51 lines
1.4 KiB
PL/PgSQL
51 lines
1.4 KiB
PL/PgSQL
\i wm.sql
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-- wm_envelope clips a geometry by a bounding box around a given object,
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-- matching dimensions of A-class paper (1 by sqrt(2).
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drop function if exists wm_bbox;
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create function wm_bbox(
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center geometry,
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scaledwidth float
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) returns geometry as $$
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declare
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halfX float;
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halfY float;
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begin
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halfX = scaledwidth / 2;
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halfY = halfX * sqrt(2);
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return st_envelope(
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st_union(
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st_translate(center, halfX, halfY),
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st_translate(center, -halfX, -halfY)
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)
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);
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end
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$$ language plpgsql;
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insert into wm_visuals(name, way) values('salvis', (
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select st_intersection(
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(select st_union(way) from wm_rivers where name in ('Šalčia', 'Visinčia')),
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wm_bbox(
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st_closestpoint(
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(select way from wm_rivers where name='Šalčia'),
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(select way from wm_rivers where name='Visinčia')
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),
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:scaledwidth
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)
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)
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));
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do $$
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declare
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npoints bigint;
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secs bigint;
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begin
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select * from ST_SimplifyWM_Estimate((select st_union(way) from wm_rivers)) into npoints, secs;
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raise notice 'Total points: %', npoints;
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raise notice 'Expected duration: %s (+-%s)', ceil(secs), floor(secs*.5);
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end $$ language plpgsql;
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delete from wm_debug where name in (select distinct name from wm_rivers);
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delete from wm_demo where name in (select distinct name from wm_rivers);
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insert into wm_demo (name, way) select name, ST_SimplifyWM(way, name) from wm_rivers;
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