mapTissot {oce} | R Documentation |
Plot ellipses at grid intersection points, as a method for indicating the distortion inherent in the projection [1].
mapTissot(grid=rep(15, 2), scale=0.2, ...)
grid |
numeric vector of length 2, specifying the increment in
longitude and latitude for the grid. Indicatrices are drawn at e.g.
longitudes |
scale |
scale factor for ellipses. This is multiplied by
|
... |
extra arguments passed to plotting functions, e.g.
|
The purpose and interpretation are outline in [1], but should also be self-explanatory.
Dan Kelley
1. Snyder, John P., 1987. Map Projections: A Working Manual. USGS Professional Paper: 1395 (available at pubs.usgs.gov/pp/1395/report.pdf).
See mapPlot
for general information on plotting maps,
including other functions.
## Not run: library(oce) data(coastlineWorld) par(mfrow=c(1,1), mar=c(2, 2, 1, 1)) p <- "+proj=aea +lat_1=10 +lat_2=60 +lon_0=-45" mapPlot(coastlineWorld, projection=p, fill="gray", longitudelim=c(-90,0), latitudelim=c(0,50)) mapTissot(c(15, 15), col='red') ## End(Not run)