Re: [R-sig-Geo] stars analogous of raster::aggregate

[Micha Silver]

On 08/09/2020 19:33, Julian M. Burgos wrote: Dear all, The raster package has the raster::aggregate function that can be used to reduce the resolution of a raster by aggregating cells by a specific factor. For example, this reduces the resolution of the L7_ETMs.tif raster by a factor of 10: library(raster) rst1 <- raster(system.file("tif/L7_ETMs.tif", package = "stars")) rst2 <- aggregate(rst1, fact = 10, fun = mean) res(rst1) [1] 28.5 28.5 res(rst2) [1] 285 285 I am trying to do the same thing with a stars object. The stars package has the stars::aggregate function, but for spatial aggregation it takes an object of class sf or sfc, so it is meant to be used for aggregation over polygons. I could do something like this: Probably st_warp() is what you want: l7_file = system.file("tif/L7_ETMs.tif", package = "stars") l7 = read_stars(l7_file) l7_lowres = st_warp(src = "" cellsize = c(90, 90), crs = st_crs(l7)) stars::st_dimensions(l7)      from  to  offset delta                       refsys point values    x       1 349  288776  28.5 +proj=utm +zone=25 +south... FALSE   NULL [x] y       1 352 9120761 -28.5 +proj=utm +zone=25 +south... FALSE   NULL [y] band    1   6      NA    NA                           NA    NA   NULL    stars::st_dimensions(l7_lowres)      from  to  offset delta                       refsys point values    x       1 111  288776    90 +proj=utm +zone=25 +south...    NA   NULL [x] y       1 112 9120761   -90 +proj=utm +zone=25 +south...    NA   NULL [y] band    1   6      NA    NA                           NA    NA   NULL   -- Micha Silver Ben Gurion Univ. Sde Boker, Remote Sensing Lab cell: +972-523-665918 https://orcid.org/0000-0002-1128-1325

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