Register / look up a direct spatial crosswalk

A registered map short-circuits the atom-layer derivation in geoscale_map() or geoscale_map_between() (and thereby recast_geoscale()) for one pair of resolutions – for cases where the exact correspondence is known (hand-audited crosswalks, official concordance tables).

Usage

register_geoscale_map(gs, from, to, map)

register_geoscale_map_between(from, to, map)

get_geoscale_map(gs, from, to)

get_geoscale_map_between(from, to)

list_geoscale_maps()

Arguments

gs

The GeoScale the geoframes belong to, or its name.

from, to

For the within-object functions, geoframe names of gs. For the _between functions, two GeoScale objects or their names.

map

A data.frame shaped like a geoscale_map() result: the two label columns named after the geoframes (or GeoScales), plus n_from, n_overlap, w and w_from. NULL removes a previously registered map.

Value

Invisibly, the registry key. The get_ functions return the registered map (or NULL); list_geoscale_maps() a data.frame of registry keys.

Details

register_geoscale_map() and get_geoscale_map() handle a pair of geoframes of one GeoScale; the map is scoped to that object, so "state" -> "zone" maps of two different objects do not collide. register_geoscale_map_between() and get_geoscale_map_between() handle a pair of GeoScales.

Examples

gs <- geoscale_example()
fake <- data.frame(state = "N1", zone = "ZC", n_from = 1L,
                   n_overlap = 1L, w = 1, w_from = 1)
register_geoscale_map(gs, "state", "zone", fake)
list_geoscale_maps()
#>                   key
#> 1 example:state->zone
get_geoscale_map(gs, "state", "zone")
#>   state zone n_from n_overlap w w_from
#> 1    N1   ZC      1         1 1      1
register_geoscale_map(gs, "state", "zone", NULL)  # remove
clear_geoscale_maps()