geom_polygon {ggplot2}R Documentation

geom_polygon

Description

Polygon, a filled path

Usage

geom_polygon(mapping=NULL, data=NULL, stat="identity", position="identity", ...)

Arguments

mapping mapping between variables and aesthetics generated by aes
data dataset used in this layer, if not specified uses plot dataset
stat statistic used by this layer
position position adjustment used by this layer
... ignored

Details

This page describes geom_polygon, see layer and qplot for how to create a complete plot from individual components.

Value

A layer

Aesthetics

The following aesthetics can be used with geom_polygon. Aesthetics are mapped to variables in the data with the aes function: geom\_polygon(\code{aes}(x = var))

Author(s)

Hadley Wickham, http://had.co.nz/

See Also

Examples

## Not run: 
# When using geom_polygon, you will typically need two data frames:
# one contains the coordinates of each polygon (positions),  and the
# other the values associated with each polygon (values).  An id
# variable links the two together

ids <- factor(c("1.1", "2.1", "1.2", "2.2", "1.3", "2.3"))

values <- data.frame(
  id = ids, 
  value = c(3, 3.1, 3.1, 3.2, 3.15, 3.5)
)

positions <- data.frame(
  id = rep(ids, each = 4),
  x = c(2, 1, 1.1, 2.2, 1, 0, 0.3, 1.1, 2.2, 1.1, 1.2, 2.5, 1.1, 0.3, 
  0.5, 1.2, 2.5, 1.2, 1.3, 2.7, 1.2, 0.5, 0.6, 1.3),
  y = c(-0.5, 0, 1, 0.5, 0, 0.5, 1.5, 1, 0.5, 1, 2.1, 1.7, 1, 1.5, 
  2.2, 2.1, 1.7, 2.1, 3.2, 2.8, 2.1, 2.2, 3.3, 3.2)
)

# Currently we need to manually merge the two together
datapoly <- merge(values, positions, by=c("id"))

(p <- ggplot(datapoly, aes(x=x, y=y)) + geom_polygon(aes(fill=value, group=id)))

# Which seems like a lot of work, but then it's easy to add on 
# other features in this coordinate system, e.g.:

stream <- data.frame(
  x = cumsum(runif(50, max = 0.1)), 
  y = cumsum(runif(50,max = 0.1))
)

p + geom_line(data = stream, colour="grey30", size = 5)

# And if the positions are in longitude and latitude, you can use
# coord_map to produce different map projections.
## End(Not run)

[Package ggplot2 version 0.8.2 Index]