# lamaz.eqarea: Lambert-Azimuthal Equal Area In GEOmap: Topographic and Geologic Mapping

## Description

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

## Usage

 ```1 2``` ```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<[email protected]>

## References

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

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21``` ```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") ```