Create distance layer.
Creates a layer depicting distances to records using the minimum, average, distance to the minimum convex polygon or distance taking into account a cost surface.
raster.distance(longlat, layers, type = "minimum")
longlat |
Matrix of longitude and latitude or eastness and northness (two columns in this order) of species occurrence records. |
layers |
Raster* object as defined by package raster to serve as model to create distance layer. Cost surface in case of param ="cost". |
type |
text string indicating whether the output should be the "minimum", "average", "mcp" or "cost" distance to all records. "mcp" means the distance to the minimum convex polygon encompassing all records. |
Using distance to records in models may help limiting the extrapolation of the predicted area much beyond known areas.
A RasterLayer object.
data(red.layers) alt = red.layers[[3]] data(red.records) par(mfrow=c(3,2)) raster::plot(alt) points(red.records) raster::plot(raster.distance(red.records, alt)) raster::plot(raster.distance(red.records, alt, type = "average")) raster::plot(raster.distance(red.records, alt, type = "mcp")) raster::plot(raster.distance(red.records, alt, type = "cost"))
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