Breaking changes
max_method sets how the maximum spatial separation (spatial_separation_max) is found. The new default, "exact", searches for the true maximum, which is guaranteed for Euclidean distances between centroids (see ?uci). The previous approaches underestimated it by an amount that depends on the shape of the area; they remain available as "heuristic" (old default) and "bootstrap", and reproduce earlier results. The argument bootstrap_border is deprecated.Major changes
uci() is faster and uses much less memory, especially with dist_type = "spatial_link" and the bootstrap. Results are unchanged.parallel now sets the number of threads for shortest-path distances (dist_type = "spatial_link" only). The default, FALSE, uses one thread; previously all cores were used.Minor changes
remove_islands() and argument uci(remove_islands = TRUE) keep only the largest group of contiguous polygons, so "spatial_link" works in areas with islands.uci() now warns when dist_type = "euclidean" and the study area is markedly concave or has a large gap inside it (e.g. a bay or a lake), suggesting "spatial_link" (#11).grid_rio.rds, a hexagonal grid of Rio de Janeiro with a concave outline and islands.NA, empty or non-polygon geometries, and non-contiguous polygons with "spatial_link".uci() now accepts columns with NA values. In such cases, NAs are replaced with zero as they represent zero activities.spdep::poly2nb(geo, queen=TRUE)) to determine neighboring polygons whe considering spatial link distances.Major changes
uci function now has a new parameter dist_type that allows users to choose whether calculations should be based on "euclidean" distances (Default) or "spatial_link" distances. Spatial link distances consider Euclidean distances along the links of spatial neighbour links. In the case of areas with a concave shape (like a bay), it is strongly recommended to use "spatial_link" distances (even though they are computationally more costly) because simple Euclidean distances can bias UCI estimates in those cases.uci function now has a new parameter parallel that speeds up calculations for large areas comprised with many polygons.Minor changes