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https://git.osgeo.org/gitea/postgis/postgis
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116 lines
2.9 KiB
PL/PgSQL
116 lines
2.9 KiB
PL/PgSQL
-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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--
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-- PostGIS - Spatial Types for PostgreSQL
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-- http://postgis.refractions.net
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--
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-- Copyright (C) 2010 Sandro Santilli <strk@keybit.net>
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--
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-- This is free software; you can redistribute and/or modify it under
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-- the terms of the GNU General Public Licence. See the COPYING file.
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--
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-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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--
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-- Functions used to populate a topology
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--
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-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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--
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-- Developed by Sandro Santilli <strk@keybit.net>
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-- for Faunalia (http://www.faunalia.it) with funding from
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-- Regione Toscana - Sistema Informativo per la Gestione del Territorio
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-- e dell' Ambiente [RT-SIGTA].
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-- For the project: "Sviluppo strumenti software per il trattamento di dati
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-- geografici basati su QuantumGIS e Postgis (CIG 0494241492)"
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--
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-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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--{
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--
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-- AddNode(atopology, point)
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--
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-- Add a node primitive to a topology and get it's identifier.
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-- Returns an existing node at the same location, if any.
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--
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-- When adding a _new_ node it checks for the existance of any
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-- edge crossing the given point, raising an exception if found.
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--
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-- The newly added nodes have no containing face.
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--
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--
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CREATE OR REPLACE FUNCTION topology.AddNode(varchar, geometry)
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RETURNS int
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AS
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$$
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DECLARE
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atopology ALIAS FOR $1;
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apoint ALIAS FOR $2;
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nodeid int;
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rec RECORD;
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BEGIN
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--
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-- Atopology and apoint are required
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--
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IF atopology IS NULL OR apoint IS NULL THEN
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RAISE EXCEPTION 'Invalid null argument';
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END IF;
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--
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-- Apoint must be a point
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--
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IF substring(geometrytype(apoint), 1, 5) != 'POINT'
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THEN
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RAISE EXCEPTION 'Node geometry must be a point';
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END IF;
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--
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-- Check if a coincident node already exists
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--
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-- We use index AND x/y equality
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--
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FOR rec IN EXECUTE 'SELECT node_id FROM '
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|| quote_ident(atopology) || '.node ' ||
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'WHERE geom && ' || quote_literal(apoint::text) || '::geometry'
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||' AND x(geom) = x('||quote_literal(apoint::text)||'::geometry)'
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||' AND y(geom) = y('||quote_literal(apoint::text)||'::geometry)'
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LOOP
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RETURN rec.node_id;
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END LOOP;
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--
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-- Check if any edge crosses this node
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-- (endpoints are fine)
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--
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FOR rec IN EXECUTE 'SELECT edge_id FROM '
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|| quote_ident(atopology) || '.edge '
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|| 'WHERE ST_Crosses(' || quote_literal(apoint::text)
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|| ', geom)'
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LOOP
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RAISE EXCEPTION
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'An edge crosses the given node.';
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END LOOP;
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--
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-- Get new node id from sequence
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--
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FOR rec IN EXECUTE 'SELECT nextval(''' ||
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atopology || '.node_node_id_seq'')'
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LOOP
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nodeid = rec.nextval;
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END LOOP;
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--
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-- Insert the new row
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--
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EXECUTE 'INSERT INTO ' || quote_ident(atopology)
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|| '.node(node_id, geom)
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VALUES('||nodeid||','||quote_literal(apoint::text)||
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')';
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RETURN nodeid;
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END
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$$
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LANGUAGE 'plpgsql';
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--} AddNode
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