diff --git a/IV/tests.sql b/IV/tests.sql index 311477b..0592fa6 100644 --- a/IV/tests.sql +++ b/IV/tests.sql @@ -47,7 +47,6 @@ begin drop table if exists inflections; create table inflections (way geometry); - --insert into inflections select unnest(fix_gentle_inflections(vbends)); insert into inflections select unnest(fix_gentle_inflections(vbends)); end $$ language plpgsql; diff --git a/IV/wm.sql b/IV/wm.sql index c9d798e..f977904 100644 --- a/IV/wm.sql +++ b/IV/wm.sql @@ -44,7 +44,7 @@ begin if p3 is null then continue; end if; - cur_sign = sign(pi - st_angle(p1, p2, p2, p3)); + cur_sign = sign(pi - st_angle(p1, p2, p3)); if bend is null then bend = st_makeline(p3, p2); @@ -78,8 +78,8 @@ create or replace function fix_gentle_inflections(INOUT bends geometry[]) as $$ declare pi real; small_angle real; - phead geometry; -- head point of head bend - ptail geometry[]; -- 3 head points of tail bend + ptail geometry; -- tail point of tail bend + phead geometry[]; -- 3 tail points of head bend i int4; -- bends[i] is the current head begin pi = radians(180); @@ -87,12 +87,7 @@ begin -- be joined small_angle := radians(30); - <> - for i in select generate_subscripts(bends, 1) loop - if i = 1 then - continue; - end if; - + for i in 2..array_length(bends, 1) loop -- Predicate: two bends will always share an edge. Assuming (A,B,C,D,E,F) -- is a bend: -- C________D @@ -115,24 +110,22 @@ begin -- After processing the curve following the definition of a bend, the bend -- [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]. - select geom from st_dumppoints(bends[i]) order by path[1] desc limit 1 into phead; + select geom from st_dumppoints(bends[i-1]) order by path[1] asc limit 1 into ptail; while true loop -- copy last 3 points of bends[i-1] (tail) to ptail - select array(select 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]) order by path[1] asc limit 3 + ) into phead; -- 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 - exit bend_loop; - end if; + exit when abs(st_angle(phead[1], phead[2], phead[3]) - pi) > small_angle; - -- distance from last vertex should be larger than second-last vertex - if st_distance(phead, ptail[2]) < st_distance(phead, ptail[3]) then - exit bend_loop; - end if; + -- distance from head's first vertex should be larger than from second vertex + 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 - bends[i] = st_addpoint(bends[i], ptail[3]); - bends[i-1] = st_removepoint(bends[i-1], st_npoints(bends[i-1])-1); + bends[i] = st_removepoint(bends[i], 0); + bends[i-1] = st_addpoint(bends[i-1], phead[3]); end loop; end loop;