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bend_attrs now go to a dedicated type

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Motiejus Jakštys 2021-05-19 22:57:46 +03:00 committed by Motiejus Jakštys
parent c12326202c
commit c5b870b2ae
2 changed files with 33 additions and 20 deletions
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6
tests.sql
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@ -54,7 +54,11 @@ insert into demo_selfcrossing3 select name, generate_subscripts(ways, 1), unnest
-- BEND ATTRS
do $$
begin perform bend_attrs(ways, true) from inflections; end
declare
recs t_bend_attrs[];
begin
select array(select bend_attrs(ways, true) from inflections) into recs;
end
$$ language plpgsql;
-- COMBINED

47
wm.sql
View File

@ -267,45 +267,54 @@ end
$$ language plpgsql;
drop function if exists bend_attrs;
create function bend_attrs(bends geometry[], dbg boolean default false) returns table(bend geometry, area real, cmp real, adjsize real) as $$
drop type if exists t_bend_attrs;
create type t_bend_attrs as (
bend geometry,
area real,
cmp real,
adjsize real
);
create function bend_attrs(bends geometry[], dbg boolean default false) returns setof t_bend_attrs as $$
declare
i int4;
fourpi real;
polygon geometry;
bend geometry;
res t_bend_attrs;
begin
fourpi = 4*radians(180);
for i in 1..array_length(bends, 1) loop
bend = bends[i];
if st_numpoints(bend) < 3 then
cmp = 0;
area = 0;
res.cmp = 0;
res.area = 0;
res.bend = null;
polygon = null;
else
select st_makepolygon(st_addpoint(bend, st_startpoint(bend))) into polygon;
-- Compactness Index (cmp) is defined as "the ratio of the area of the
-- polygon over the circle whose circumference length is the same as the
-- length of the circumference of the polygon". I assume they meant the
-- area of the circle. So here goes:
-- 1. get polygon area P.
-- 2. get polygon perimeter = u. Pretend it's our circle's circumference.
-- 3. get A (area) of the circle from u: A = (u^2)/(4*pi)
-- 4. divide P by A: cmp = P/A = P/((u^2)*4*pi) = 4*pi*P/u^2
select st_area(polygon) into res.area;
select fourpi*res.area/(st_perimeter(polygon)^2) into res.cmp;
select bend into res.bend;
end if;
-- Compactness Index (cmp) is defined as "the ratio of the area of the
-- polygon over the circle whose circumference length is the same as the
-- length of the circumference of the polygon". I assume they meant the
-- area of the circle. So here goes:
-- 1. get polygon area P.
-- 2. get polygon perimeter = u. Pretend it's our circle's circumference.
-- 3. get A (area) of the circle from circumference u := (u^2)/(4*pi)
-- 4. divide area by A: cmp = P/((u^2)*4*pi) = 4*pi*P/u^2
if polygon is not null then
select st_area(polygon) into area;
select fourpi*area/(st_perimeter(polygon)^2) into cmp;
end if;
if area > 0 then
select (area*(0.75/cmp)) into adjsize;
if res.area > 0 then
select (res.area*(0.75/res.cmp)) into res.adjsize;
end if;
if dbg then
insert into debug_wm (name, way, props) values(
'bend_attrs_' || i,
bend,
json_build_object('area', area, 'cmp', cmp, 'adjsize', adjsize)
json_build_object('area', res.area, 'cmp', res.cmp, 'adjsize', res.adjsize)
);
end if;
return next;
return next res;
end loop;
end;
$$ language plpgsql;