From c6ee309b2dfcc4334279c915be43952f75620ceb Mon Sep 17 00:00:00 2001
From: Martin Davis <mtnclimb@gmail.com>
Date: Wed, 22 Nov 2023 07:44:32 -0800
Subject: [PATCH] Fix DiscreteHausdorffDistance for LinearRing (#1000)

---
 .../algorithm/distance/DiscreteHausdorffDistance.h    |  8 --------
 src/algorithm/distance/DistanceToPoint.cpp            |  2 +-
 .../distance/DiscreteHausdorffDistanceTest.cpp        | 11 +++++++++++
 3 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/include/geos/algorithm/distance/DiscreteHausdorffDistance.h b/include/geos/algorithm/distance/DiscreteHausdorffDistance.h
index 5dc1dd0a65..be136edeeb 100644
--- a/include/geos/algorithm/distance/DiscreteHausdorffDistance.h
+++ b/include/geos/algorithm/distance/DiscreteHausdorffDistance.h
@@ -36,19 +36,11 @@
 #endif
 
 namespace geos {
-namespace algorithm {
-//class RayCrossingCounter;
-}
 namespace geom {
 class Geometry;
 class Coordinate;
 //class CoordinateSequence;
 }
-namespace index {
-namespace intervalrtree {
-//class SortedPackedIntervalRTree;
-}
-}
 }
 
 namespace geos {
diff --git a/src/algorithm/distance/DistanceToPoint.cpp b/src/algorithm/distance/DistanceToPoint.cpp
index 1891b63f83..b983432292 100644
--- a/src/algorithm/distance/DistanceToPoint.cpp
+++ b/src/algorithm/distance/DistanceToPoint.cpp
@@ -45,7 +45,7 @@ DistanceToPoint::computeDistance(const geom::Geometry& geom,
         return;
     }
 
-    if(geom.getGeometryTypeId() == GEOS_LINESTRING) {
+    if(geom.getGeometryTypeId() == GEOS_LINESTRING || geom.getGeometryTypeId() == GEOS_LINEARRING) {
         const LineString* ls = static_cast<const LineString*>(&geom);
         computeDistance(*ls, pt, ptDist);
     }
diff --git a/tests/unit/algorithm/distance/DiscreteHausdorffDistanceTest.cpp b/tests/unit/algorithm/distance/DiscreteHausdorffDistanceTest.cpp
index 5f21fe420b..735344cd59 100644
--- a/tests/unit/algorithm/distance/DiscreteHausdorffDistanceTest.cpp
+++ b/tests/unit/algorithm/distance/DiscreteHausdorffDistanceTest.cpp
@@ -216,5 +216,16 @@ void object::test<7>
                   DiscreteHausdorffDistance::distance(*g2, *g3));
 }
 
+// see https://github.com/libgeos/geos/issues/987
+template<>
+template<>
+void object::test<8>
+()
+{
+    runTest("LINEARRING (0 0, 0 10, 10 10, 10 0, 0 0)",
+            "LINEARRING (1 1, 1 9, 8 8, 9 1, 1 1)", 
+            2.8284271247461903);
+}
+
 } // namespace tut