EPSG

"Map Projections - A Working Manual" by John P. Snyder, USGS Professional Paper 1395.

2023-06-29

This is the spherical form of the projection. See coordinate operation method Lambert Azimuthal Equal Area (code 9820) for ellipsoidal form. Differences of several tens of metres result from comparison of the two methods.

See information source. R is the radius of the sphere and will normally be one of the CRS parameters. If the figure of the earth used is an ellipsoid rather than a sphere then R should be calculated as the radius of the authalic sphere using the formula for RA given in EPSG Guidance Note 7-2, section 1.2, table 3. Note however that if applying spherical formula to ellipsoidal coordinates, the authalic projection properties are not preserved.