legend.gradient: Legend Gradient

In SDMTools: Species Distribution Modelling Tools: Tools for processing data associated with species distribution modelling exercises

Description

legend.gradient creates and displays a gradient legend on a plot or image file. The place and size of the legend is defined by coordinates, previously identified.

Usage

legend.gradient(pnts, cols = heat.colors(100), limits = c(0, 1),
  title = "Legend", ...)

Arguments

pnts	x and y coordinates of the gradient location in the plot
cols	a set of 2 or more colors used in the image, to create the gradient
limits	to label the min and max values of the gradient in the legend
title	to specify the title of the legend
...	other graphical parameters defined by image() or plot()

Value

nothing is returned, a gradient legend is added to a plot or a image.

Author(s)

Lorena Falconi [e-mail]

Examples

#define a simple binary matrix
tmat = { matrix(c( 0,0,0,1,0,0,1,1,0,1,
                   0,0,1,0,1,0,0,0,0,0,
                   0,1,NA,1,0,1,0,0,0,1,
                   1,0,1,1,1,0,1,0,0,1,
                   0,1,0,1,0,1,0,0,0,1,
                   0,0,1,0,1,0,0,1,1,0,
                   1,0,0,1,0,0,1,0,0,0,
                   0,1,0,0,0,1,0,NA,NA,NA,
                   0,0,1,1,1,0,0,NA,NA,NA,
                   1,1,1,0,0,0,0,NA,NA,NA),nr=10,byrow=TRUE) }

#do the connected component labeling
tasc = ConnCompLabel(tmat)

# Create a color ramp
colormap=c("grey","yellow","yellowgreen","olivedrab1","lightblue4")

#create an image
image(tasc,col=colormap, axes=FALSE, xlab="", ylab="", ann=FALSE)

#points for the gradient legend
pnts = cbind(x =c(0.8,0.9,0.9,0.8), y =c(1.0,1.0,0.8,0.8))

#create the gradient legend
legend.gradient(pnts,colormap,c("Low","High"))

Example output

SDMTools documentation built on Jan. 11, 2020, 9:23 a.m.