choro.legend: choro.legend

In GISTools: Some further GIS capabilities for R

Description

Draw a legend for a choropleth map.

Usage

choro.legend(px, py, sh, under = "under", over = "over", 
  between = "to", fmt = "%g", cex=1, ...)

Arguments

px	x coordinate of legend location
py	y coordinate of legend location
sh	Shading scheme object used as basis for the legend
under	What to write in front of the lowest choropleth class upper limit.
over	What to write in front of the highest choropleth class lower limit.
between	What to write between the upper and lower limits of intermediate chropleth classes.
fmt	C style format for values stated in above choroplth class limits.
cex	Relative size of text in the legend.
...	Other arguments, passed on to the generic legend function.

Details

Returns no value, but draws a choropleth map legend on the current graphics device as a side effect

Value

None (see above)

Author(s)

Chris Brunsdon

See Also

choropleth, auto.shading, shading.

Examples

# Read in map data and compute a rate for mapping
sids <- readShapePoly(system.file("shapes/sids.shp", package="maptools")[1], 
	proj4string=CRS("+proj=longlat +ellps=clrk66"))
sids.rate=10000*sids@data[,10]/sids@data[,9]
# Create the shading scheme,  plot a choropleth map and add a legend
shades = auto.shading(sids.rate)
choropleth(sids,sids.rate,shades)
choro.legend(-83.77,37.87,shades,fmt="%4.1f",cex=0.8,title='Rate per 10,000')

Example output

Loading required package: maptools
Loading required package: sp
Checking rgeos availability: TRUE
Loading required package: RColorBrewer
Loading required package: MASS
Loading required package: rgeos
rgeos version: 0.3-23, (SVN revision 546)
 GEOS runtime version: 3.4.2-CAPI-1.8.2 r3921 
 Linking to sp version: 1.2-3 
 Polygon checking: TRUE 

NOTE: rgdal::checkCRSArgs: no proj_defs.dat in PROJ.4 shared files
Warning message:
use rgdal::readOGR or sf::st_read 

GISTools documentation built on May 6, 2019, 1:09 a.m.