world {fields}R Documentation

Plot of the world

Description

Plots quickly, medium resolution outlines of large land masses and bodies of water.

Usage

world(ylim = c(-90, 90), xlim = NULL, add = FALSE, asp = 1,
                 xlab = "", ylab = "", xaxt = "n", yaxt = "n", eps =
                 0.1, col=1,shift = FALSE, 
                 fill=FALSE, col.water="white", col.land="darkgrey",alpha=NA, ...)
world.land( col.water = "white", col.land = "darkgrey",alpha=NA, ...)
world.color(obj,xlim= c(-180,180), ylim=c(-90,90), 
             col.water="white",col.land="darkgrey", ... )
in.land.grid( grid.list)

Arguments

alpha

Color transparency of land fill and outlines.

ylim

range of latitudes

xlim

range of longitudes

add

logical; if true will add the world map to current plot.

asp

aspect ratio used if add is false, see plot.default .

xlab,ylab

labels for x- and y-axis; empty by default.

xaxt,yaxt

axis type for x- and y-axis; empty by default.

eps

Tolerance to decide when to insert line break about 0 if map is to be shifted. (leave this at .1)

shift

If TRUE shifts to be centered on the Dateline and longitude runs from 0 to 360. If FALSE centers on Prime Meridian and longitude runs from -180 to 180.

col

Color for map lines when fill is FALSE.

fill

If FALSE draws land outlines. If TRUE fills in land and water with different colors.

col.land

Color for land filling.

col.water

Color for water filling.

obj

The data set of coast lines: world.dat

...

If the land is not filled these are graphical arguments that are passed to the lines (and plot if add is false) function that draws the outline.

If fill is TRUE then these arguments are passed to the polygon function that does the filling.

grid.list

Grid list in longitude latitude specifying rectangular grid

Details

Both functions use the FIELDS dataset world.dat for the coordinates. See the longstanding maps package for similar functionality The main advantage of these functions is that they are fast and easy to modify. The shift option to center over the dateline is useful because often plots of oceanic and atmospheric information center the map this way.

The function world.color can be used separately but is also called by world with fill being TRUE. When used alone it will just add the colored landmasses and water to an existing plot. It is easy to modify just to add the land masses and use the existing back ground color as water. Unfortunately world.color will not work when shift is TRUE. Use the maps package to accomplish this. Howevr, the current code could be modified if you need this option. Thanks to Steve McIntyre for suggesting and testing the fill option.

The function world.land adds to an existing plot a polygon fill of the land masses the water in this case is just the lakes not the ocean. Used with transparency this provides a clearer reference than just outlines.

in.land.grid Takes the grid information in the form of a grid list and returns a logical image matrix. TRUE means that the grid point is not in an ocean or a lake. For very large grids (500X1000) this make take a minute or so.

See Also

US, in.poly, in.poly.grid

Examples


world()
# add the US
US( add=TRUE,col="blue")


world( fill=TRUE) # land filled in dark grey 


## Western Europe (*which* big islands are missing?)
## with a coordinate grid:

world(xlim=c(-10,18),ylim=c(36,60), 
    xaxt = "s", yaxt = "s", fill=TRUE, col.land="darkgreen")

box() # add back in the box that was obscured by the ocean fill.

# add back in outline of land.
world( add=TRUE,lwd=1.5, col="green")

grid()

grid.list<- list( x= seq(-160,-60,,200), y= seq( 25, 55,,100))
look<- in.land.grid( grid.list)

world()
# mask for land in grid
image( grid.list$x, grid.list$y, look, add=TRUE)



[Package fields version 6.6.3 Index]