cartography (version 1.3.0)

dotDensityLayer: Dot Density layer

Description

Plot a dot density layer.

Usage

dotDensityLayer(spdf, df, spdfid = NULL, dfid = NULL, var, n = NULL, iter = 5, pch = 1, cex = 0.15, type = "random", col = "black", legend.pos = "topright", legend.txt = NULL, legend.cex = 0.6, legend.col = "black", legend.frame = TRUE, add = TRUE)

Arguments

spdf

SpatialPointsDataFrame or SpatialPolygonsDataFrame; if spdf is a SpatialPolygonsDataFrame symbols are plotted on centroids.

df

data frame; df contains the values to plot.

spdfid

id field in spdf, default to the first column of the spdf data frame. (optional)

dfid

id field in df, default to the first column of df. (optional)

var

name of the numeric field in df to plot.

n

one dot on the map represents n (in var units).

iter

number of iteration to try to locate sample points (see Details).

pch

symbol to use: points.

cex

size of the symbols

type

points allocation method: "random" or "regular" (see Details).

col

color of the points.

legend.pos

"topright", "left", "right", "bottomleft", "bottom", "bottomright". If legend.pos is "n" then the legend is not plotted.

legend.txt

text in the legend.

legend.cex

size of the legend text.

legend.col

color of the text in the legend.

legend.frame

whether to add a frame to the legend (TRUE) or not (FALSE).

add

whether to add the layer to an existing plot (TRUE) or not (FALSE).

Details

The iter parameter is defined within the spsample function. If an error occurred, increase this value. The type parameters is defined within the spsample function.

See Also

propSymbolsLayer

Examples

data("nuts2006")
# Example 1
plot(nuts0.spdf)
dotDensityLayer(spdf = nuts0.spdf, df=nuts0.df,var="pop2008")


# Example 2
layoutLayer(title = "Population in Europe, 2008", 
            sources = "Eurostat, 2008", 
            scale = NULL, 
            frame = TRUE,
            col = "black", 
            coltitle = "white",
            bg = "#E6E6E6", 
            extent = nuts0.spdf)
plot(nuts1.spdf, col = "#B8704D50",border = "white", add=TRUE)
dotDensityLayer(spdf = nuts1.spdf, df=nuts1.df,var="pop2008",
                type = "regular", pch=20, col = "brown",
                n = 100000)