Merge pull request #60767 from qgis/backport-60759-to-release-3_42

[Backport release-3_42] Always fallback to default coordinate operations when bounding box transfrom fails
qgis · Feb 26, 2025 · 01369ae · 01369ae
2 parents 9d6b3b4 + 60fd522
commit 01369ae
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Showing 2 changed files with 66 additions and 3 deletions.
diff --git a/src/core/proj/qgscoordinatetransform.cpp b/src/core/proj/qgscoordinatetransform.cpp
@@ -676,9 +676,27 @@ QgsRectangle QgsCoordinateTransform::transformBoundingBox( const QgsRectangle &r
   proj_errno_reset( projData );
   // proj documentation recommends 21 points for densification
   constexpr int DENSIFY_POINTS = 21;
-  const int projResult = proj_trans_bounds( projContext, projData, ( direction == Qgis::TransformDirection::Forward && !d->mIsReversed ) || ( direction == Qgis::TransformDirection::Reverse && d->mIsReversed ) ? PJ_FWD : PJ_INV,
-                         xMin, yMin, xMax, yMax,
-                         &transXMin, &transYMin, &transXMax, &transYMax, DENSIFY_POINTS );
+  int projResult = proj_trans_bounds( projContext, projData, ( direction == Qgis::TransformDirection::Forward && !d->mIsReversed ) || ( direction == Qgis::TransformDirection::Reverse && d->mIsReversed ) ? PJ_FWD : PJ_INV,
+                                      xMin, yMin, xMax, yMax,
+                                      &transXMin, &transYMin, &transXMax, &transYMax, DENSIFY_POINTS );
+
+  if ( ( projResult != 1
+         || !std::isfinite( transXMin )
+         || !std::isfinite( transXMax )
+         || !std::isfinite( transYMin )
+         || !std::isfinite( transYMax ) )
+       && ( d->mAvailableOpCount > 1 || d->mAvailableOpCount == -1 ) // only use fallbacks if more than one operation is possible -- otherwise we've already tried it and it failed
+     )
+  {
+    // fail #1 -- try with getting proj to auto-pick an appropriate coordinate operation for the points
+    if ( PJ *transform = d->threadLocalFallbackProjData() )
+    {
+      projResult = proj_trans_bounds( projContext, transform, ( direction == Qgis::TransformDirection::Forward && !d->mIsReversed ) || ( direction == Qgis::TransformDirection::Reverse && d->mIsReversed ) ? PJ_FWD : PJ_INV,
+                                      xMin, yMin, xMax, yMax,
+                                      &transXMin, &transYMin, &transXMax, &transYMax, DENSIFY_POINTS );
+    }
+  }
+
   if ( projResult != 1
        || !std::isfinite( transXMin )
        || !std::isfinite( transXMax )

diff --git a/tests/src/python/test_qgscoordinatetransform.py b/tests/src/python/test_qgscoordinatetransform.py
@@ -127,6 +127,51 @@ def testTransformQgsRectangle_Regression17600(self):
             myTransformedExtentReverse.yMinimum(), myExtent.yMinimum()
         )
 
+    def test_transform_bounding_box_grid(self):
+        """
+        This test assumes the ca_nrc_NA83SCRS.tif grid is available on the system!
+        """
+        transform = QgsCoordinateTransform(
+            QgsCoordinateReferenceSystem("EPSG:4269"),
+            QgsCoordinateReferenceSystem("EPSG:3857"),
+            QgsCoordinateTransformContext(),
+        )
+        res = transform.transformBoundingBox(
+            QgsRectangle(
+                -123.65020876249999,
+                45.987175336410544,
+                -101.22289073749998,
+                62.961980263589439,
+            )
+        )
+        self.assertAlmostEqual(res.xMinimum(), -13764678, -2)
+        self.assertAlmostEqual(res.yMinimum(), 5778294, -2)
+        self.assertAlmostEqual(res.xMaximum(), -11268080, -2)
+        self.assertAlmostEqual(res.yMaximum(), 9090934, -2)
+
+        transform = QgsCoordinateTransform(
+            QgsCoordinateReferenceSystem("EPSG:4269"),
+            QgsCoordinateReferenceSystem("EPSG:3857"),
+            QgsCoordinateTransformContext(),
+        )
+        # force use of grid shift operation. This will fail as the source rect is outside of the grid bounds, but we should silently
+        # fall back to the non-grid operation
+        transform.setCoordinateOperation(
+            "+proj=pipeline +step +proj=unitconvert +xy_in=deg +xy_out=rad +step +proj=hgridshift +grids=ca_nrc_NA83SCRS.tif +step +proj=webmerc +lat_0=0 +lon_0=0 +x_0=0 +y_0=0 +ellps=WGS84"
+        )
+        res = transform.transformBoundingBox(
+            QgsRectangle(
+                -123.65020876249999,
+                45.987175336410544,
+                -101.22289073749998,
+                62.961980263589439,
+            )
+        )
+        self.assertAlmostEqual(res.xMinimum(), -13764678, -2)
+        self.assertAlmostEqual(res.yMinimum(), 5778294, -2)
+        self.assertAlmostEqual(res.xMaximum(), -11268080, -2)
+        self.assertAlmostEqual(res.yMaximum(), 9090934, -2)
+
     def testContextProj6(self):
         """
         Various tests to ensure that datum transforms are correctly set respecting context