diff --git a/wm.sql b/wm.sql index 1e0db66..e26d615 100644 --- a/wm.sql +++ b/wm.sql @@ -265,28 +265,26 @@ drop function if exists bend_attrs; drop type if exists t_bend_attrs; create type t_bend_attrs as ( bend geometry, - area real, - cmp real, - adjsize real, - baselinelength real + area real not null default 0, + cmp real not null default 0, + adjsize real not null default 0, + baselinelength real not null default 0 ); create function bend_attrs(bends geometry[], dbgname text default null) returns setof t_bend_attrs as $$ declare + fourpi constant real default 4*radians(180); i int4; - fourpi real; polygon geometry; bend geometry; res t_bend_attrs; begin - fourpi = 4*radians(180); for i in 1..array_length(bends, 1) loop - res = null; bend = bends[i]; - if st_numpoints(bend) < 3 then - polygon = null; - else - select st_makepolygon(st_addpoint(bend, st_startpoint(bend))) into polygon; - select st_distance(st_startpoint(bend), st_endpoint(bend)) into res.baselinelength; + res = null; + res.bend = bend; + if st_numpoints(bend) >= 3 then + polygon = st_makepolygon(st_addpoint(bend, st_startpoint(bend))); + res.baselinelength = st_distance(st_startpoint(bend), st_endpoint(bend)); -- Compactness Index (cmp) is defined as "the ratio of the area of the -- polygon over the circle whose circumference length is the same as the -- length of the circumference of the polygon". I assume they meant the @@ -295,13 +293,11 @@ begin -- 2. get polygon perimeter = u. Pretend it's our circle's circumference. -- 3. get A (area) of the circle from u: A = (u^2)/(4*pi) -- 4. divide P by A: cmp = P/A = P/((u^2)*4*pi) = 4*pi*P/u^2 - select st_area(polygon) into res.area; - select fourpi*res.area/(st_perimeter(polygon)^2) into res.cmp; - select bend into res.bend; - end if; - - if res.area > 0 then - select (res.area*(0.75/res.cmp)) into res.adjsize; + res.area = st_area(polygon); + res.cmp = fourpi*res.area/(st_perimeter(polygon)^2); + if res.cmp > 0 then + res.adjsize = (res.area*(0.75/res.cmp)); + end if; end if; if dbgname is not null then @@ -318,7 +314,9 @@ begin ) ); end if; + return next res; + end loop; end; $$ language plpgsql;