Compare attributes of two SpatRaster objects — compare

Two SpatRaster objects are compatible (in terms of combining layers) if the CRS, extent and resolution are similar. In those cases you can combine the objects simply as c(x, y).

This function compares those attributes and reports the results. See Resolving differences for minimal guidance.

Usage

compare_spatrasters(x, y, digits = 6)

Arguments

x, y: SpatRaster objects.
digits: Integer to set the precision for comparing the extent and the resolution.

Value

An invisible logical value indicating whether the SpatRaster objects are compatible, plus an informative message flagging any issues found.

terra equivalent

terra::compareGeom().

Resolving differences

For a different CRS, try terra::project().
For a different extent, try terra::resample().
For a different resolution, try terra::resample(), terra::aggregate() or terra::disagg().

Examples

library(terra)

x <- rast(matrix(1:90, ncol = 3), crs = "EPSG:3857")

# Nothing
compare_spatrasters(x, x)

# Different CRS
y_nocrs <- x
crs(y_nocrs) <- NA

compare_spatrasters(x, y_nocrs)
#> ! Results of `tidyterra::compare_spatrasters()`: 
#> The following attributes are not equal:
#> • CRS

# Different extent
compare_spatrasters(x, x[1:10, , drop = FALSE])
#> ! Results of `tidyterra::compare_spatrasters()`: 
#> The following attributes are not equal:
#> • extent

# Different resolution
y_newres <- x

res(y_newres) <- res(x) / 2
compare_spatrasters(x, y_newres)
#> ! Results of `tidyterra::compare_spatrasters()`: 
#> The following attributes are not equal:
#> • resolution

# Everything

compare_spatrasters(x, project(x, "epsg:3035"))
#> ! Results of `tidyterra::compare_spatrasters()`: 
#> The following attributes are not equal:
#> • CRS
#> • extent
#> • resolution