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.
lonlat2map(longitude, latitude, projection = "", debug = getOption("oceDebug"))a numeric 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.
a numeric vector containing decimal latitude (ignored if
longitude is a list, as described above).
optional indication of projection. This must be character
string in the format used by the sf package;
see mapPlot().)
an integer specifying whether debugging information is
to be printed during the processing. This is a general parameter that
is used by many oce functions. Generally, setting debug=0
turns off the printing, while higher values suggest that more information
be printed. If one function calls another, it usually reduces the value of
debug first, so that a user can often obtain deeper debugging
by specifying higher debug values.
A list containing x and y.
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.
Other functions related to maps:
formatPosition(),
lonlat2utm(),
map2lonlat(),
mapArrows(),
mapAxis(),
mapContour(),
mapCoordinateSystem(),
mapDirectionField(),
mapGrid(),
mapImage(),
mapLines(),
mapLocator(),
mapLongitudeLatitudeXY(),
mapPlot(),
mapPoints(),
mapPolygon(),
mapScalebar(),
mapText(),
mapTissot(),
oceCRS(),
oceProject(),
shiftLongitude(),
usrLonLat(),
utm2lonlat()
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)
#> $longitude
#> [1] -64.49657
#>
#> $latitude
#> [1] 45.33462
#>