The arc length calculation for the wgs84 ellipsoid at a latitude uses a taylor series to obtain the value of the elliptic integral.

\[arclat = \int_{0}^{lat}\sqrt{a^2 \cdot cos(lat)^2+b^2 \cdot sin(lat)^2}\ dlat\]

The integral of the radius taylor series gives an arc length taylor series This returns the distance from the equator to a given latitude This is accurate to within floating point error.


This needs to be a taylor series to avoid the elliptic integral


lat (numpy.ndarray, xarray.DataArray) – 2-dimensional dataset, of orthographic latitude coordinates


gradients (list of numpy.ndarray, list of xarray.DataArray) – latitudinal arc from equator calculated using th WGS84 geoid.

See also

Related NCL Functions: grad_latlon_cfd, gradsf, gradsg