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fix example inflection-1

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Motiejus Jakštys 2021-05-19 22:57:45 +03:00 committed by Motiejus Jakštys
parent 198ea6d0e3
commit e76efda436
2 changed files with 12 additions and 10 deletions
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3
tests.sql
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@ -16,7 +16,7 @@ create table figures (name text, way geometry);
insert into figures (name, way) values ('fig3',ST_GeomFromText('LINESTRING(0 0,12 0,13 4,20 2,20 0,32 0,33 10,38 16,43 15,44 10,44 0,60 0)'));
insert into figures (name, way) values ('fig3-1',ST_GeomFromText('LINESTRING(0 0,12 0,13 4,20 2,20 0,32 0,33 10,38 16,43 15,44 10,44 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(129 45,131 56,130 82,128 99,147 104,149 89,147 68,141 52)'));
insert into figures (name, way) values ('inflection-1',ST_GeomFromText('LINESTRING(100 14,114 20,133 20,145 15,145 0,136 5,123 7,114 7,111 2)'));
drop table if exists bends;
create table bends (way geometry);
@ -35,7 +35,6 @@ begin
perform assert_equals('LINESTRING(20 2,20 0,32 0,33 10)', st_astext(bends[3]));
perform assert_equals('LINESTRING(32 0,33 10,38 16,43 15,44 10,44 0)', st_astext(bends[4]));
perform assert_equals(4, array_length(detect_bends((select way from figures where name='fig3-1')), 1));
select detect_bends((select way from figures where name='fig5')) into bends;

19
wm.sql
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@ -99,18 +99,21 @@ begin
-- Then edges (A,B) and (E,F) are shared with the neighboring bends.
--
--
-- Assume this curve:
-- Assume this curve (figure `inflection-1`):
--
-- A______B
-- ---' `---.___. E
-- C D |
-- _I |
-- '---.________ |
-- H G'---+ F
-- ---' `-------. C
-- |
-- G___ F |
-- / `-----.____+ D
-- E
--
-- After processing the curve following the definition of a bend, the bend
-- [A-G] would be detected. Assuming inflection point G and H are "small",
-- the bend would be extended by two edges to [A,I].
-- [A-E] would be detected. Assuming inflection point E and F are "small",
-- the bend needs to be extended by two edges to [A,G].
--
-- Assuming the direction in this example is clock-wise, the first set of
-- `p` variables will be: p1=C, p2=B, p3=A.
for p in (select geom from st_dumppoints(prev_bend) order by path[1] desc) loop
p3 = p2;
p2 = p1;