match_raster_colors: Match colors in RasterLayer color space to the provided...

In pfrater/arcpullr: Pull Data from an 'ArcGIS REST' API

Match colors in RasterLayer color space to the provided legend values

Description

Colors provided by the legend do not always correspond exactly with the colors in the colortable of a RasterLayer object. They are usually pretty close, though, so this function finds the closest colors, maps them to the appropriate colors in the Raster* object, and applies that to the legend.

Usage

match_raster_colors(legend, x)

Arguments

legend	An object of class raster_legend as returned by get_layer_legend
x	A RasterLayer object as returned by get_map_layer

Details

Raster colors in x are mapped to those in legend by converting the RGB hexadecimal values to a 3D vector of values for red, green and blue. The closest values are then assigned using 3D Pythagorean theorem to compute the distance among all colors. The minimum distance in three dimensional space is the color in x that gets mapped to the appropriate color in legend.

Value

A raster_legend object with corrected colors to match those in x

Examples

## Not run: 
wi_landcover <- get_map_layer(wi_landcover_url, wis_poly)
legend <- get_layer_legend(wi_landcover_url)
new_legend <- match_raster_colors(legend, wi_landcover_url)

## End(Not run)

pfrater/arcpullr documentation built on March 16, 2024, 6:29 a.m.