topology.GetEdgeByPoint: implementation and regress test, by Andrea Peri. Ticket...

git-svn-id: http://svn.osgeo.org/postgis/trunk@6864 b70326c6-7e19-0410-871a-916f4a2858ee

diff --git a/topology/Makefile.in b/topology/Makefile.in
index 76ee498140f292917f693641727281af26a30dd7..5cd4eb33b8cd2988975e9667dbc96741feb7cffa 100644 (file)
--- a/topology/Makefile.in
+++ b/topology/Makefile.in
@@ -42,7 +42,7 @@ endif
 $(SQL_OBJS): %.in: %.in.c
        $(CPP) -traditional-cpp $< | grep -v '^#' > $@
 
-topology.sql.in: sql/sqlmm.sql sql/populate.sql sql/gml.sql
+topology.sql.in: sql/sqlmm.sql sql/populate.sql sql/gml.sql sql/query/getnodebypoint.sql
 
 check: topology.sql
        $(MAKE) -C test $@

diff --git a/topology/sql/query/getnodebypoint.sql b/topology/sql/query/getnodebypoint.sql
new file mode 100644 (file)
index 0000000..87bbf0b
--- /dev/null
+++ b/topology/sql/query/getnodebypoint.sql
@@ -0,0 +1,89 @@
+-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+-- 
+-- PostGIS - Spatial Types for PostgreSQL
+-- http://postgis.refractions.net
+--
+-- Copyright (C) 2011 Andrea Peri
+--
+-- This is free software; you can redistribute and/or modify it under
+-- the terms of the GNU General Public Licence. See the COPYING file.
+--
+-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+-- {
+--
+-- Andrea Peri (19 Jan 2011) creation
+-- Andrea Peri (14 Feb 2011) minor issues
+--
+-- getnodebypoint(atopology, point, tolerance)
+--
+-- Retrieve a Node ID given a POINT and a tolerance
+-- tolerance = 0 mean exactly intersection
+--
+-- Returns the integer ID if there is a Node on the Point.
+--
+-- If there isn't any node in the Point, GetNodeByPoint return 0.
+--
+-- if near the point there are two or more nodes it throw an exception.
+--
+CREATE OR REPLACE FUNCTION topology.GetNodeByPoint(atopology varchar, apoint geometry, tol1 float8)
+       RETURNS int
+AS
+$$
+DECLARE
+       sql text;
+       idnode int;
+BEGIN
+       --
+       -- Atopology and apoint are required
+       -- 
+       IF atopology IS NULL OR apoint IS NULL THEN
+               RAISE EXCEPTION 'Invalid null argument';
+       END IF;
+
+       --
+       -- Apoint must be a point
+       --
+       IF substring(geometrytype(apoint), 1, 5) != 'POINT'
+       THEN
+               RAISE EXCEPTION 'Node geometry must be a point';
+       END IF;
+
+       --
+       -- Tolerance must be >= 0
+       --
+       IF tol1 < 0
+       THEN
+               RAISE EXCEPTION 'Tolerance must be >=0';
+       END IF;
+
+
+    if tol1 = 0 then
+       sql := 'SELECT a.node_id FROM ' 
+        || quote_ident(atopology) 
+        || '.node as a WHERE '
+        || '(a.geom && ' || quote_literal(apoint::text)||'::geometry) '
+        || ' AND (ST_Intersects(a.geom,' || quote_literal(apoint::text)||'::geometry) );';
+    else
+       sql := 'SELECT a.node_id FROM ' 
+        || quote_ident(atopology) 
+        || '.node as a WHERE '
+        || '(ST_DWithin(a.geom,' || quote_literal(apoint::text)||'::geometry,' || tol1::text || ') );';
+    end if;
+
+    BEGIN
+    EXECUTE sql INTO STRICT idnode;
+    EXCEPTION
+        WHEN NO_DATA_FOUND THEN
+            idnode = 0;
+        WHEN TOO_MANY_ROWS THEN
+            RAISE EXCEPTION 'Two or more nodes founded';
+    END;
+
+       RETURN idnode;
+       
+END
+$$
+LANGUAGE 'plpgsql' STRICT;
+--} GetNodeByPoint
+

diff --git a/topology/test/Makefile b/topology/test/Makefile
index 0733e74d8141f83c5bd9ec5cd344fd10d1a77122..2de17963a53a98253b72976d7a008dea39334449 100644 (file)
--- a/topology/test/Makefile
+++ b/topology/test/Makefile
@@ -31,7 +31,8 @@ TESTS = regress/legacy_validate.sql regress/legacy_predicate.sql \
        regress/topoelementarray_agg.sql \
        regress/droptopology.sql \
        regress/createtopogeom.sql \
-       regress/gml.sql
+       regress/gml.sql \
+       regress/getnodebypoint.sql
 
 check: topo_predicates.sql load_topology.sql load_topology-4326.sql
        $(MAKE) -C ../../regress postgis.sql staged-install

diff --git a/topology/test/regress/getnodebypoint.sql b/topology/test/regress/getnodebypoint.sql
new file mode 100644 (file)
index 0000000..9182fa9
--- /dev/null
+++ b/topology/test/regress/getnodebypoint.sql
@@ -0,0 +1,30 @@
+set client_min_messages to WARNING;
+
+SELECT topology.CreateTopology('schema_topo') > 0;
+
+select topology.AddEdge('schema_topo',ST_GeomFromText('LINESTRING(1 4, 4 7)')) = 1;
+select topology.AddEdge('schema_topo',ST_GeomFromText('LINESTRING(4 7, 6 9)')) = 2;
+select topology.AddEdge('schema_topo',ST_GeomFromText('LINESTRING(2 2, 4 4)')) = 3;
+select topology.AddEdge('schema_topo',ST_GeomFromText('LINESTRING(4 4, 5 5, 6 6)')) = 4;
+select topology.AddEdge('schema_topo',ST_GeomFromText('LINESTRING(6 6, 6 9)')) = 5;
+
+-- ask on a Point with tolerance zero
+select topology.GetNodeByPoint('schema_topo',ST_GeomFromText('POINT(5 5)'), 0::float8);
+
+-- ask on a Point on a node with tolerance
+select topology.GetNodeByPoint('schema_topo',ST_GeomFromText('POINT(4 4)'), 0::float8);
+
+-- Ask for a point outside from an edge with a tolerance sufficient to include one node
+select topology.GetNodeByPoint('schema_topo',ST_GeomFromText('POINT(4.1 4)'), 0.3::float8);
+
+-- Ask for a point where there isn't a node
+select topology.GetNodeByPoint('schema_topo',ST_GeomFromText('POINT(5 5.5)'), 0::float8) = 0;
+
+
+-- Failing cases (should all raise exceptions) -------
+
+-- Ask for a Point with a tollerance too high
+select topology.GetNodeByPoint('schema_topo',ST_GeomFromText('POINT(4 7)'), 5::float8);
+
+
+SELECT topology.DropTopology('schema_topo');

diff --git a/topology/test/regress/getnodebypoint_expected b/topology/test/regress/getnodebypoint_expected
new file mode 100644 (file)
index 0000000..fc0d7a3
--- /dev/null
+++ b/topology/test/regress/getnodebypoint_expected
@@ -0,0 +1,12 @@
+t
+t
+t
+t
+t
+t
+0
+5
+5
+t
+ERROR:  Two or more nodes founded
+Topology 'schema_topo' dropped

diff --git a/topology/topology.sql.in.c b/topology/topology.sql.in.c
index 293abfd78fa3a2c6df3a98a03f293edb636106b5..3914c6143102679aec59a5cb0920a51ca6921072 100644 (file)
--- a/topology/topology.sql.in.c
+++ b/topology/topology.sql.in.c
@@ -2411,6 +2411,9 @@ LANGUAGE 'plpgsql' VOLATILE STRICT;
 
 --=} POSTGIS-SPECIFIC topology predicates
 
+--  Querying
+#include "sql/query/getnodebypoint.sql"
+
 --  Editing
 #include "sql/populate.sql"