lamaz.eqarea {GEOmap}

Lambert-Azimuthal Equal Area

Description

Map Projection (Lambert-Azimuthal Equal Area) for global plots.

Usage

lamaz.eqarea(phi1, lam0, phi, lam, R=6371)
lamaz.inverse(phi1, lam0, x, y, R=6371 ) 

Arguments

phi1

Central Latitude, radians

lam0

Central Longitude

phi

vector of Latitude, points for plotting, radians

lam

vector of Longitude, points for plotting , radians

R

radius of sphere

x

position on the plot

y

position on the plot

Value

x

position on the plot

y

position on the plot

Note

This is a projection routine that does not need to be set in advance. lamaz.inverse is the inverse of lamaz.eqarea.

Author(s)

Jonathan M. Lees<[e-mail]>

References

Snyder, J. P., 1987; Map Projections - A Working Manual. U.S. Geological Survey Professional Paper 1395, 383 p.

See Also

setPROJ

Examples

data(coastmap)
#########  coastmap is a GEOmap list
DEGRAD = pi/180

phicen  = -90*DEGRAD
lamcen  = 0*DEGRAD

i = 7
j1 = coastmap$STROKES$index[i]+1
j2 = j1+ coastmap$STROKES$num[i]-1
lat = coastmap$POINTS$lat[j1:j2]*DEGRAD
lon = coastmap$POINTS$lon[j1:j2]*DEGRAD

 xy = lamaz.eqarea(phicen, lamcen,lat, lon)

plot(xy, asp=1, type='n')


 polygon(xy, col=grey(.8))

title("Antarctica")