Suitability to deme size transformation functions

Brief overview

All transformations are performed on a raster with 0-1 suitability values (or a raster that will be normalized to 0-1). The output of the transformation is an array of the same shape as the input raster, but with values transformed according to the specified function.

The “linear” transformation multiplies the input values by the maximum local deme size (max_local_size).

The “threshold” transformation creates an array where values below the threshold value are set to zero and values about the threshold value are set to 1.

The “sigmoid” transformation applies a sigmoid function to the data using Eq. 1 from Frazier and Wang 2013, Modeling landscape structure response across a gradient of land cover intensity, where an inflection_point and slope are specified. The inflection_point can be thought of like a threshold value, where original values below this value descend quicker to zero, and values about this value increase quicker to 1. The slope determines how fast values change on either side of the inflection point. A sufficiently steep slope makes this a threshold function, while a sufficiently shallow slope makes this a linear function.