OSGeo · mwtoews · Nov 20, 2021 · Oct 13, 2020 · Oct 13, 2020 · Oct 13, 2020
diff --git a/docs/images/general_ellipsoid.png b/docs/images/general_ellipsoid.png
diff --git a/docs/images/general_ellipsoid.svg b/docs/images/general_ellipsoid.svg
diff --git a/docs/source/news.rst b/docs/source/news.rst
@@ -21,6 +21,8 @@ Details about the build system unification can be found in :ref:`RFC7`.
 Updates
 -------
 
+* Docs: add new page Usage/Ellipsoids to explain the usage of ellipsoidal parameters
+
 * Added the S2 projection (`#2749 <https://github.com/OSGEO/PROJ/issues/2749>`_)
 
 * Added support for Degree Sign on input (`#2791 <https://github.com/OSGEO/PROJ/issues/2791>`_)

diff --git a/docs/source/operations/options/R.rst b/docs/source/operations/options/R.rst
@@ -1,4 +1,6 @@
 .. option:: +R=<value>
 
-    Radius of the sphere given in meters. If used in conjunction with ``+ellps``,
-    ``+R`` takes precedence.
+    Radius of the sphere, given in meters. If used in conjunction with
+    ``+ellps``, :option:`+R` takes precedence.
+
+    See :ref:`ellipsoid_size_parameters` for more information.
diff --git a/docs/source/operations/options/ellps.rst b/docs/source/operations/options/ellps.rst
@@ -1,5 +1,8 @@
 .. option:: +ellps=<value>
 
-    See :option:`proj -le` for a list of available ellipsoids.
+    The name of a built-in ellipsoid definition.
+
+    See :ref:`ellipsoids` for more information, or execute
+    :option:`proj -le` for a list of built-in ellipsoid names.
 
     *Defaults to "GRS80".*
-Original file line number
+Diff line change
@@ Expand Up @@
     Updates
     -------
+    * Docs: add new page Usage/Ellipsoids to explain the usage of ellipsoidal parameters
     * Added the S2 projection (`#2749 <https://github.com/OSGEO/PROJ/issues/2749>`_)
     * Added support for Degree Sign on input (`#2791 <https://github.com/OSGEO/PROJ/issues/2791>`_)
@@ Expand Down @@