oce (version 0.9-18)

lonlat2map: Convert from longitude and latitude to x-y coordinates

Description

Convert from longitude and latitude to x-y coordinates

Usage

lonlat2map(longitude, latitude, projection="")

Arguments

longitude

a vector containing decimal longitudes, or a list containing items named longitude and latitude, in which case the indicated values are used, and next argument is ignored.

latitude

a vector containing decimal latitude (ignored if longitude is a list, as described above).

projection

optional indication of projection. This must be character string in the format used by the rgdal package; see mapPlot.)

Value

• A list containing x and y.

Details

If a projection is already being used (e.g. as set by mapPlot) then only longitude and latitude should be given, and the other arguments will be inferred by lonlat2map. This is important because otherwise, if a new projection is called for, it will ruin any additions to the existing plot.

See Also

mapLongitudeLatitudeXY is a safer alternative, if a map has already been drawn with mapPlot, because that function cannot alter an existing projection. map2lonlat is an inverse to map2lonlat.

Examples

library(oce)
## Cape Split, in the Minas Basin of the Bay of Fundy
cs <- list(longitude=-64.49657,latitude=45.33462)
xy <- lonlat2map(cs, projection="+proj=merc")
map2lonlat(xy)