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debugging inflections

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Motiejus Jakštys 2021-02-26 10:41:38 +02:00
parent 5cb3f6aea6
commit 733c7f409a
2 changed files with 4 additions and 2 deletions
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2
IV/tests.sql
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@ -48,6 +48,6 @@ begin
drop table if exists inflections;
create table inflections (way geometry);
--insert into inflections select unnest(fix_gentle_inflections(vbends));
select fix_gentle_inflections(vbends);
insert into inflections select unnest(fix_gentle_inflections(vbends));
end $$ language plpgsql;

4
IV/wm.sql
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@ -76,11 +76,13 @@ $$ language plpgsql;
-- commulative inflection angle small (see variable below).
create or replace function fix_gentle_inflections(INOUT bends geometry[]) as $$
declare
pi real;
small_angle real;
phead geometry; -- head point of head bend
ptail geometry[]; -- 3 head points of tail bend
i int4; -- bends[i] is the current head
begin
pi = radians(180);
-- the threshold when the angle is still "small", so gentle inflections can
-- be joined
small_angle := radians(30);
@ -116,7 +118,7 @@ begin
select geom from st_dumppoints(bends[i]) order by path[1] desc limit 1 into phead;
while true loop
-- copy last 3 points of bends[i-1] (tail) to ptail
select array_agg(geom) from st_dumppoints(bends[i-1]) order by path[1] desc limit 3 into ptail;
select array(select geom from st_dumppoints(bends[i-1]) order by path[1] desc limit 3) into ptail;
-- if inflection angle between ptail[1:3] "large", stop processing this bend
if abs(st_angle(ptail[1], ptail[2], ptail[2], ptail[3]) - pi) > small_angle then