totals_2010 > min values : > 0 > max values : > 141715.3 > ### > > I need to extract population by a set of coordinates which are at 1° x 1°, > how can I convert from arc-second to degree in R? The information also > shows that resolution is 0.008333333° x 0.008333333°, is it enough to do > something like this? > > pop_agg <- aggregate(population1 , fact=120, fun=sum) > > Thank you very much. > > Sincerely, > > Milu > > [[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. Ben Tupper Bigelow Laboratory for Ocean Sciences 60 Bigelow Drive, P.O. Box 380 East Boothbay, Maine 04544 http://www.bigelow.org ______________________________________________ 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.
