Mercurial > gemma
view schema/geo_functions.sql @ 5203:355195a90298 new-fwa
Start calculting the navigability. TODO: accumulate and do output.
author | Sascha L. Teichmann <sascha.teichmann@intevation.de> |
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date | Fri, 08 May 2020 18:59:14 +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;