windowed reading raster with stars

See https://github.com/r-spatial/stars/issues/276

should be fixed now.

Thanks!

On 4/25/20 6:06 PM, Lo?c Dutrieux wrote:

Hi Edzer,

Below an example that generates a raster with the exact same dimensions
and reproduces the "error". I did not manage to set raster values when
creating the artificial data though; it's too large to handle in memory.

library(stars)
library(sf)
library(raster)

file_path <- tempfile(pattern = "raster", fileext = ".tif")
e <- new("Extent", xmin = 15.470217297, xmax = 15.489599681, ymin =
1.097371925, ymax = 1.111615391)
b <- brick(e, nrows=20349, ncols=27872, nl=3, crs=CRS('+proj=longlat'))

writeRaster(b, filename = file_path, datatype='INT1U')

window <- read_stars(file_path, proxy = TRUE) %>%
 ??? st_bbox() %>%
 ??? st_as_sfc() %>%
 ??? st_buffer(-0.001) %>%
 ??? st_bbox()

tif_sub <- read_stars(file_path, proxy = TRUE) %>%
 ??? st_crop(window)
plot(tif_sub)

Kind regards,
Lo?c

On 04/25/2020 05:27 PM, Edzer Pebesma wrote:

Hi Lo?c,

could you please make an example available somehow, possibly off-list?

On 4/25/20 5:14 PM, Lo?c Dutrieux wrote:

Hi everyone,

I have a large geoTiff raster file that does not fit in memory (if I do
read_stars(file_path) I get "Error: cannot allocate vector of size 12.7
Gb"). How can I read a spatial subset of that file.

The example below works with a toy example but not with the actual large
dataset.

library(stars)
library(sf)

tif = system.file("tif/L7_ETMs.tif", package = "stars")
window <- read_stars(tif) %>%
 ???? st_bbox() %>%
 ???? st_as_sfc() %>%
 ???? st_buffer(-2000) %>%
 ???? st_bbox()

tif_sub <- read_stars(tif, proxy = TRUE) %>%
 ???? st_crop(window)

plot(tif_sub)

I get the following error:

Error in x[[i]][1:-21561856, 1:146, , drop = FALSE] :
 ?? only 0's may be mixed with negative subscripts

Kind regards,
Lo?c