[geos-commits] [SCM] GEOS branch main updated. cc1d2bc2d31a4056b38dc829c0e1a9c0320888c9

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- Log -----------------------------------------------------------------
commit cc1d2bc2d31a4056b38dc829c0e1a9c0320888c9
Author: Daniel Baston <dbaston at gmail.com>
Date:   Mon Sep 21 12:42:23 2026 -0400

    GEOSGridIntersectionFractions: Set cells outside geometry bounding box to zero (#1532)

diff --git a/include/geos/operation/grid/Matrix.h b/include/geos/operation/grid/Matrix.h
index 67d49d9cc..1d1a1bccd 100644
--- a/include/geos/operation/grid/Matrix.h
+++ b/include/geos/operation/grid/Matrix.h
@@ -141,6 +141,10 @@ class Matrix
         return m_data.get() + m_rows * m_cols;
     }
 
+    void fill(const T& val) {
+        std::fill(m_data.get(), m_data.get() + m_rows * m_cols, val);
+    }
+
 #ifdef MATRIX_CHECK_BOUNDS
     void check(size_t row, size_t col) const
     {
diff --git a/src/operation/grid/GridIntersection.cpp b/src/operation/grid/GridIntersection.cpp
index 7c4815b75..c60c3aaec 100644
--- a/src/operation/grid/GridIntersection.cpp
+++ b/src/operation/grid/GridIntersection.cpp
@@ -60,6 +60,31 @@ get_cell(Matrix<std::unique_ptr<Cell>>& cells, const Grid<infinite_extent>& ex,
     return cells(row, col).get();
 }
 
+static Grid<infinite_extent>
+getSubgrid(const Envelope& box, const Grid<infinite_extent>& geometry_grid)
+{
+    Envelope cropped_ring_extent = geometry_grid.getExtent().intersection(box);
+    return geometry_grid.shrinkToFit(cropped_ring_extent);
+}
+
+static Grid<infinite_extent>
+getSubgrid(const Geometry& ls, const Grid<infinite_extent>& geometry_grid)
+{
+    return getSubgrid(*ls.getEnvelopeInternal(), geometry_grid);
+}
+
+
+template<typename T>
+static void
+initialize(const T& geom, const Grid<infinite_extent> geom_grid, Matrix<float>* cov)
+{
+    const auto subgrid = getSubgrid(geom, geom_grid);
+
+    if (subgrid.getNumRows() < geom_grid.getNumRows() || subgrid.getNumCols() < geom_grid.getNumCols()) {
+        cov->fill(0);
+    }
+}
+
 Envelope
 GridIntersection::processingRegion(const Envelope& raster_extent, const Geometry& g)
 {
@@ -96,6 +121,10 @@ GridIntersection::GridIntersection(const Grid<bounded_extent>& raster_grid, cons
     }
 
     if (!m_geometry_grid.isEmpty()) {
+        if (cov) {
+            initialize(g, m_geometry_grid, cov.get());
+        }
+
         process(g);
     }
 }
@@ -107,6 +136,10 @@ GridIntersection::GridIntersection(const Grid<bounded_extent>& raster_grid, cons
   , m_areal{ false }
 {
     if (!m_geometry_grid.isEmpty()) {
+        if (cov) {
+            initialize(box, m_geometry_grid, cov.get());
+        }
+
         processRectangularRing(box, true);
     }
 }
@@ -140,19 +173,6 @@ GridIntersection::process(const Geometry& g)
     }
 }
 
-static Grid<infinite_extent>
-get_box_grid(const Envelope& box, const Grid<infinite_extent>& geometry_grid)
-{
-    Envelope cropped_ring_extent = geometry_grid.getExtent().intersection(box);
-    return geometry_grid.shrinkToFit(cropped_ring_extent);
-}
-
-static Grid<infinite_extent>
-get_ring_grid(const Geometry& ls, const Grid<infinite_extent>& geometry_grid)
-{
-    return get_box_grid(*ls.getEnvelopeInternal(), geometry_grid);
-}
-
 void
 GridIntersection::processRectangularRing(const Envelope& box, bool exterior_ring)
 {
@@ -160,7 +180,7 @@ GridIntersection::processRectangularRing(const Envelope& box, bool exterior_ring
         return;
     }
 
-    auto ring_grid = get_box_grid(box, m_geometry_grid);
+    auto ring_grid = getSubgrid(box, m_geometry_grid);
 
     auto row_min = ring_grid.getRow(box.getMaxY());
     auto row_max = ring_grid.getRow(box.getMinY());
@@ -406,7 +426,7 @@ GridIntersection::processLine(const LineString& ls, bool exterior_ring)
         }
     }
 
-    Grid<infinite_extent> ring_grid = get_ring_grid(ls, m_geometry_grid);
+    Grid<infinite_extent> ring_grid = getSubgrid(ls, m_geometry_grid);
 
     size_t rows = ring_grid.getNumRows();
     size_t cols = ring_grid.getNumCols();
diff --git a/tests/unit/capi/GEOSGridIntersectionFractionsTest.cpp b/tests/unit/capi/GEOSGridIntersectionFractionsTest.cpp
index 5dacbf175..59d0c9eaa 100644
--- a/tests/unit/capi/GEOSGridIntersectionFractionsTest.cpp
+++ b/tests/unit/capi/GEOSGridIntersectionFractionsTest.cpp
@@ -64,4 +64,31 @@ void object::test<3>()
     ensure_equals(result, 0);
 }
 
+template<>
+template<>
+void object::test<4>()
+{
+    set_test_name("values outside the geometry bounding box are set to zero");
+
+    input_ = fromWKT("POLYGON ((0.5 0.5, 2.5 0.5, 2.5 2.5, 0.5 2.5, 0.5 0.5))");
+
+    const unsigned nx = 5;
+    const unsigned ny = 5;
+    const float init_value = 99999;
+
+    std::vector<float> result_vec(nx * ny, init_value);
+    int result = GEOSGridIntersectionFractions(input_, 0, 0, nx, ny, nx, ny, result_vec.data());
+    ensure_equals(result, 1);
+
+    std::vector<float> expected = {
+        0,      0,    0, 0, 0,
+        0,      0,    0, 0, 0,
+        0.25, 0.5, 0.25, 0, 0,
+        0.5,  1.0,  0.5, 0, 0,
+        0.25, 0.5, 0.25, 0, 0
+    };
+
+    ensure(result_vec == expected);
+}
+
 }

-----------------------------------------------------------------------

Summary of changes:
 include/geos/operation/grid/Matrix.h               |  4 ++
 src/operation/grid/GridIntersection.cpp            | 50 +++++++++++++++-------
 .../capi/GEOSGridIntersectionFractionsTest.cpp     | 27 ++++++++++++
 3 files changed, 66 insertions(+), 15 deletions(-)


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