From: Sandro Santilli <strk@keybit.net>
Date: Wed, 29 Feb 2012 15:59:14 +0000 (+0000)
Subject: Check first point after snapping an edge to a new point (#1631)
X-Git-Tag: 2.0.0beta1~4
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=9c19f7f94011ee5013fbd7ec19a4a91556cc80d7;p=postgis

Check first point after snapping an edge to a new point (#1631)

git-svn-id: http://svn.osgeo.org/postgis/trunk@9352 b70326c6-7e19-0410-871a-916f4a2858ee
---

diff --git a/topology/sql/populate.sql.in.c b/topology/sql/populate.sql.in.c
index 3d78ec3fa..4c7ec9220 100644
--- a/topology/sql/populate.sql.in.c
+++ b/topology/sql/populate.sql.in.c
@@ -14,6 +14,7 @@
 --
 -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
+/* #define POSTGIS_TOPOLOGY_DEBUG 1 */
 
 --{
 --
@@ -713,6 +714,17 @@ BEGIN
       RAISE DEBUG 'Tolerance for snapping to point % = %', ST_AsText(prj), snaptol;
 #endif
       snapedge := ST_Snap(rec.geom, prj, snaptol);
+
+      -- Snapping currently snaps the first point below tolerance
+      -- so may possibly move first point. See ticket #1631
+      IF NOT ST_Equals(ST_StartPoint(rec.geom), ST_StartPoint(snapedge))
+      THEN
+#ifdef POSTGIS_TOPOLOGY_DEBUG
+        RAISE WARNING 'Snapping moved first edge vertex, fixing';
+#endif
+        snapedge := ST_MakeLine(ST_StartPoint(rec.geom), snapedge);
+      END IF;
+
 #ifdef POSTGIS_TOPOLOGY_DEBUG
       IF NOT ST_Contains(snapedge, prj) THEN -- or if equal ?
         RAISE WARNING 'Edge within % distance from node still does not contain the node after snapping to it with tolerance %', tolerance, snaptol;
diff --git a/topology/test/regress/topogeo_addlinestring.sql b/topology/test/regress/topogeo_addlinestring.sql
index 564e9b4e9..1b92e4fbd 100644
--- a/topology/test/regress/topogeo_addlinestring.sql
+++ b/topology/test/regress/topogeo_addlinestring.sql
@@ -126,6 +126,22 @@ SELECT check_changes();
 SELECT '#1613.2', TopoGeo_addLineString('city_data', 'LINESTRING(556250 144887, 556267 144887.07, 556310.04 144887)') ORDER BY 2;
 SELECT check_changes();
 
+-- See http://trac.osgeo.org/postgis/attachment/ticket/1631
+
+-- clean all up first
+DELETE FROM city_data.edge_data; 
+DELETE FROM city_data.node; 
+--DELETE FROM city_data.face; -- a bug forbids this (TODO: check what it is)
+
+SELECT '#1631.1', TopoGeo_addLineString('city_data',
+  'LINESTRING(556267.56295432 144887.06663814,556267.566 144888)'
+) ORDER BY 2;
+SELECT check_changes();
+SELECT '#1631.2', TopoGeo_addLineString('city_data',
+  'LINESTRING(556254.67 144886.62, 556267.66 144887.07)'
+) ORDER BY 2;
+SELECT check_changes();
+
 -- Cleanups
 DROP FUNCTION check_changes();
 SELECT DropTopology('city_data');
diff --git a/topology/test/regress/topogeo_addlinestring_expected b/topology/test/regress/topogeo_addlinestring_expected
index 0ed92a18b..e820ee739 100644
--- a/topology/test/regress/topogeo_addlinestring_expected
+++ b/topology/test/regress/topogeo_addlinestring_expected
@@ -108,4 +108,17 @@ E|51|sn46|en49
 E|52|sn49|en47
 E|53|sn48|en49
 E|54|sn49|en50
+#1631.1|55
+N|51||POINT(556267.6 144887)
+N|52||POINT(556267.6 144888)
+E|55|sn51|en52
+#1631.2|57
+#1631.2|58
+N|53||POINT(556254.6 144886.6)
+N|54||POINT(556267.6 144887)
+N|55||POINT(556267.6 144887)
+E|55|sn51|en54
+E|56|sn54|en52
+E|57|sn53|en54
+E|58|sn54|en55
 Topology 'city_data' dropped