leafletR (version 0.1-2)

styleGrad: Graduated styling

Description

Creates a graduated style based on an attribute.

Usage

styleGrad(prop, breaks, right=TRUE, out=0, 
  style.par, style.val, leg, ...)
grads(prop, breaks, right=TRUE, out=0, 
  style.par, style.val, leg, ...)

Arguments

prop

Property (attribute) of the data to be styled, as string.

breaks

A vector giving the breakpoints between the desired classes.

right

If TRUE (default) classes are right-closed (left-open) intervals (>= breakpoint). Otherwise classes are left-closed (right-open) intervals (> breakpoint).

out

Handling of data outside the edges of breaks. One of 0 (left and right-closed), 1 (left-closed, right-open), 2 (left-open, right-closed) or 3 (left and right-open). Default is 0

style.par

Styling parameter as string. One of "col" (graduated color) or "rad" (graduated radius). Graduated radius can only be applied to points.

style.val

Styling values, a vector of colors or radii applied to the classes.

leg

Legend title as string. The line break sequence \n may be used for line splitting.

...

Additional styling parameters, see styleSingle for details.

Value

• A graduated style object.

encoding

UTF-8

See Also

styleSingle, styleCat, leaflet

Examples

# prepare data
data(quakes)
qks <- toGeoJSON(data=quakes, dest=tempdir())

# prepare style
range(quakes$mag)	# gives 4.0 and 6.4
sty <- styleGrad(prop="mag", breaks=seq(4, 6.5, by=0.5), 
  style.val=rev(heat.colors(5)), leg="Richter Magnitude")

# create map
map <- leaflet(data=qks, dest=tempdir(), 
  title="Fiji Earthquakes", style=sty)
browseURL(map)

# left-closed intervals
# note the gray points on the map: magnitude of 4 is outside the breaks
# (which are >4.0, >4.5, >5.0, >5.5, >6.0 and >6.5)
sty <- styleGrad(prop="mag", breaks=seq(4, 6.5, by=0.5), right=FALSE, 
  style.val=rev(heat.colors(5)), leg="Richter Magnitude")
map <- leaflet(data=qks, dest=tempdir(), 
  title="Fiji Earthquakes", style=sty)
browseURL(map)

# handle outliers
# include outliers of the upper example by left-opening the break edges 
# and adding a sixth color
sty <- styleGrad(prop="mag", breaks=seq(4, 6.5, by=0.5), right=FALSE, 
  out=2, style.val=rev(heat.colors(6)), leg="Richter Magnitude")
map <- leaflet(data=qks, dest=tempdir(), 
  title="Fiji Earthquakes", style=sty)
browseURL(map)

# graduated radius
sty <- styleGrad(prop="mag", breaks=seq(4, 6.5, by=0.5), style.par="rad", 
  style.val=c(2,5,9,14,20), leg="Richter Magnitude")
map <- leaflet(data=qks, dest=tempdir(), 
  title="Fiji Earthquakes", style=sty)
browseURL(map)

# additional styling parameters
peak <- toGeoJSON(data=system.file(package="leafletR", "files", 
  "peak_sk.kml"), dest=tempdir())
sty <- styleGrad(prop="Name", breaks=seq(750, 2500, by=250), out=3, 
  style.val=terrain.colors(9), leg="Elevation", 
  col=NA, fill.alpha=1, rad=3)
map <- leaflet(data=peak, dest=tempdir(), title="Peak elevation", 
  base.map="mqsat", style=sty, popup="Name")
browseURL(map)