osmplotr (version 0.2.0)

colour_mat: colour_mat

Description

Generates a 2D matrix of graduated colours by interpolating between the given colours specifying the four corners.

Usage

colour_mat(n = c(10, 10), cols, rotate, plot = FALSE)

Arguments

n

number of rows and columns of colour matrix (default = 10; if length 2, then dimensions of rectangle).

cols

vector of length >= 4 of colors (example, default = rainbow (4), or from RColorBrewer, brewer.pal (4, 'Set1')). cols are wrapped clockwise around the corners from top left to bottom left.

rotate

rotates the entire colour matrix by the specified angle (in degrees).

plot

plots the colour matrix

Value

• matrix of colours

See Also

add_osm_groups.

Examples

cm <- colour_mat (n=5, cols=rainbow(4), rotate=90, plot=TRUE)

# 'colour_mat' is intended primarily for use in colouring groups added with
# 'add_osm_groups' using the 'colmat=TRUE' option:
bbox <- get_bbox (c (-0.13, 51.5, -0.11, 51.52))
# Generate random points to serve as group centres
set.seed (2)
ngroups <- 6
x <- bbox [1,1] + runif (ngroups) * diff (bbox [1,])
y <- bbox [2,1] + runif (ngroups) * diff (bbox [2,])
groups <- cbind (x, y)
groups <- apply (groups, 1, function (i) 
                 sp::SpatialPoints (matrix (i, nrow=1, ncol=2)))
# plot a basemap and add groups
map <- plot_osm_basemap (bbox=bbox, bg="gray20")
map <- add_osm_groups (map, obj=london$dat_BNR, group=groups, cols=rainbow (4),
                       colmat=TRUE, rotate=90)
print (map)