Mercurial > gemma
view schema/isrs_functions.sql @ 2501:9d9c6425db82 critical-bottlenecks
merged default into critical-bottlenecks branch
author | Markus Kottlaender <markus@intevation.de> |
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date | Mon, 04 Mar 2019 16:01:20 +0100 |
parents | 54c9fe587fe6 |
children | 79f4a20e31c2 |
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-- This is Free Software under GNU Affero General Public License v >= 3.0 -- without warranty, see README.md and license for details. -- SPDX-License-Identifier: AGPL-3.0-or-later -- License-Filename: LICENSES/AGPL-3.0.txt -- Copyright (C) 2018, 2019 by via donau -- – Österreichische Wasserstraßen-Gesellschaft mbH -- Software engineering by Intevation GmbH -- Author(s): -- * Tom Gottfried <tom@intevation.de> -- * Sascha Wilde <wilde@intevation.de> CREATE OR REPLACE FUNCTION best_utm(stretch isrsrange) RETURNS integer AS $$ SELECT best_utm(ST_Collect(geom::geometry)) FROM waterway.distance_marks_virtual WHERE location_code IN (lower(stretch), upper(stretch)) $$ LANGUAGE sql STABLE PARALLEL SAFE; -- Clip waterway axis to a stretch given by a pair of ISRS location codes. -- Uses the table waterway.distance_marks_virtual to map ISRS location codes -- to their geo-location. -- Distance marks are assumed to be near the axis. CREATE OR REPLACE FUNCTION ISRSrange_axis(stretch isrsrange) RETURNS geometry AS $$ WITH RECURSIVE -- Get coordinates of location codes points_geog AS ( SELECT geom FROM waterway.distance_marks_virtual WHERE location_code = lower(stretch) OR location_code = upper(stretch)), utm_zone AS ( -- Find best matchting UTM zone SELECT best_utm(stretch) AS z), axis AS ( SELECT id, ST_Transform(wtwaxs::geometry, z) AS wtwaxs FROM waterway.waterway_axis, utm_zone), -- In order to guarantee the following ST_Covers to work, -- snap distance mark coordinates to axis points AS ( SELECT ST_ClosestPoint( wtwaxs, ST_Transform(points_geog.geom::geometry, z)) AS geom FROM points_geog, utm_zone, ( SELECT ST_Collect(wtwaxs) AS wtwaxs FROM axis) AS ax), axis_snapped AS ( -- Iteratively connect non-contiguous axis chunks -- to find the contiguous axis on which given distance marks lie (SELECT ARRAY[id] AS ids, wtwaxs FROM axis, points WHERE ST_Intersects( ST_Buffer(axis.wtwaxs, 0.0001), points.geom) FETCH FIRST ROW ONLY) UNION -- Connect endpoint of next linestring with closest -- endpoint of merged linestring until a contiguous -- linestring connecting both distance marks is build up (SELECT refids || id, ST_LineMerge(ST_Collect(ARRAY( -- Linestring build up so far SELECT refgeom UNION -- Fill eventual gap SELECT ST_ShortestLine( ST_Boundary(refgeom), ST_Boundary(geom)) UNION -- Linestring to be added SELECT geom))) FROM axis_snapped AS axis_snapped (refids, refgeom), axis AS axis (id, geom), (SELECT ST_Collect(points.geom) AS pts FROM points) AS points WHERE id <> ALL(refids) AND NOT ST_Covers(ST_Buffer(refgeom, 0.0001), points.pts) ORDER BY ST_Distance(ST_Boundary(refgeom), ST_Boundary(geom)) FETCH FIRST ROW ONLY)), axis_segment AS ( -- Fetch end result from snapping SELECT wtwaxs AS line FROM axis_snapped WHERE array_length(ids, 1) = ( SELECT max(array_length(ids, 1)) FROM axis_snapped)) -- Use linear referencing to clip axis between distance marks. -- Simplification is used to work-around the problem, that -- ST_LineSubstring might generate very small line segments at an -- end of the resulting linestring, that significantly differ from -- the direction of the input linestring due to finite precision -- of the calculation. The generated small segment of the -- resulting line leads to unexpected results of the buffer with -- endcap=flat in the CTE below. SELECT ST_SimplifyPreserveTopology(ST_LineSubstring( axis_segment.line, min(fractions.f), max(fractions.f)), 0.0001) AS line FROM axis_segment, LATERAL ( SELECT ST_LineLocatePoint(axis_segment.line, points.geom) AS f FROM points) AS fractions GROUP BY axis_segment.line $$ LANGUAGE sql STABLE PARALLEL SAFE; -- Clip an area to a stretch given by a pair of ISRS location codes. -- Uses ISRSrange_axis() to retrieve the respective clipped axis used to find -- perpendicular direction at geo-locations of ISRS codes. -- The area passed as argument is assumed to intersect with the axis -- (use e.g. waterway area or fairway dimensions). -- If a multipolygon is passed, the union of the polygons intersecting with the -- relevant part of the axis is used for clipping. CREATE OR REPLACE FUNCTION ISRSrange_area( stretch isrsrange, area geometry ) RETURNS geometry AS $$ WITH axis_substring AS ( SELECT ISRSrange_axis(stretch) AS line), utm_zone AS ( SELECT best_utm(stretch) AS z), area_subset AS ( -- In case area is a multipolygon, process the union of those -- polygons, which intersect with the axis. The union is to avoid -- problems with invalid/self-intersecting multipolygons SELECT ST_Union(a_dmp.geom) AS area FROM axis_substring, utm_zone, LATERAL ( SELECT ST_MakeValid(ST_Transform(geom, z)) AS geom FROM ST_Dump(area)) AS a_dmp WHERE ST_Intersects(a_dmp.geom, axis_substring.line) ), rotated_ends AS ( SELECT ST_Collect(ST_Scale( ST_Translate(e, (ST_X(p1) - ST_X(p2)) / 2, (ST_Y(p1) - ST_Y(p2)) / 2), ST_Point(d, d), p1)) AS blade FROM axis_substring, area_subset, LATERAL (SELECT i, ST_PointN(line, i) AS p1 FROM (VALUES (1), (-1)) AS idx (i)) AS ep, ST_Rotate(ST_PointN(line, i*2), pi()/2, p1) AS ep2 (p2), ST_Makeline(p1, p2) AS e (e), LATERAL (SELECT (ST_MaxDistance(p1, area) / ST_Length(e)) * 2) AS d (d)), range_area AS ( -- Split area by orthogonal lines at the ends of the clipped axis SELECT (ST_Dump(ST_CollectionExtract( ST_Split(area, blade), 3))).geom FROM area_subset, rotated_ends) -- From the polygons returned by the last CTE, select only those -- around the clipped axis SELECT ST_Multi(ST_Transform(ST_Union(range_area.geom), ST_SRID(area))) FROM axis_substring, range_area WHERE ST_Intersects(ST_Buffer(range_area.geom, -0.0001), axis_substring.line) $$ LANGUAGE sql;