plot-gGraph: Plot a gGraph object.
In thibautjombart/geograph: Walking through the geographic space using graphs

plot-gGraph

R Documentation

Plot a gGraph object.

Description

Various functions to plot a gGraph object: plot opens a device and plot the object, while points plots the object on the existing device. plotEdges only plots the edges of the graph: it can be called directly, or via arguments passed to plot and points.

Arguments

`x`	a gGraph object.
`shape`	a shapefile used as background to the object. Must be of the class `SpatialPolygonsDataFrame` (see `readShapePoly` in maptools package to import such data from a GIS shapefile). Alternatively, a character string indicating one shapefile released with geoGraph.
`psize`	a numeric giving the size of points.
`pch`	a numeric or a character indicating the type of point.
`col`	a character string indicating the color to be used.
`edges`	a logical indicating if edges should be plotted (TRUE) or not (FALSE).
`reset`	a logical indicating if plotting parameters should be reset (TRUE) or not (FALSE).
`bg.col`	a character string indicating the color of the polygons of the shapefile used as background.
`border.col`	a character string indicating the color of the polygon borders.
`lwd`	a numeric indicating the width of line (used for edges).
`useCosts`	a logical indicating if edge width should be inversely proportionnal to edge cost (TRUE) or not (FALSE).
`maxLwd`	a numeric indicating the maximum edge width (corresponding to the maximum weight).
`col.rules`	a data.frame with two named columns, the first one giving values of a node attribute, and the second one stating colors to be used for each value. If not provided, this is seeked from the `@meta\$color` slot of the object.
`sticky.points`	a logical indicating if added points should be kept when replotting (TRUE), or not (FALSE). In any case, `reset=TRUE` will prevent points to be redrawn.
`lty`	the type of line (for the edges).
`pcol`	a character indicating the color to be used for points.
`sticky.edges`	a logical indicating whether added edges should be kept when replotting (TRUE), or not (FALSE, default). In any case, `reset=TRUE` will prevent points to be redrawn.
`...`	further arguments passed to the generic methods (plot, points, and segments, respectively).

Details

Plotting of a gGraph object stores some parameters in R; see details for more information.

To be able to zoom in and out, or slide the window, previous plotting information are stored in a particular environment (.geoGraphEnv), which is created when loading geoGraph. Users should not have to interact directly with objects in this environment.

The resulting plotting behaviour is that when plotting a gGraph object, last plotting parameters are re-used. To override this behaviour, specify reset=TRUE as argument to plot.

Examples



## just the background
plot(worldgraph.10k, reset = TRUE, type = "n")

## basic plot
plot(worldgraph.10k)

## zooming and adding edges
geo.zoomin(list(x = c(90, 150), y = c(0, -50)))
plot(worldgraph.10k, edges = TRUE)


## display edges differently
plotEdges(worldgraph.10k, col = "red", lwd = 2)


## replot points with different color
points(worldgraph.10k, col = "orange")

## mask points in the sea
inSea <- unlist(getNodesAttr(worldgraph.10k, attr.name = "habitat")) == "sea"
head(inSea)
points(worldgraph.10k[inSea], col = "white", sticky = TRUE) # this will stay

## but better, only draw those on land, and use a fancy setup
par(bg = "blue")
plot(worldgraph.10k[!inSea], bg.col = "darkgreen", col = "purple", edges = TRUE)

thibautjombart/geograph documentation built on April 13, 2025, 9:39 a.m.