Mercurial > gemma
diff schema/isrs_functions.sql @ 2232:7936b46a88d4
Handle invalid multipolygons in area generation from stretch
author | Tom Gottfried <tom@intevation.de> |
---|---|
date | Wed, 13 Feb 2019 11:44:27 +0100 |
parents | f9f1babe52ae |
children | 4aabbf324e55 |
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--- a/schema/isrs_functions.sql Wed Feb 13 11:13:06 2019 +0100 +++ b/schema/isrs_functions.sql Wed Feb 13 11:44:27 2019 +0100 @@ -19,6 +19,8 @@ -- Distance marks are assumed to be near the axis and 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 @@ -79,6 +81,15 @@ ST_LineLocatePoint(axis_segment.line, to_point.geom) ), 0.0001) AS line FROM axis_segment, from_point, to_point), + 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, + ST_Dump(ST_Transform(area, z)) AS a_dmp + WHERE ST_Intersects(a_dmp.geom, axis_substring.line) + ), range_area AS ( -- Create a buffer around the clipped axis, as large as it could -- potentially be intersecting with the area polygon that @@ -90,10 +101,10 @@ axis_substring.line, ST_MaxDistance( axis_substring.line, - ST_Transform(area, z)), + area_subset.area), 'endcap=flat'), - ST_Transform(area, z)))).geom - FROM axis_substring, utm_zone) + area_subset.area))).geom + FROM axis_substring, area_subset) -- From the polygons returned by the last CTE, select only those -- around the clipped axis SELECT ST_Collect(ST_Transform(range_area.geom, ST_SRID(area)))