Some models are artificially bounded

[jcoliver]

Some funkiness is going on with models where one or more of the species' ranges are not realistic (i.e. portions of the range border is a long straight line). See scripts/examples/Papilio_cresphontes-future-sdm-pairwise.R and scripts/examples/Papilio_cresphontes-sdm-pairwise.R for an examples.
Note western and eastern border for plant in: Papilio_cresphontes-pairwise-prediction.pdf

[jcoliver]

Likely caused by cropping the bioclim variables by the geographic extent of the observations. Bioclim data are tiled, so cropping might exclude tiles outside geographic extent of observations. Lines 76-88 of scripts/examples/Zanthoxylum_americanum-sdm-single.R:

# Determine geographic extent of our data
max.lat = ceiling(max(obs.data$lat))
min.lat = floor(min(obs.data$lat))
max.lon = ceiling(max(obs.data$lon))
min.lon = floor(min(obs.data$lon))
geographic.extent <- extent(x = c(min.lon, max.lon, min.lat, max.lat))

# Get the biolim data
bioclim.data <- getData(name = "worldclim",
                        var = "bio",
                        res = 2.5,
                        path = "data/")
bioclim.data <- crop(x = bioclim.data, y = geographic.extent)

[jcoliver]

Easiest quick fix is probably to just buffer the crop area by padding the geographic.extent used in the crop call.

[jcoliver]

Added some padding to extents, but the 10% default may not be enough. See scripts/examples/Papilio_cresphontes-future-sdm-single.R; the eastern boundary appears to still suffer from the arbitrary cutoff.