geo (version 1.4-3)

Proj: Performs Mercator or Lambert projection of data.

Description

Performs Mercator, Lambert or no projection of data, as a default it will perform the projection used in current plot.

Usage

Proj(a, b = 0, scale = getOption("geopar")$scale, b0 = getOption("geopar")$b0, b1 = getOption("geopar")$b1, l1 = getOption("geopar")$l1, projection = getOption("geopar")$projection, col.names = c("lon", "lat"))

Arguments

a,b

The input data to be projected, may be given as two vectors or as list attributes, \$lat and \$lon (\$x and \$y if projection = none).

scale

The scale used for the projection, (m, km or miles). Default is the scale defined in geopar (the scale defined when the plot is initialized).

b0

if projection = mercator b0 is the center of the mercator projection. If projection = "Lambert" b0 and b1 are lattitudes defining the Lambert projection. Default are the b0 and b1 defined in geopar.

b1

Second defining latitute for Lambert projection

l1

The longitude defining the Lambert projection, default is the l1 defined in geopar.

projection

The projection of the data, legal projections are "Mercator", "Lambert" and "none".

col.names

This has to be set to the default value of c("lon", "lat"), otherwise projection will be set to "none".

Value

The function returns a list containing if projection = "none" x and y, if projection is "Mercator" or "Lambert" it includes the projection (\$projection), the scale (\$scale), \$lat and \$lon and \$x and \$y (the distance in \$scale from point (0,0) in spherical coordinates.

See Also

invProj, geopar, geoplot.

Examples

# For an example of use for this function see i.e. init() where
  # it is called:
## Not run: 
#   xgr <- Proj(lat, lon, scale, b0, b1, l1, projection)
# ## End(Not run)