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Crosswalk between two spatial resolutions through the atom layer

Source: R/map.R
geoscale_map.Rd

Materialises the from -> atoms -> to route as a table: one row per pair of overlapping regions with

Usage

geoscale_map(from, to, gs = NULL, weight = NULL)

Arguments

from, to

Either two geoframe names of gs (within-object map), or two named Geoscale objects (cross-object map on shared atom region keys).

gs

The Geoscale the geoframe names belong to; required for the within-object shape, ignored otherwise.

weight

Weight column for w. NULL uses the default weight; when the object declares no weights at all, every atom gets weight 1 (an equal split).

Value

A data.frame with columns <from>, <to> (NA = uncovered by to), n_from, n_overlap, w, w_from.

Details

  • n_from – atoms in the from region (its full set, before any target coverage is considered),

  • n_overlap – atoms the pair shares,

  • w – the weight of the overlap (summed atom weights, chosen weight column), the quantity "weighted_mean" aggregation uses,

  • w_from – the full weight of the from region; w / w_from is the split share "sum" disaggregation uses.

The two label columns are named by the geoframes (within one Geoscale) or by the Geoscale names (across two); rows with an NA target label are atoms to does not cover. A crosswalk registered with register_geoscale_map() is returned as-is instead of being derived.

Examples

gs <- geoscale_example()
geoscale_map("state", "zone", gs = gs)
#>   state zone n_from n_overlap   w w_from
#> 1    N1   N1      2         2 300    300
#> 2    N2   ZB      2         2 700    700
#> 3    S1   ZB      2         1 500   1100
#> 4    S1   ZC      2         1 600   1100
geoscale_map("country", "state", gs = gs, weight = "km2")
#>   country state n_from n_overlap    w w_from
#> 1       N    N1      4         2  300   1000
#> 2       N    N2      4         2  700   1000
#> 3       S    S1      2         2 1100   1100