Support importing/exporting WKT & PROJJSON of 2D axis spherical planetocentric geodetic CRS

3 files changed, 68 insertions, 13 deletions

diff --git a/src/iso19111/coordinatesystem.cpp b/src/iso19111/coordinatesystem.cpp
index 498e3035..f9db5406 100644
--- a/src/iso19111/coordinatesystem.cpp
+++ b/src/iso19111/coordinatesystem.cpp
@@ -667,6 +667,27 @@ SphericalCSNNPtr SphericalCS::create(const util::PropertyMap &properties,
 
 // ---------------------------------------------------------------------------
 
+/** \brief Instantiate a SphericalCS with 2 axis.
+ *
+ * This is an extension to ISO19111 to support (planet)-ocentric CS with
+ * geocentric latitude.
+ *
+ * @param properties See \ref general_properties.
+ * @param axis1 The first axis.
+ * @param axis2 The second axis.
+ * @return a new SphericalCS.
+ */
+SphericalCSNNPtr SphericalCS::create(const util::PropertyMap &properties,
+                                     const CoordinateSystemAxisNNPtr &axis1,
+                                     const CoordinateSystemAxisNNPtr &axis2) {
+    std::vector<CoordinateSystemAxisNNPtr> axis{axis1, axis2};
+    auto cs(SphericalCS::nn_make_shared<SphericalCS>(axis));
+    cs->setProperties(properties);
+    return cs;
+}
+
+// ---------------------------------------------------------------------------
+
 //! @cond Doxygen_Suppress
 EllipsoidalCS::~EllipsoidalCS() = default;
 //! @endcond
diff --git a/src/iso19111/crs.cpp b/src/iso19111/crs.cpp
index 7c8fcd81..6f511043 100644
--- a/src/iso19111/crs.cpp
+++ b/src/iso19111/crs.cpp
@@ -1608,7 +1608,7 @@ GeodeticCRS::velocityModel() PROJ_PURE_DEFN {
 
 // ---------------------------------------------------------------------------
 
-/** \brief Return whether the CRS is a geocentric one.
+/** \brief Return whether the CRS is a Cartesian geocentric one.
  *
  * A geocentric CRS is a geodetic CRS that has a Cartesian coordinate system
  * with three axis, whose direction is respectively
@@ -1629,6 +1629,31 @@ bool GeodeticCRS::isGeocentric() PROJ_PURE_DEFN {
 
 // ---------------------------------------------------------------------------
 
+/** \brief Return whether the CRS is a Spherical planetocentric one.
+ *
+ * A Spherical planetocentric CRS is a geodetic CRS that has a spherical
+ * (angular) coordinate system with 2 axis, which represent geocentric latitude/
+ * longitude or longitude/geocentric latitude.
+ *
+ * Such CRS are typically used in use case that apply to non-Earth bodies.
+ *
+ * @return true if the CRS is a Spherical planetocentric CRS.
+ *
+ * @since 8.2
+ */
+bool GeodeticCRS::isSphericalPlanetocentric() PROJ_PURE_DEFN {
+    const auto &cs = coordinateSystem();
+    const auto &axisList = cs->axisList();
+    return axisList.size() == 2 &&
+           dynamic_cast<cs::SphericalCS *>(cs.get()) != nullptr &&
+           ((ci_equal(axisList[0]->nameStr(), "planetocentric latitude") &&
+             ci_equal(axisList[1]->nameStr(), "planetocentric longitude")) ||
+            (ci_equal(axisList[0]->nameStr(), "planetocentric longitude") &&
+             ci_equal(axisList[1]->nameStr(), "planetocentric latitude")));
+}
+
+// ---------------------------------------------------------------------------
+
 /** \brief Instantiate a GeodeticCRS from a datum::GeodeticReferenceFrame and a
  * cs::SphericalCS.
  *
diff --git a/src/iso19111/io.cpp b/src/iso19111/io.cpp
index a1b06ae7..1373c583 100644
--- a/src/iso19111/io.cpp
+++ b/src/iso19111/io.cpp
@@ -2798,7 +2798,11 @@ WKTParser::Private::buildCS(const WKTNodeNNPtr &node, /* maybe null */
             return VerticalCS::create(csMap, axisList[0]);
         }
     } else if (ci_equal(csType, "spherical")) {
-        if (axisCount == 3) {
+        if (axisCount == 2) {
+            // Extension to ISO19111 to support (planet)-ocentric CS with
+            // geocentric latitude
+            return SphericalCS::create(csMap, axisList[0], axisList[1]);
+        } else if (axisCount == 3) {
             return SphericalCS::create(csMap, axisList[0], axisList[1],
                                        axisList[2]);
         }
@@ -5945,62 +5949,67 @@ CoordinateSystemNNPtr JSONParser::buildCS(const json &j) {
         axisList.emplace_back(buildAxis(axis));
     }
     const PropertyMap &csMap = emptyPropertyMap;
+    const auto axisCount = axisList.size();
     if (subtype == "ellipsoidal") {
-        if (axisList.size() == 2) {
+        if (axisCount == 2) {
             return EllipsoidalCS::create(csMap, axisList[0], axisList[1]);
         }
-        if (axisList.size() == 3) {
+        if (axisCount == 3) {
             return EllipsoidalCS::create(csMap, axisList[0], axisList[1],
                                          axisList[2]);
         }
         throw ParsingException("Expected 2 or 3 axis");
     }
     if (subtype == "Cartesian") {
-        if (axisList.size() == 2) {
+        if (axisCount == 2) {
             return CartesianCS::create(csMap, axisList[0], axisList[1]);
         }
-        if (axisList.size() == 3) {
+        if (axisCount == 3) {
             return CartesianCS::create(csMap, axisList[0], axisList[1],
                                        axisList[2]);
         }
         throw ParsingException("Expected 2 or 3 axis");
     }
     if (subtype == "vertical") {
-        if (axisList.size() == 1) {
+        if (axisCount == 1) {
             return VerticalCS::create(csMap, axisList[0]);
         }
         throw ParsingException("Expected 1 axis");
     }
     if (subtype == "spherical") {
-        if (axisList.size() == 3) {
+        if (axisCount == 2) {
+            // Extension to ISO19111 to support (planet)-ocentric CS with
+            // geocentric latitude
+            return SphericalCS::create(csMap, axisList[0], axisList[1]);
+        } else if (axisCount == 3) {
             return SphericalCS::create(csMap, axisList[0], axisList[1],
                                        axisList[2]);
         }
-        throw ParsingException("Expected 3 axis");
+        throw ParsingException("Expected 2 or 3 axis");
     }
     if (subtype == "ordinal") {
         return OrdinalCS::create(csMap, axisList);
     }
     if (subtype == "parametric") {
-        if (axisList.size() == 1) {
+        if (axisCount == 1) {
             return ParametricCS::create(csMap, axisList[0]);
         }
         throw ParsingException("Expected 1 axis");
     }
     if (subtype == "TemporalDateTime") {
-        if (axisList.size() == 1) {
+        if (axisCount == 1) {
             return DateTimeTemporalCS::create(csMap, axisList[0]);
         }
         throw ParsingException("Expected 1 axis");
     }
     if (subtype == "TemporalCount") {
-        if (axisList.size() == 1) {
+        if (axisCount == 1) {
             return TemporalCountCS::create(csMap, axisList[0]);
         }
         throw ParsingException("Expected 1 axis");
     }
     if (subtype == "TemporalMeasure") {
-        if (axisList.size() == 1) {
+        if (axisCount == 1) {
             return TemporalMeasureCS::create(csMap, axisList[0]);
         }
         throw ParsingException("Expected 1 axis");