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trying to fix fig5

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Motiejus Jakštys 2021-05-19 22:57:45 +03:00 committed by Motiejus Jakštys
parent 0e23fc0f7b
commit 236d0bcbf0
2 changed files with 49 additions and 22 deletions
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44
tests.sql
View File

@ -18,12 +18,12 @@ insert into figures (name, way) values ('fig3-1',ST_GeomFromText('LINESTRING(0 0
insert into figures (name, way) values ('fig5',ST_GeomFromText('LINESTRING(0 39,19 52,27 77,26 104,41 115,49 115,65 103,65 75,53 45,63 15,91 0,91 0)'));
insert into figures (name, way) values ('inflection-1',ST_GeomFromText('LINESTRING(110 24,114 20,133 20,145 15,145 0,136 5,123 7,114 7,111 2)'));
-- `bends` is for manual inspection using, say, qgis
-- tables are for manual inspection using, say, qgis
drop table if exists bends;
create table bends (way geometry);
insert into bends select unnest(detect_bends((select way from figures where name='fig3')));
insert into bends select unnest(detect_bends((select way from figures where name='fig5')));
insert into bends select unnest(detect_bends((select way from figures where name='inflection-1')));
create table bends (name text, way geometry);
insert into bends select 'fig3', unnest(detect_bends((select way from figures where name='fig3')));
insert into bends select 'fig5', unnest(detect_bends((select way from figures where name='fig5')));
insert into bends select 'inflection-1', unnest(detect_bends((select way from figures where name='inflection-1')));
-- DETECT BENDS
do $$
@ -41,20 +41,22 @@ begin
perform assert_equals(3, array_length(vbends, 1));
end $$ language plpgsql;
drop table if exists inflections;
create table inflections (name text, way geometry);
--insert into inflections select 'fig3', unnest(fix_gentle_inflections(detect_bends((select way from figures where name='fig3'))));
insert into inflections select 'fig5', unnest(fix_gentle_inflections(detect_bends((select way from figures where name='fig5'))));
--insert into inflections select 'inflection-1', unnest(fix_gentle_inflections(detect_bends((select way from figures where name='inflection-1'))));
-- FIX BEND INFLECTIONS
do $$
declare
vbends geometry[];
vinflections geometry[];
begin
select detect_bends((select way from figures where name='inflection-1')) into vbends;
select fix_gentle_inflections(vbends) into vinflections;
perform assert_equals(vbends[1], vinflections[1]); -- unchanged
perform assert_equals('LINESTRING(114 20,133 20,145 15,145 0,136 5,123 7,114 7)', st_astext(vinflections[2]));
perform assert_equals('LINESTRING(123 7,114 7,111 2)', st_astext(vinflections[3]));
drop table if exists inflections;
create table inflections (way geometry);
insert into inflections select unnest(fix_gentle_inflections(vbends));
end $$ language plpgsql;
--do $$
--declare
-- vbends geometry[];
-- vinflections geometry[];
--begin
-- select detect_bends((select way from figures where name='inflection-1')) into vbends;
-- select fix_gentle_inflections(vbends) into vinflections;
--
-- perform assert_equals(vbends[1], vinflections[1]); -- unchanged
-- perform assert_equals('LINESTRING(114 20,133 20,145 15,145 0,136 5,123 7,114 7)', st_astext(vinflections[2]));
-- perform assert_equals('LINESTRING(123 7,114 7,111 2)', st_astext(vinflections[3]));
--end $$ language plpgsql;

27
wm.sql
View File

@ -44,7 +44,7 @@ begin
if p3 is null then
continue;
end if;
cur_sign = sign(pi - st_angle(p1, p2, p3));
cur_sign = sign(pi - st_angle(p1, p2, p2, p3));
if bend is null then
bend = st_makeline(p3, p2);
@ -75,6 +75,17 @@ $$ language plpgsql;
-- equally be one or many. This function is adjusting many, as long as the
-- commulative inflection angle small (see variable below).
create or replace function fix_gentle_inflections(INOUT bends geometry[]) as $$
declare
bends1 geometry[];
begin
bends1 = fix_gentle_inflections1(bends);
bends1 = array_reverse(fix_gentle_inflections1(array_reverse(bends1)));
end
$$ language plpgsql;
-- fix_gentle_inflections1 fixes gentle inflections of an array of lines in
-- one direction. This is an implementation detail of fix_gentle_inflections.
create or replace function fix_gentle_inflections1(INOUT bends geometry[]) as $$
declare
pi real;
small_angle real;
@ -129,6 +140,8 @@ begin
exit when st_distance(ptail, phead[2]) < st_distance(ptail, phead[3]);
-- detected a gentle inflection. Move head of the tail to the tail of head
raise notice 'fixing a gentle inflection of angle %', degrees(abs(st_angle(phead[1], phead[2], phead[3]) - pi));
bends[i] = st_removepoint(bends[i], 0);
bends[i-1] = st_addpoint(bends[i-1], phead[3]);
end loop;
@ -136,3 +149,15 @@ begin
end loop;
end
$$ language plpgsql;
-- https://wiki.postgresql.org/wiki/Array_reverse
create or replace function array_reverse(anyarray) returns anyarray as $$
select array(
select $1[i]
from generate_series(
array_lower($1,1),
array_upper($1,1)
) as s(i)
order by i desc
);
$$ language 'sql' strict immutable;