Look up an ESDB raster value at WGS84 coordinates

Loads the requested attribute raster, reprojects WGS84 lat/lon input to the raster's native CRS (typically LAEA Europe, EPSG:3035), and extracts the value(s). When a Value Attribute Table (`.vat.dbf`) is available, the integer raster value is decoded to its coded string (e.g. `21` -> `"LV"` -> Luvisol).

Usage

lookup_esdb(coords, attribute, raster_root, decode = TRUE)

Arguments

coords

A two-column matrix or data.frame with `lon` and `lat` (WGS84 decimal degrees) – in that order. A single c(lon, lat) vector is also accepted.

attribute

Name of the ESDB attribute folder, e.g. "WRBLV1" or "WRBFU". See available_esdb_attributes.

raster_root

Path to the unpacked ESDB raster directory.

decode

If TRUE (default), decode the integer raster value to the VAT-coded string (e.g. "21" -> "LV"). If FALSE, return the raw integer.

Value

Character vector (decoded codes) or numeric vector (raw values) of the same length as nrow(coords). NA for points outside the raster footprint.

Details

Coordinates outside the European raster footprint return `NA` silently (rather than erroring) so vectorised calls degrade gracefully.

See also

available_esdb_attributes

Examples

if (FALSE) { # \dontrun{
root <- "~/data/ESDB-Raster-Library-1k-GeoTIFF-20240507"

# Single point: Wageningen, Netherlands (5.66 E, 51.97 N)
lookup_esdb(c(5.66, 51.97), "WRBLV1", root)
#> [1] "GL"   # Gleysol per the ESDB 1km raster

# Vector: Lisbon + Berlin + Helsinki
coords <- rbind(c(-9.14, 38.72), c(13.40, 52.52), c(24.94, 60.17))
lookup_esdb(coords, "WRBLV1", root)
#> [1] "CM" "LV" "PZ"   # Cambisol, Luvisol, Podzol
} # }