Module geoids

Geoid models and geoid height interpolations.

Classes GeoidG2012B, GeoidKarney and GeoidPGM to interpolate the height of various geoids at LatLon locations or separate lat-/longitudes using different interpolation methods and geoid model files.

GeoidKarney is a transcoding of Charles Karney's C++ class Geoid to pure Python. The GeoidG2012B and GeoidPGM interpolators both depend on scipy and numpy and require those packages to be installed.

In addition, each geoid interpolator needs grid knots (down)loaded from a geoid model file, specific to the interpolator, more details below and in the documentation of the interpolator class. For each interpolator, there are several interpolation choices, like linear, cubic, etc.

Typical usage

1. Choose one of the interpolator classes GeoidG2012B, GeoidKarney or GeoidPGM and download a geoid model file, containing locations with known heights also referred to as the grid knots. See the documentation of the interpolator class for references to available grid models.

   >>> from pygeodesy import GeoidG2012B # or -Karney or -PGM as GeoidXyz

2. Instantiate an interpolator with the geoid model file and use keyword arguments to select different interpolation options

   >>> ginterpolator = GeoidXyz(geoid_model_file, **options)

3. Get the interpolated geoid height of other LatLon location(s) with

   >>> ll = LatLon(1, 2, ...)

   >>> h = ginterpolator(ll)

   or

   >>> h0, h1, h2, ... = ginterpolator(ll0, ll1, ll2, ...)

   or a list, tuple, generator, etc. of LatLons

   >>> hs = ginterpolator(lls)

4. For separate lat- and longitudes invoke the .height method as

   >>> h = ginterpolator.height(lat, lon)

   or as 2 lists, 2 tuples, etc.

   >>> hs = ginterpolator.height(lats, lons)

5. An example is in issue #64, courtesy of SBFRF.