Add documentation for datatypes and functions related to internal lists in PROJ.4.

[skip ci]

2 files changed, 147 insertions, 0 deletions

diff --git a/docs/source/development/reference/datatypes.rst b/docs/source/development/reference/datatypes.rst
index 7e314dce..85cedea6 100644
--- a/docs/source/development/reference/datatypes.rst
+++ b/docs/source/development/reference/datatypes.rst
@@ -749,6 +749,110 @@ Projection derivatives
 
             Meridian convergence calculated analytically.
 
+List structures
+-------------------------------------------------------------------------------
+
+.. c:type:: PJ_OPERATIONS
+
+    Description a PROJ.4 operation
+
+    .. code-block:: C
+
+        struct PJ_OPERATIONS {
+            char    *id;                 /* operation keyword */
+            PJ *(*proj)(PJ *);           /* operation  entry point */
+            char    * const *descr;      /* description text */
+        };
+
+    .. c:member:: char *id
+
+        Operation keyword.
+
+    .. c:member:: PJ *(*op)(PJ *)
+
+        Operation entry point.
+
+    .. c:member:: char * const *
+
+        Description of operation.
+
+
+.. c:type:: PJ_ELLPS
+
+    Description of ellipsoids defined in PROJ.4
+
+    .. code-block:: C
+
+        struct PJ_ELLPS {
+            char    *id;
+            char    *major;
+            char    *ell;
+            char    *name;
+        };
+
+    .. c:member:: char *id
+
+        Keyword name of the ellipsoid.
+
+    .. c:member:: char *major
+
+        Semi-major axis of the ellipsoid, or radius in case of a sphere.
+
+    .. c:member:: char *ell
+
+        Elliptical parameter, e.g. `rf=298.257` or `b=6356772.2`.
+
+    .. c:member:: char *name
+
+        Name of the ellipsoid
+
+.. c:type:: PJ_UNITS
+
+    Distance units defined in PROJ.4.
+
+    .. code-block:: C
+
+        struct PJ_UNITS {
+            char    *id;           /* units keyword */
+            char    *to_meter;     /* multiply by value to get meters */
+            char    *name;         /* comments */
+            double   factor;       /* to_meter factor in actual numbers */
+        };
+
+    .. c:member:: char *id
+
+        Keyword for the unit.
+
+    .. c:member:: char *to_meter
+
+        Text representation of the factor that converts a given unit to meters
+
+    .. c:member:: char *name
+
+        Name of the unit.
+
+    .. c:member:: double factor
+
+        Conversion factor that converts the unit to meters.
+
+.. c:type:: PJ_PRIME_MERIDIANS
+
+    Prime meridians defined in PROJ.4.
+
+    .. code-block:: C
+
+        struct PJ_PRIME_MERIDIANS {
+            char    *id;
+            char    *defn;
+        };
+
+    .. c:member:: char *id
+
+        Keyword for the prime meridian
+
+    .. c:member:: char *def
+
+        Offset from Greenwich in DMS format.
 
 Info structures
 -------------------------------------------------------------------------------
diff --git a/docs/source/development/reference/functions.rst b/docs/source/development/reference/functions.rst
index daefce4b..10af19d4 100644
--- a/docs/source/development/reference/functions.rst
+++ b/docs/source/development/reference/functions.rst
@@ -396,6 +396,49 @@ Info functions
     :type `initname`: const char*
     :returns: :c:type:`PJ_INIT_INFO`
 
+Lists
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+
+.. c:function::  const PJ_OPERATIONS* proj_list_operations(void)
+
+    Get a pointer to an array of all operations in PROJ.4. The last entry
+    of the returned array is a NULL-entry. The array is statically allocated
+    and does not need to be freed after use.
+
+    Print a list of all operations in PROJ.4:
+
+    .. code-block:: C
+
+        PJ_OPERATIONS *ops;
+        for (ops = proj_list_operations(); ops->id; ++ops)
+            printf("%s\n", ops->id);
+
+
+    :returns: :c:type:`PJ_OPERATIONS*`
+
+.. c:function:: const PJ_ELLPS* proj_list_ellps(void)
+
+    Get a pointer to an array of ellipsoids defined in PROJ.4. The last entry
+    of the returned array is a NULL-entry. The array is statically allocated
+    and does not need to be freed after use.
+
+    :returns: :c:type:`PJ_ELLPS*`
+
+.. c:function:: const PJ_UNITS* proj_list_units(void)
+
+    Get a pointer to an array of distance units defined in PROJ.4. The last
+    entry of the returned array is a NULL-entry. The array is statically
+    allocated and does not need to be freed after use.
+
+    :returns: :c:type:`PJ_UNITS*`
+
+.. c:function:: const PJ_PRIME_MERIDIANS* proj_list_prime_meridians(void)
+
+    Get a pointer to an array of prime meridians defined in PROJ.4. The last
+    entry of the returned array is a NULL-entry. The array is statically
+    allocated and does not need to be freed after use.
+
+    :returns: :c:type:`PJ_PRIME_MERIDIANS*`
 
 Distances
 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++