gmt-fork/doc/rst/source/explain_distcalc_full.rst_

.. _-distcalc_full:

**-je**\|\ **f**\|\ **g**
    Determine how spherical distances are calculated in modules that support this.
    By default (**-jg**), we perform great circle distance calculations and parameters such
    as distance increments or radii will be compared against calculated great
    circle distances. To simplify and speed up calculations you can select Flat
    Earth mode (**-jf**) which gives an approximate but faster result.  Alternatively,
    you can select ellipsoidal (**-je**; or geodesic) mode for the highest precision
    (and slowest calculation time).  All spherical distance calculations depend on
    the current ellipsoid (:term:`PROJ_ELLIPSOID`), the definition of
    the mean radius (:term:`PROJ_MEAN_RADIUS`), and the specification
    of latitude type (:term:`PROJ_AUX_LATITUDE`).  Geodesic distance
    calculations is also controlled by method (:term:`PROJ_GEODESIC`).