SubgridStats: Compute statistics for subgrids

In ICvectorfields: Vector Fields from Spatial Time Series of Population Abundance

Compute statistics for subgrids

Description

Functions that facilitate calculation of statistics at the sub-grid level. These may be useful for drivers of movement speed or direction if used in tandem with DispField, DispFieldST, or DispFieldSTall.

Usage

SubgridMoransI(inputrast1, factv1, facth1, rad1 = 1)

SubgridStats(inputrast1, factv1, facth1, statistic = "var")

Arguments

inputrast1	a raster as produced by terra::rast
factv1	an odd integer for the vertical dimension of sub-grids
facth1	an odd integer for the horizontal dimension of sub-grids
rad1	an integer indicating the neighbourhood radius for Moran's I statistic calculations in rows/columns. Any cell within a distance of rad1 cells of the focal cell is considered to be in its neighbourhood.
statistic	desired output statistic: It should be one of "mean", "var", or "sum". Default setting is var.

Details

Note that when using radius to define the neighbourhood in Moran's I calculations, a radius of one corresponds to the rook's neibhourhood. Values that are NA or Inf are not included in calculations of the Moran's I statistic nor in any of the other statistics that can be computed.

Value

A data frame is returned with the following column names: rowcent, colcent, frowmin, frowmax, fcolmin, fcolmax, and a column for the output statistic.

See Also

DispStats and DispMoransIfor functions that compute statistics at presumed source or sink locations in each region of interest.

Examples

(TestMat <- matrix(c(1, 0, 1, 0, 1,
                     0, 1, 0, 1, 0,
                     1, 0, 1, 0, 1,
                     0, 1, 0, 1, 0,
                     1, 0, 1, 0, 1),
                    nrow = 5))

TestRast <- terra::rast(TestMat)
terra::plot(TestRast)

SubgridMoransI(TestRast, factv1 = 5, facth1 = 5, rad1 = 1)
# using rad1 = 1 is equivalent to using the rooks neighbourhood
# and so the output should be -1.

(TestMat <- matrix(c(1, 0, 1, 0, 1,
                    0, 1, 0, 1, 0,
                    1, 0, 1, 0, 1,
                    0, 1, 0, 1, 0,
                    1, 0, 1, 0, 1),
                    nrow = 5))

TestRast <- terra::rast(TestMat)
terra::plot(TestRast)

SubgridStats(TestRast, factv1 = 5, facth1 = 5, statistic = "mean")
SubgridStats(TestRast, factv1 = 5, facth1 = 5, statistic = "var")
SubgridStats(TestRast, factv1 = 5, facth1 = 5, statistic = "sum")

ICvectorfields documentation built on March 18, 2022, 7:34 p.m.