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Put a layer on a grid, whichever form it arrives in

Source: R/terra-connectivity.R
onto_grid.Rd

A vector layer is rasterised; a SpatRaster is already cells, so it is resampled onto the grid instead. This is the one place that decides what an empty cell means, which is why background is required: NA for habitat, because a cell with no habitat in it has no value, and 0 for a barrier, because a cell with no barrier in it is not blocked.

Usage

onto_grid(layer, grid, background)

Arguments

layer

An sf, SpatVector or SpatRaster layer.

grid

A SpatRaster whose geometry the result takes, from empty_grid() or an already-prepared layer.

background

Value for cells the layer does not cover. Ignored when layer is a SpatRaster, which brings its own.

Value

A SpatRaster on grid's geometry.

Details

Use it to put a scenario layer on the grid of the layer it replaces. A scenario rasterised onto a grid of its own extent is a different landscape, and habitat_connectivity_comparison() will refuse to compare it.

See also

prepare_rasters(), which uses this for both of its layers.

Examples

grid <- empty_grid(example_barrier_shp(), resolution = 10)
#> Reading layer `lizard_barrier' from data source 
#>   `/home/runner/work/_temp/Library/urbioconnect/ex/lizard_barrier.shp' 
#>   using driver `ESRI Shapefile'
#> Simple feature collection with 1 feature and 1 field
#> Geometry type: MULTIPOLYGON
#> Dimension:     XY
#> Bounding box:  xmin: 326089.6 ymin: 5820342 xmax: 327662.5 ymax: 5821909
#> Projected CRS: GDA94 / MGA zone 55

# a vector layer is rasterised
onto_grid(example_barrier_shp(), grid, background = 0)
#> Reading layer `lizard_barrier' from data source 
#>   `/home/runner/work/_temp/Library/urbioconnect/ex/lizard_barrier.shp' 
#>   using driver `ESRI Shapefile'
#> Simple feature collection with 1 feature and 1 field
#> Geometry type: MULTIPOLYGON
#> Dimension:     XY
#> Bounding box:  xmin: 326089.6 ymin: 5820342 xmax: 327662.5 ymax: 5821909
#> Projected CRS: GDA94 / MGA zone 55
#> class       : SpatRaster
#> size        : 157, 157, 1  (nrow, ncol, nlyr)
#> resolution  : 10.0184, 9.979108  (x, y)
#> extent      : 326089.6, 327662.5, 5820342, 5821909  (xmin, xmax, ymin, ymax)
#> coord. ref. : GDA94 / MGA zone 55 (EPSG:28355)
#> source(s)   : memory
#> name        : layer
#> min value   :     0
#> max value   :     1

# a raster one is resampled
onto_grid(example_habitat(), grid, background = NA)
#> class       : SpatRaster
#> size        : 157, 157, 1  (nrow, ncol, nlyr)
#> resolution  : 10.0184, 9.979108  (x, y)
#> extent      : 326089.6, 327662.5, 5820342, 5821909  (xmin, xmax, ymin, ymax)
#> coord. ref. : GDA94 / MGA zone 55 (EPSG:28355)
#> source(s)   : memory
#> name        : Pseudo Layer
#> min value   :            1
#> max value   :            1