Description Usage Arguments Details Value Author(s) Examples
Given a matrix of quadrature points and a list of species presences, this function extracts environmental data to presence locations using bilinear interpolation.
1 |
sp.xy |
A matrix of species locations containing at least one column representing longitude and one column representing latitude. |
env.grid |
The geo-referenced matrix of environmental grids. |
env.scale |
The spatial resolution of the quadrature scheme from which the environmental data is extracted. |
coord |
A vector containing the names of the longitude and latitude coordinates,
as in |
file.name |
An optional argument containing the name of the saved file. Setting
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At a given species location with coordinates (x, y), the interpolated value of the
environmental variable z is calculated as a weighted average of z at four reference
quadrature points (x^{(1)}, y^{(1)}), (x^{(1)}, y^{(2)}), (x^{(2)}, y^{(1)}) and (x^{(2)}, y^{(2)})
that form a square of nominated side length env.scale
surrounding (x, y).
A matrix containing locations of species presences in the first two columns and the interpolated environmental data in the remaining columns.
Ian W. Renner
1 2 3 | data(BlueMountains)
species.env = env.var(BlueMountains$eucalypt, env.grid = BlueMountains$env, env.scale = 0.5,
file.name = "Sp Env Data")
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