Further map projections and geodesy

RobinsonProject: Robinson projection with PROJ's coefficient tables. WebMercator: EPSG:3857. MapUnproject: inverse projections (webmerc, merc, sinu, moll, robin). RotatedPole: geographic to rotated-pole coordinates and back (PROJ ob_tran, CF rotated_latitude_longitude). RotatedGrid: true coordinates of a regular rotated grid. NormalGravity: Somigliana normal gravity. GeoidHeight: Bruns geoid undulation from fully normalised coefficients. Identical to the Python arm morie.fn.projextra.

Usage

RobinsonProject(lon, lat, R = 6378137, lon_0 = 0)

WebMercator(lon, lat)

MapUnproject(x, y, proj, R = NULL, lon_0 = 0, k_0 = 1)

RotatedPole(lon, lat, pole_lon, pole_lat, inverse = FALSE)

RotatedGrid(rlon, rlat, pole_lon, pole_lat)

NormalGravity(lat)

GeoidHeight(lon, lat, C, S, gm = 398600441800000, a = 6378137)

Arguments

lon, lat

Degrees.

R

Sphere radius.

lon_0

Central meridian (degrees).

x, y

Projected coordinates (metres).

proj

Projection name.

k_0

Scale factor.

pole_lon, pole_lat

Rotated north pole in true coordinates.

inverse

Map rotated coordinates back to true ones.

rlon, rlat

Rotated grid axes (degrees).

C, S

Lists of coefficient vectors by degree (index n + 1, order m + 1).

gm, a

Gravitational constant times mass, and semi-major axis.

Value

Numeric vector, list, or number.

References

Snyder, J. P. (1987). Map Projections: A Working Manual. USGS Professional Paper 1395.

Snyder, J. P. (1990). The Robinson projection: a computation algorithm. Cartography and Geographic Information Systems 17, 301-305.

Heiskanen, W. A. and Moritz, H. (1967). Physical Geodesy. Freeman.

Examples

RobinsonProject(10, 50)
#> [1]  819964.6 5326895.7
MapUnproject(1113194.908, 6446275.841, "webmerc")
#> [1] 10 50
RotatedPole(10, 50, 10, 40)
#> [1] 2.544444e-14 8.000000e+01