From: Sandro Santilli <strk@keybit.net>
Date: Fri, 23 Mar 2012 22:54:10 +0000 (+0000)
Subject: Do not abuse ST_Snap for tweaking edge endpoints (#1706)
X-Git-Tag: 2.0.0rc1~31
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=72d9f2d9387e23a3116ba40184ef97295d5da48d;p=postgis

Do not abuse ST_Snap for tweaking edge endpoints (#1706)

git-svn-id: http://svn.osgeo.org/postgis/trunk@9540 b70326c6-7e19-0410-871a-916f4a2858ee
---

diff --git a/topology/sql/populate.sql.in.c b/topology/sql/populate.sql.in.c
index 4cdfb8b8f..cdae2ed27 100644
--- a/topology/sql/populate.sql.in.c
+++ b/topology/sql/populate.sql.in.c
@@ -792,6 +792,7 @@ CREATE OR REPLACE FUNCTION topology.TopoGeo_addLinestring(atopology varchar, ali
 $$
 DECLARE
   rec RECORD;
+  rec2 RECORD;
   sql TEXT;
   set1 GEOMETRY;
   set2 GEOMETRY;
@@ -926,26 +927,29 @@ BEGIN
     RAISE DEBUG ' End Node: %', end_node;
 #endif
 
-    -- Added endpoints may have drifted due to tol, so
+    -- Added endpoints may have drifted due to tolerance, so
     -- we need to re-snap the edge to the new nodes before adding it
-    sql := 'SELECT ST_Collect(geom) FROM ' || quote_ident(atopology)
-      || '.node WHERE node_id IN (' || start_node || ',' || end_node || ')';
+    sql := 'SELECT n1.geom as sn, n2.geom as en FROM ' || quote_ident(atopology)
+      || '.node n1, ' || quote_ident(atopology)
+      || '.node n2 WHERE n1.node_id = '
+      || start_node || ' AND n2.node_id = ' || end_node;
 #ifdef POSTGIS_TOPOLOGY_DEBUG
     RAISE DEBUG '%', sql;
 #endif
-    EXECUTE sql INTO STRICT set2;
-#ifdef POSTGIS_TOPOLOGY_DEBUG
-    RAISE DEBUG 'Endnodes: %', ST_AsText(set2);
-#endif
-    snapped := ST_Snap(rec.geom, set2, tol);
-#ifdef POSTGIS_TOPOLOGY_DEBUG
-    RAISE DEBUG 'Snapped edge: %', ST_AsText(snapped);
-#endif
+
+    EXECUTE sql INTO STRICT rec2;
+
+    snapped := ST_SetPoint(
+                 ST_SetPoint(rec.geom, ST_NPoints(rec.geom)-1, rec2.en),
+                 0, rec2.sn);
+
+    /* We might have introduced an invalidity (TODO: check this out) */
     snapped := ST_CollectionExtract(ST_MakeValid(snapped), 2);
 #ifdef POSTGIS_TOPOLOGY_DEBUG
     RAISE DEBUG 'Cleaned edge: %', ST_AsText(snapped);
 #endif
 
+
     -- Check if the so-snapped edge collapsed (see #1650)
     IF ST_IsEmpty(snapped) THEN
 #ifdef POSTGIS_TOPOLOGY_DEBUG
diff --git a/topology/test/regress/topogeo_addlinestring.sql b/topology/test/regress/topogeo_addlinestring.sql
index 6b35949e8..5162ac81c 100644
--- a/topology/test/regress/topogeo_addlinestring.sql
+++ b/topology/test/regress/topogeo_addlinestring.sql
@@ -198,7 +198,21 @@ SELECT '#1654.1', 'N', ST_AddIsoNode('city_data', 0, 'POINT(0 0)');
 SELECT check_changes();
 SELECT '#1654.2', TopoGeo_addLineString('city_data',
   'LINESTRING(-10 1, 10 1)'
-, 2);
+, 2) ORDER BY 2;
+SELECT check_changes();
+
+-- Test snapping of new edge endpoints ( http://trac.osgeo.org/postgis/ticket/1706 )
+
+DELETE FROM city_data.edge_data; DELETE FROM city_data.node; 
+DELETE FROM city_data.face where face_id > 0; 
+
+SELECT '#1706.1', 'E', TopoGeo_AddLineString('city_data',
+ 'LINESTRING(20 10, 10 10, 9 12, 10 20)');
+SELECT check_changes();
+
+SELECT '#1706.2', 'E*', TopoGeo_addLineString('city_data',
+ 'LINESTRING(10 0, 10 10, 15 10, 20 10)'
+, 4) ORDER BY 3;
 SELECT check_changes();
 
 
diff --git a/topology/test/regress/topogeo_addlinestring_expected b/topology/test/regress/topogeo_addlinestring_expected
index 1dae3b809..90ced32c6 100644
--- a/topology/test/regress/topogeo_addlinestring_expected
+++ b/topology/test/regress/topogeo_addlinestring_expected
@@ -42,9 +42,9 @@ E|15|sn12|en32
 E|33|sn32|en19
 E|34|sn31|en32
 E|35|sn32|en33
-snap|7
 snap|36
-snap|39
+snap|38
+snap|40
 N|34||POINT(18 22)
 N|35||POINT(22.4 22)
 N|36||POINT(21 20.4)
@@ -53,15 +53,16 @@ E|7|sn17|en35
 E|19|sn14|en36
 E|36|sn34|en17
 E|37|sn35|en18
-E|38|sn36|en17
-E|39|sn35|en36
+E|38|sn17|en35
+E|39|sn36|en17
+E|40|sn35|en36
 snap_again|7
 snap_again|36
-snap_again|39
-crossover|42
-crossover|44
+snap_again|40
+crossover|43
 crossover|45
 crossover|46
+crossover|47
 N|37||POINT(9 20)
 N|38||POINT(16.2 14)
 N|39||POINT(21 10)
@@ -70,91 +71,102 @@ N|41||POINT(21 7)
 E|9|sn15|en38
 E|20|sn9|en41
 E|21|sn15|en40
-E|40|sn37|en16
-E|41|sn38|en14
-E|42|sn37|en38
-E|43|sn39|en14
-E|44|sn38|en39
-E|45|sn40|en37
-E|46|sn41|en39
-crossover_again|42
-crossover_again|44
+E|41|sn37|en16
+E|42|sn38|en14
+E|43|sn37|en38
+E|44|sn39|en14
+E|45|sn38|en39
+E|46|sn40|en37
+E|47|sn41|en39
+crossover_again|43
 crossover_again|45
 crossover_again|46
+crossover_again|47
 contains|25
-contains|47
 contains|48
+contains|49
 N|42||POINT(14 34)
 N|43||POINT(7 36)
-E|47|sn42|en22
-E|48|sn21|en43
-nodecross|49
+E|48|sn42|en22
+E|49|sn21|en43
 nodecross|50
+nodecross|51
 N|44||POINT(18 37)
 N|45||POINT(22 37)
-E|49|sn44|en4
-E|50|sn4|en45
+E|50|sn44|en4
+E|51|sn4|en45
 iso_ex_2segs|28
-#1613.1|51
+#1613.1|52
 N|46||POINT(556267.6 144887)
 N|47||POINT(556267 144887.4)
-E|51|sn46|en47
-#1613.2|53
+E|52|sn46|en47
 #1613.2|54
+#1613.2|55
 N|48||POINT(556250 144887)
 N|49||POINT(556267.6 144887)
 N|50||POINT(556310 144887)
-E|51|sn46|en49
-E|52|sn49|en47
-E|53|sn48|en49
-E|54|sn49|en50
-#1631.1|55
+E|52|sn46|en49
+E|53|sn49|en47
+E|54|sn48|en49
+E|55|sn49|en50
+#1631.1|56
 N|51||POINT(556267.6 144887)
 N|52||POINT(556267.6 144888)
-E|55|sn51|en52
-#1631.2|56
+E|56|sn51|en52
 #1631.2|57
+#1631.2|58
 N|53||POINT(556254.6 144886.6)
 N|54||POINT(556267.6 144887)
-E|56|sn53|en51
-E|57|sn51|en54
-#1641.1|58
+E|57|sn53|en51
+E|58|sn51|en54
+#1641.1|59
 N|55||POINT(-0.2 0.4)
 N|56||POINT(0.2 0.4)
-E|58|sn55|en56
-#1641.2|60
+E|59|sn55|en56
 #1641.2|61
+#1641.2|62
 N|57||POINT(0 0.2)
 N|58||POINT(0 0.4)
 N|59||POINT(0 0.4)
-E|58|sn55|en58
-E|59|sn58|en56
-E|60|sn57|en58
-E|61|sn58|en59
-#1641.3|62
+E|59|sn55|en58
+E|60|sn58|en56
+E|61|sn57|en58
+E|62|sn58|en59
+#1641.3|63
 N|60||POINT(-0.2 0.4)
 N|61||POINT(0.2 0.4)
-E|62|sn60|en61
-#1641.4|64
+E|63|sn60|en61
 #1641.4|65
+#1641.4|66
 N|62||POINT(0 0.2)
 N|63||POINT(0 0.4)
 N|64||POINT(0 0.4)
-E|62|sn60|en63
-E|63|sn63|en61
-E|64|sn62|en63
-E|65|sn63|en64
+E|63|sn60|en63
+E|64|sn63|en61
+E|65|sn62|en63
+E|66|sn63|en64
 #1650.1
 N|65|0|POINT(0 0)
-#1650.3|66
+#1650.3|67
 N|66||POINT(10 0)
-E|66|sn65|en66
+E|67|sn65|en66
 #1654.1|N|67
 N|67|0|POINT(0 0)
-#1654.2|67
 #1654.2|68
+#1654.2|69
 N|68||POINT(-10 1)
 N|69||POINT(10 1)
-E|67|sn68|en67
-E|68|sn67|en69
+E|68|sn68|en67
+E|69|sn67|en69
+#1706.1|E|70
+N|70||POINT(20 10)
+N|71||POINT(10 20)
+E|70|sn70|en71
+#1706.2|E*|70
+#1706.2|E*|72
+N|72||POINT(10 0)
+N|73||POINT(9 12)
+E|70|sn70|en73
+E|71|sn73|en71
+E|72|sn72|en73
 Topology 'city_data' dropped