Add proj_normalize_for_visualization()

Fixes #1301

This function takes the output PJ from proj_create_crs_to_crs(),
and add (or undo) the needed axis swap operations so that the
object returned by proj_normalize_for_visualization() has the usual
GIS axis order.
In this implementation, this does something only if the coordinate
system of the source or target CRS, geographic or projected, has
NORTH, EAST ordering.
CompoundCRS wrapping those objects are also handled.

1 files changed, 40 insertions, 0 deletions

diff --git a/src/iso19111/coordinateoperation.cpp b/src/iso19111/coordinateoperation.cpp
index 1abb74b3..58e97272 100644
--- a/src/iso19111/coordinateoperation.cpp
+++ b/src/iso19111/coordinateoperation.cpp
@@ -765,6 +765,46 @@ void CoordinateOperation::setProperties(
 
 // ---------------------------------------------------------------------------
 
+/** \brief Return a variation of the current coordinate operation whose axis
+ * order is the one expected for visualization purposes.
+ */
+CoordinateOperationNNPtr
+CoordinateOperation::normalizeForVisualization() const {
+    auto l_sourceCRS = sourceCRS();
+    auto l_targetCRS = targetCRS();
+    if (!l_sourceCRS || !l_targetCRS) {
+        throw util::UnsupportedOperationException(
+            "Cannot retrieve source or target CRS");
+    }
+    const bool swapSource =
+        l_sourceCRS->mustAxisOrderBeSwitchedForVisualization();
+    const bool swapTarget =
+        l_targetCRS->mustAxisOrderBeSwitchedForVisualization();
+    auto l_this = NN_NO_CHECK(std::dynamic_pointer_cast<CoordinateOperation>(
+        shared_from_this().as_nullable()));
+    if (!swapSource && !swapTarget) {
+        return l_this;
+    }
+    std::vector<CoordinateOperationNNPtr> subOps;
+    if (swapSource) {
+        auto op = Conversion::createAxisOrderReversal(false);
+        op->setCRSs(l_sourceCRS->normalizeForVisualization(),
+                    NN_NO_CHECK(l_sourceCRS), nullptr);
+        subOps.emplace_back(op);
+    }
+    subOps.emplace_back(l_this);
+    if (swapTarget) {
+        auto op = Conversion::createAxisOrderReversal(false);
+        op->setCRSs(NN_NO_CHECK(l_targetCRS),
+                    l_targetCRS->normalizeForVisualization(), nullptr);
+        subOps.emplace_back(op);
+    }
+    return util::nn_static_pointer_cast<CoordinateOperation>(
+        ConcatenatedOperation::createComputeMetadata(subOps, true));
+}
+
+// ---------------------------------------------------------------------------
+
 //! @cond Doxygen_Suppress
 struct OperationMethod::Private {
     util::optional<std::string> formula_{};