osmplotr (version 0.2.0)

adjust_colours: adjust_colours

Description

Adjusts a given colour by lightening or darkening it by the specified amount (relative scale of -1 to 1). Adjustments are made in RGB space, for limitations of which see ?convertColor

Usage

adjust_colours(cols, adj = 0, plot = FALSE)

Arguments

cols

A vector of R colours (for allowable formats of which, see ?col2rgb).

adj

A number between -1 and 1 determining how much to lighten (positive values) or darken (negative values) the colours.

plot

If true, generates a plot to allow visual comparison of original and adjusted colours

Value

• Corresponding vector of adjusted colours (as hexadecimal strings)

See Also

osm_structures, link[grDevices]{col2rgb}.

Examples

cols <- adjust_colours (cols=heat.colors (10), adj=-0.2, plot=TRUE)

# 'adjust_colours' also offers an easy way to adjust the default colour
# schemes provided by 'osm_structures'. The following lines darken the
# highway colour of the 'light' colour scheme by 20\%
structures <- osm_structures (structures=c('building', 'highway', 'park'),
                              col_scheme='light')
structures$cols [2] <- adjust_colours (structures$cols [2], adj=-0.2)
# Plot these structures:
bbox <- get_bbox (c (-0.13, 51.5, -0.11, 51.52))
dat_B <- extract_osm_objects (value='building', bbox=bbox)
dat_H <- extract_osm_objects (value='highway', bbox=bbox)
dat_P <- extract_osm_objects (value='park', bbox=bbox)
# These data are also included in the 'london' data of 'osmplotr'
osm_data <- list (dat_B=london$dat_BNR, dat_H=london$dat_HP, dat_P=london$dat_P)
dat <- make_osm_map (structures=structures, osm_data=osm_data, bbox=bbox)
print (dat$map)