27 lines
661 B
MySQL
27 lines
661 B
MySQL
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create or replace function detect_bends(line geometry) returns table(bend geometry) as $$
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/* for each bend, should return:
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- size (area)
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- shape (cmp, compactness index)
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*/
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declare
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pi real;
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p geometry;
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p1 geometry;
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p2 geometry;
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p3 geometry;
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begin
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pi = radians(180);
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for p in (select (dp).geom from st_dumppoints(line) as dp) loop
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p3 = p2;
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p2 = p1;
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p1 = p;
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if p3 is null then continue; end if;
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raise notice 'ANGLE %', degrees(pi - st_angle(p1, p2, p2, p3));
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end loop;
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end
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$$ language plpgsql;
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drop table if exists bends;
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create table bends as (select * from detect_bends((select way from figures where name='fig3')));
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