nomove_agg: Direct data aggregation

Description Usage Arguments Details Value Examples

View source: R/nomove_agg.R

Description

Calculate the value for a given function for each cell in a larger resolution grid.

Usage

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nomove_agg(coarse_dat, fine_dat, agg_fun, is_grid = TRUE, quiet = FALSE, ...)

Arguments

coarse_dat

sf, Raster* or Spatial* object. The coarse grain data (response data) across which to calculate the aggregated function

fine_dat

Raster* object. Raster* object. The fine grain data (predictor / covariate data) to aggregate

agg_fun

function The function to apply. The function fun should take multiple numbers, and return a single number. For example mean, modal, min or max. It should also accept a na.rm argument (or ignore it, e.g. as one of the 'dots' arguments. For example, length will fail, but function(x, ...)na.omit(length(x)) works. See Details

is_grid

logical. Use TRUE (default) if g contains only rectangular cells (i.e. a grid). If g is any other polygon file, this should be set to false

quiet

logical. If FALSE (default) and is_grid == TRUE the user gets a warning that the aggregation assumes all cells are rectangular

...

further arguments passed to or from other methods

Details

grainchanger has several built-in functions. Functions currently included are:

Note that nomove_agg can be run in parallel using plan(multiprocess) from the future package.

Value

Raster (if input is Raster) or numeric vector (if input is sp or sf object) containing values calculated for each coarser cell

Examples

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# load required data
data(g_sf)
data(cont_ls)
data(cat_ls)

# aggregate using mean
d <- nomove_agg(g_sf, cont_ls, mean)

# aggregate using Shannon evenness
d <- nomove_agg(g_sf, cont_ls, shei, lc_class = 1:4)

grainchanger documentation built on Feb. 1, 2021, 5:07 p.m.