Digging into the code for raster::compareRaster():
library(raster)
r <- raster(ncol=3, nrow=3)
values(r) <- 1:ncell(r)
r2 <- r
values(r2) <- c(1:8,10)
all.equal(getValues(r), getValues(r2), tolerance = 0)
[1] "Mean relative difference: 0.1111111"
compareRaster has fancier machinery internally for doing the
comparison for large rasters a block at a time if everything can't fit
in memory at the same time ...
On 2024-08-15 9:14 a.m., SIBYLLE STÖCKLI via R-help wrote:
Dear community
Similar to the example of the rdocumentation, my idea is to use all.equal
and to print the difference.
https://www.rdocumentation.org/packages/base/versions/3.6.2/topics/all.equal
d45 <- pi*(1/4 + 1:10)
stopifnot(
+ all.equal(tan(d45), rep(1, 10))) # TRUE, but
all (tan(d45) == rep(1, 10)) # FALSE, since not exactly
[1] FALSE
all.equal(tan(d45), rep(1, 10), tolerance = 0) # to see difference
[1] "Mean relative difference: 1.29526e-15"
Unfortunately, I just get "FALSE" not the difference.
r2_resampled <- resample(r2, r1)
compareRaster(r1, r2_resampled)
[1] TRUE
# Compare rasters
result <- all.equal(r1, r2_resampled)
Warning message:
In compareRaster(target, current, ..., values = values, stopiffalse =
stopiffalse, :
not all objects have the same values
print(result)
[1] FALSE
Kind regards
Sibylle
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