Mercurial > gemma
view schema/geo_functions.sql @ 3733:ec86a7155377 concave-hull
Estimated too large triangles as triangles which have an edge which is at least 3.5 times as long as the standard dev of the longest egde per inner triangle.
author | Sascha L. Teichmann <sascha.teichmann@intevation.de> |
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date | Mon, 24 Jun 2019 11:39:09 +0200 |
parents | eeeb7bf14217 |
children |
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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): -- * Sascha L. Teichmann <sascha.teichmann@intevation.de> -- * Tom Gottfried <tom@intevation.de> CREATE OR REPLACE FUNCTION best_utm(g geography) RETURNS integer AS $$ DECLARE center geometry; BEGIN -- Centroid should be calculated on geography to get accurate results -- from lon/lat coordinates, but the respective PostGIS function returns -- POINT(-NaN NaN) for some invalid polygons, while the calculation on -- geometry seems to give reasonable approximations in this context. SELECT ST_Centroid(CAST(g AS geometry)) INTO center; RETURN CASE WHEN ST_Y(center) > 0 THEN 32600 ELSE 32700 END + floor((ST_X(center)+180)/6)::int + 1; END; $$ LANGUAGE plpgsql IMMUTABLE;