gshhsMask: A land mask based on the GSHHS data set

In SWotherspoon/RWalc: Continuous-Time Correlated Random Walk Models for Animal Movement

Description

Generate a land mask function based on the Global Self-consistent, Hierarchical, High-resolution Geography Database. The mask is provided at two (approximate) spatial resolutions: 0.1 degree and 0.05 degrees. The latter requires significantly more memory.

Usage

gshhsMask(res = c("0.1", "0.05"), land = FALSE, latmin = -90, latmax = 90)

Arguments

res	The spatial resolution of the mask, in degrees.
land	The logical value returned for land.
latmin	The minimum allowable latitude.
latmax	The maximum allowable latitude.

Details

Returns a function of three arguments

tm		time
lon		longitude
lat		latitude

suitable for use with rwalcSimulate. This mask is actually independent of time and the tm argument to the mask is ignored.

Value

A function of three arguments (tm,lon,lat) that returns a logical indicating whether (lon,lat) is at sea or on land and inside the allowable latitude range.

References

Wessel, P., and W. H. F. Smith, A Global Self-consistent, Hierarchical, High-resolution Shoreline Database, J. Geophys. Res., 101, #B4, pp. 8741-8743, 1996. https://www.ngdc.noaa.gov/mgg/shorelines/gshhs.html

See Also

rwalc

Examples

mask  <- gshhsMask() ## initialize land mask function
mask(0,100,-65) ## test point - time lon,lat

SWotherspoon/RWalc documentation built on Feb. 25, 2021, 8:26 p.m.