oce (version 0.9-20)

map2lonlat: Convert X and Y to Longitude and Latitude

Description

Convert from x-y coordinates to longitude and latitude. This is normally called internally within oce; see ‘Bugs’.

Usage

map2lonlat(x, y, init = c(0, 0))

Arguments

x

vector containing the x component of points in the projected space, or a list containing items named x and y, in which case the next argument is ignored.

y

vector containing the y coordinate of points in the projected space (ignored if x is a list, as described above).

init

vector containing the initial guesses for longitude and latitude, presently ignored.

Value

A list containing longitude and latitude, with NA values indicating points that are off the globe as displayed.

Bugs

oce uses project in the \href{https://CRAN.R-project.org/package=#1}{\pkg{#1}}rgdalrgdal package to handle projections. Only those projections that have inverses are permitted within oce, and even those can sometimes yield errors, owing to limitations in \href{https://CRAN.R-project.org/package=#1}{\pkg{#1}}rgdalrgdal.

Details

A projection must already have been set up, by a call to mapPlot or lonlat2map. It should be noted that not all projections are handled well; see ‘Bugs’.

See Also

lonlat2map does the inverse operation.

A map must first have been created with mapPlot.

Other functions related to maps: lonlat2map, lonlat2utm, mapArrows, mapAxis, mapContour, mapDirectionField, mapGrid, mapImage, mapLines, mapLocator, mapLongitudeLatitudeXY, mapPlot, mapPoints, mapPolygon, mapScalebar, mapText, mapTissot, oceCRS, shiftLongitude, utm2lonlat

Examples

## Not run: 
# 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)
# ## End(Not run)