scaleBar: Scale bar and inset map

In mapmisc: Utilities for Producing Maps

Scale bar and inset map

Description

Utilities for plotting a map, adding a scale bar and north arrow, and adding a legend of colour scales.

Usage

scaleBar(crs, pos = "bottomright",   
	cex=1,
    pt.cex = 1.1*cex,
    seg.len=5*cex,
    title.cex=cex,
    outer=TRUE,...)
insetMap(crs, pos="bottomright",map="osm",zoom=0, 
		width=max(c(0.2, 1-par('plt')[2])), 
		col="#FF000090", borderMap=NULL,
			cropInset = terra::ext(-180, 180,  -47, 71),
			outer=TRUE, inset = c(0.1, 0.1), ...) 

Arguments

crs	A character string from which a projection can be extracted with terra::crs
pos	Position, as specified in the legend function.
cex	scaling factor for the legend
pt.cex	Scaling factor north arrow (can be zero).
seg.len	approximate length (in character units) of the scale bar. can be zero.
title.cex	scaling for the distance text
outer	If TRUE, put bar or map in the margin of the plot
map	Either a Raster for the inset map or a string passed to openmap's path argument
zoom	Zoom level if retrieving inset map from openmap
width	Width of the inset map, as a fraction of the plot window
col	Colour for shaded region of inset map
borderMap	border style for the inset map (passed to polygon)
cropInset	Crop the insert map to this extent
inset	how far from the border to put the inset map
...	Additional arguments passed to legend for scaleBar or polygon (for insetMap).

Details

scaleBar produces a scale bar reflecting the distance travelling on a great circle from the centre of the plot and travelling to the right. The length of the bar is the width of 6 characters times scale.cex.

Value

A list containig coordinates of the elements of the scale bar.

Author(s)

Patrick Brown

Examples

Npoints = 20
set.seed(0)
myPoints = vect(
	cbind(runif(Npoints)-0.1, 51+runif(Npoints)), 
	atts=data.frame(
		y1=c(NA, rnorm(Npoints-1)), 
	    y2=c(sample(0:5, Npoints-1,replace=TRUE), NA)
	),
	crs=crsLL)



breaks = c(-100, -1, 1, Inf)
thecol = c('red','orange','blue')


oldpar = map.new(myPoints)
plot(myPoints,col = as.character(cut(
	myPoints$y1, breaks, thecol
)),add=TRUE)
scaleBar(myPoints, "bottomright",cex=1.25, seg.len=2)
legendBreaks("topleft", legend=breaks, col=thecol)

thedot = insetMap(crs=myPoints, pos="bottomleft",
	 col='#00000000', lty=0, outer=FALSE, width=0.5)
points(thedot)

par(oldpar)

mapmisc documentation built on Nov. 21, 2023, 5:09 p.m.