R: Derive 1 degree cell IDs

getID {GSIF}

R Documentation

Derive 1 degree cell IDs

Description

Derives ID's of the 1 degree cells in the default land mask for a given polygon defining the spatial domain of interest.

Usage

## S4 method for signature 'SpatialPolygons'
getID(obj, pixsize = 3/3600, empty.tif = FALSE, 
      compress = FALSE, zipname = set.file.extension(tempfile(tmpdir = getwd()), "zip"))

Arguments

`obj`	object of class `"SpatialPolygons"`; must be in geographical coordinates (WGS84)
`pixsize`	grid cell size in decimal degrees (set at 0.0008333333 or 100 m around equator)
`empty.tif`	logical; specify whether a GeoTiff mask file should be created
`compress`	logical; specify whether to compress GeoTiffs
`zipname`	(optional); zip archive file name

Value

The output is a vector of grid cell ID names e.g. W79_N83. These can be further used to automate digital soil mapping for large areas.

Note

This operation can be time consuming for large areas (e.g. continents).

Author(s)

Tomislav Hengl

Examples

library(sp)
## Bounding box for Malawi:
bbox = expand.grid(lon=c(32.67152, 35.915046), lat=c(-17.12721, -9.363796))
bbox[5,] <- bbox[1,]
crs = CRS("+proj=longlat +datum=WGS84")
x <- SpatialPolygons(list(Polygons(list(Polygon(bbox)), ID="1")), proj4string=crs)
ID.lst <- getID(x)

[Package GSIF version 0.5-5 Index]