Build a regular grid gGraph

The function makeGrid builds a gGraph using a regular grid for a given area. If no area is specified, currently plotted area is used. Note that such grid is only valid for small scales, for cases in which curvature of the surface of the earth can be neglected.

Usage

makeGrid(
  size = NULL,
  n.lon = NULL,
  n.lat = NULL,
  lon.range = NULL,
  lat.range = NULL
)

Arguments

size

an integer giving the approximate number of nodes of the grid. The function will attempt to make a square grid of (approximately) this size.

n.lon

the number of longitude coordinates of the grid (i.e., width of the grid, in number of cells)

n.lat

the number of latitude coordinates of the grid (i.e., height of the grid, in number of cells)

lon.range, lat.range

vectors of length two giving the range covered by the grid, in longitude and latitude, respectively.

Value

A gGraph object.

Examples

## zoom in to a smaller area
plot(worldgraph.10k)

geo.zoomin(c(-10, 0, 50, 54))



## make a new gGraph
newGraph <- makeGrid(1e3)
newGraph <- findLand(newGraph)
newGraph@meta$colors <- data.frame(
  habitat = c("sea", "land"),
  color = c("blue", "green")
)


## plot the new gGraph
plot(newGraph, reset = TRUE, edge = TRUE)