mapasp

From sp v1.0-15
0th

Percentile

Calculate aspect ratio for plotting geographic maps; create nice degree axis labels

Calculate aspect ratio for plotting geographic maps; create nice degree axis labels

Keywords
dplot
Usage
mapasp(data, xlim, ylim)
degreeLabelsEW(x)
degreeLabelsNS(x)
Arguments
data
object of class or extending Spatial
xlim
the xlim argument passed (or derived from bounding box)
ylim
the ylim argument passed (or derived from bounding box)
x
numeric; values at which tics and marks will be generated
Value

• mapasp is used for the aspect argument in lattice plots and spplot;

let x = dy/dx, with dy and dx the y- and x-size of the map.

let s = 1/cos((My * pi)/180) with My the y coordinate of the middle of the map (the mean of ylim)

for latlong (longlat) data, mapasp returns s * x. for other data, mapasp returns "iso".

Note

the values for x are typically obtained from axTicks

levelplot in package lattice