selectGridcells: Select gridcells
In MagicForrest/DGVMTools: DGVM Processing, Analysis and Plotting Tools

selectGridcells

R Documentation

Select gridcells

Description

Select gridcells from a Field (or a data.table or a data.frame) using either gridcell coordinates or polgyons (from, for example, a shapefile).

Usage

selectGridcells(
  x,
  gridcells,
  spatial.extent.id = NULL,
  tolerance = NULL,
  decimal.places = NULL,
  cover.threshold = NULL,
  ...
)

Arguments

`x`	The Field, data.table or data.frame from which the gridcells should be selected. Note that a data.table or data.frame should have columns "Lon" and "Lat" included.
`gridcells`	The gridcells to be extracted. These can be specified as one of the following: A simple two-element numeric to pull out one gridcell (ordering is lon, lat) A data.frame or data.table in which the first two columns are assumed to be longitude and latitude. An sf:sf object. By default points will be selected that lie under a polygon (feature), but see the argument `cover.threshold` to select based on an overlap threshold. Note also that is very easy to get sf objects representing countries from the rnaturalearth package, which, in combination with this function, provides a very easy way to subset by country.
`spatial.extent.id`	A character string to describe the gridcells selected. When selecting gridcells from a Field you must specify a `spatial.extent.id` for meta-data consistency (you have free choice here, but avoid spaces).
`tolerance`	A single numeric specifying how close a required gridcell in gridcells must be to one in `x`. Doesn't currently work, non-exact matching is not implemented! Contact the author if this is a critical feature for you.
`decimal.places`	A single numeric specifying how many decimal place to which the coordinates should rounded to facilitate a match. If not specified not rounding is done.
`cover.threshold`	An optional numeric specifying what fraction of the gridcell must be covered by a feature in the case the `gricells` argument is a SpatialPolygonsDataFrame. Note that is done using the `getCover` argument of `raster::rasterize()` which is only sensitive to about 1% cover. fractions
`...`	Further arguments. Currently not used.