Prepare an aggregated lon/lat raster for climate-grid retrieval

Extends a template raster to a target extent, reprojects it to a geographic (lon/lat, EPSG:4326) coordinate reference system, and aggregates it to an approximate target resolution. This is used to prepare a coarse point grid for climate-data retrieval (e.g. BioSIM, ERA5).

prep_agg_lonlat_raster(ext, rtm, agg_to = 1000)

Arguments

ext

A SpatExtent (or object coercible to one by terra::extend()) giving the target extent.

rtm

A SpatRaster template ("raster to match") supplying the source resolution and CRS.

agg_to

Numeric. Target resolution (in the units of rtm) used to compute the aggregation factor relative to terra::res(rtm). Defaults to 1000.

Value

A SpatRaster extended, reprojected to EPSG:4326, and aggregated.

See also

Other spatial helpers: calc_centroid(), create_bbox(), extract_coords(), save_gpkg(), spatial_join_intersects()

Examples

r <- terra::rast(
  xmin = 0, xmax = 100, ymin = 0, ymax = 100,
  resolution = 10, crs = "epsg:3005"
)
terra::values(r) <- seq_len(terra::ncell(r))
prep_agg_lonlat_raster(terra::ext(r), r, agg_to = 50)
#> class       : SpatRaster
#> size        : 2, 3, 1  (nrow, ncol, nlyr)
#> resolution  : 0.0005704349, 0.0005704349  (x, y)
#> extent      : -138.4461, -138.4444, 44.19935, 44.20049  (xmin, xmax, ymin, ymax)
#> coord. ref. : lon/lat WGS 84 (EPSG:4326)
#> source(s)   : memory
#> name        : lyr.1
#> min value   :   NaN
#> max value   :   NaN