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exaggeration

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This commit is contained in:
Motiejus Jakštys 2021-05-05 09:15:37 +03:00
parent 4cb7bf9003
commit 93cca2e7ea
3 changed files with 114 additions and 80 deletions
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3
IV/Makefile
View File

@ -1,5 +1,6 @@
OSM ?= lithuania-latest.osm.pbf
WHERE ?= name='Visinčia' OR name='Šalčia' OR name='Nemunas' OR name='Merkys'
#WHERE ?= name='Visinčia' OR name='Šalčia' OR name='Nemunas' OR name='Merkys'
WHERE ?= name='Šalčia'
#WHERE ?= name like '%'
SLIDES = slides-2021-03-29.pdf

13
IV/test.sql
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@ -51,10 +51,15 @@ insert into wm_figures (name, way) values ('multi-island','MULTILINESTRING((-15
insert into wm_figures (name, way) values ('selfcrossing-1','LINESTRING(-27 180,-20 166,-21 142,-18 136,55 136,55 136,71 145,44 165,37 146,22 145,14 164,11 164,3 146,-12 146,-13 176,-18 184)'::geometry);
insert into wm_figures (name, way) values ('selfcrossing-1-rev',ST_Reverse(ST_Translate((select way from wm_figures where name='selfcrossing-1'), 0, 60)));
insert into wm_figures (name, way) values ('isolated-1','LINESTRING(-56 103,-54 102,-30 103,-31 105,-31 108,-27 108,-26 103,0 103,2 104)'::geometry);
insert into wm_figures(name, way) values ('isolated-2', 'LINESTRING(2801325.2746406365 7226746.592740034,2801316.313421628 7226773.775365548,2801310.6472595464 7226787.509780527,2801304.0682776407 7226795.559684921,2801288.850903249 7226806.013127576,2801251.525477986 7226819.15625314,2801231.821928116 7226826.614843614,2801216.2928591496 7226837.373539025,2801207.331640141 7226849.009733273,2801203.7471525376 7226861.847718405,2801201.954908736 7226876.478850377,2801196.2887466545 7226884.853135042,2801186.1364090946 7226892.903139205)');
delete from wm_debug where name in (select distinct name from wm_figures);
delete from wm_demo where name in (select distinct name from wm_figures);
insert into wm_demo (name, way) select name, ST_SimplifyWM(way, .1, name) from wm_figures where name != 'fig8';
insert into wm_demo (name, way) select name, ST_SimplifyWM(way, 11, name) from wm_figures where name = 'fig8';
insert into wm_demo (name, way) select name, ST_SimplifyWM(way, .1, name) from wm_figures where name not in ('fig8', 'isolated-1');
insert into wm_demo (name, way) select name, ST_SimplifyWM(way, 11, name) from wm_figures where name in ('fig8', 'isolated-1');
do $$
@ -189,7 +194,7 @@ begin
perform assert_equals(fig8gen3, st_astext(eliminations[3]));
end $$ language plpgsql;
-- testing wm_exaggerate in isolation
-- testing wm_exaggerate_bend in isolation
do $$
declare
fig3b2 geometry;
@ -198,6 +203,6 @@ declare
begin
select way from wm_debug where name='fig3' and stage='bbends' and gen=1 and nbend=2 into fig3b2;
size = wm_adjsize(fig3b2);
bend = wm_exaggerate(fig3b2, size, 50.);
bend = wm_exaggerate_bend(fig3b2, size, 50.);
insert into wm_debug(stage, name, gen, nbend, way) values('manual', 'fig3', 1, 1, bend);
end $$ language plpgsql;

178
IV/wm.sql
View File

@ -22,6 +22,7 @@ declare
begin
l_type = st_geometrytype(line);
if l_type != 'ST_LineString' then
raise notice 'Got non-LineString: %', st_astext(line);
raise 'This function works with ST_LineString, got %', l_type;
end if;
@ -76,12 +77,7 @@ begin
if dbgname is not null then
for i in 1..array_length(bends, 1) loop
insert into wm_debug(stage, name, gen, nbend, way) values(
'bbends',
dbgname,
dbggen,
i,
bends[i]
);
'bbends', dbgname, dbggen, i, bends[i]);
dbgpolygon = null;
if st_npoints(bends[i]) >= 3 then
@ -91,12 +87,7 @@ begin
);
end if;
insert into wm_debug(stage, name, gen, nbend, way) values(
'bbends-polygon',
dbgname,
dbggen,
i,
dbgpolygon
);
'bbends-polygon', dbgname, dbggen, i, dbgpolygon);
end loop;
end if;
end
@ -137,12 +128,7 @@ begin
if dbgname is not null then
for i in 1..array_length(bends, 1) loop
insert into wm_debug(stage, name, gen, nbend, way) values(
'cinflections',
dbgname,
dbggen,
i,
bends[i]
);
'cinflections', dbgname, dbggen, i, bends[i]);
dbgpolygon = null;
if st_npoints(bends[i]) >= 3 then
@ -153,12 +139,7 @@ begin
end if;
insert into wm_debug(stage, name, gen, nbend, way) values(
'cinflections-polygon',
dbgname,
dbggen,
i,
dbgpolygon
);
'cinflections-polygon', dbgname, dbggen, i, dbgpolygon);
end loop;
end if;
end
@ -171,7 +152,7 @@ create function wm_fix_gentle_inflections1(INOUT bends geometry[]) as $$
declare
-- the threshold when the angle is still "small", so gentle inflections can
-- be joined
small_angle constant real default radians(45);
small_angle constant real default pi()/4;
ptail geometry; -- tail point of tail bend
phead geometry[]; -- 3 tail points of head bend
i int4; -- bends[i] is the current head
@ -321,10 +302,7 @@ begin
if dbgname is not null then
insert into wm_debug(stage, name, gen, nbend, way) values(
'dcrossings',
dbgname,
dbggen,
generate_subscripts(bends, 1),
'dcrossings', dbgname, dbggen, generate_subscripts(bends, 1),
unnest(bends)
);
end if;
@ -389,11 +367,7 @@ begin
if dbgname is not null then
insert into wm_debug (stage, name, gen, nbend, way, props) values(
'ebendattrs',
dbgname,
dbggen,
i,
bend,
'ebendattrs', dbgname, dbggen, i, bend,
jsonb_build_object(
'adjsize', res.adjsize,
'baselinelength', res.baselinelength,
@ -406,9 +380,9 @@ begin
end;
$$ language plpgsql;
-- wm_exaggerate exaggerates a given bend. Must be a simple linestring.
drop function if exists wm_exaggerate;
create function wm_exaggerate(
-- wm_exaggerate_bend exaggerates a given bend. Must be a simple linestring.
drop function if exists wm_exaggerate_bend;
create function wm_exaggerate_bend(
INOUT bend geometry,
size float,
desired_size float
@ -457,8 +431,7 @@ begin
order by path[1], path[2]
));
bend = st_makeline(points);
bend = st_setsrid(st_makeline(points), st_srid(bend));
size = wm_adjsize(bend);
end loop;
end
@ -490,6 +463,7 @@ begin
end
$$ language plpgsql;
-- wm_exaggeration is the Exaggeration Operator described in the WM paper.
create function wm_exaggeration(
INOUT bendattrs wm_t_bend_attrs[],
dhalfcircle float,
@ -498,7 +472,45 @@ create function wm_exaggeration(
OUT mutated boolean
) as $$
declare
desired_size constant float default pi() * ((dhalfcircle/2)^2)/2;
tmpbendattr wm_t_bend_attrs;
i integer;
last_id integer;
begin
mutated = false;
for i in 1..array_length(bendattrs, 1) loop
if bendattrs[i].isolated and bendattrs[i].adjsize < desired_size then
mutated = true;
tmpbendattr.bend = wm_exaggerate_bend(
bendattrs[i].bend,
bendattrs[i].adjsize,
desired_size
);
bendattrs[i] = tmpbendattr;
-- remove last vertex of the previous bend and
-- first vertex of the next bend, because bends always
-- share a line segment together
-- this is duplicated in a few places, because PostGIS
-- does not allow (?) mutating an array when passed to a
-- function.
tmpbendattr.bend = st_removepoint(
bendattrs[i-1].bend,
st_npoints(bendattrs[i-1].bend)-1
);
bendattrs[i-1] = tmpbendattr;
tmpbendattr.bend = st_removepoint(bendattrs[i+1].bend, 0);
bendattrs[i+1] = tmpbendattr;
if dbgname is not null then
insert into wm_debug (stage, name, gen, nbend, way) values(
'gexaggeration', dbgname, dbggen, i, bendattrs[i].bend
);
end if;
end if;
end loop;
end
$$ language plpgsql;
@ -511,22 +523,21 @@ create function wm_elimination(
OUT mutated boolean
) as $$
declare
area_threshold float;
desired_size constant float default pi() * ((dhalfcircle/2)^2)/2;
leftsize float;
rightsize float;
i int4;
j int4;
tmpbendattrs wm_t_bend_attrs;
tmpbendattr wm_t_bend_attrs;
dbgbends geometry[];
begin
area_threshold = radians(180) * ((dhalfcircle/2)^2)/2;
mutated = false;
i = 1;
while i < array_length(bendattrs, 1)-1 loop
i = i + 1;
continue when bendattrs[i].adjsize = 0;
continue when bendattrs[i].adjsize > area_threshold;
continue when bendattrs[i].adjsize > desired_size;
if i = 2 then
leftsize = bendattrs[i].adjsize + 1;
@ -545,21 +556,21 @@ begin
-- Local minimum. Elminate bend!
mutated = true;
tmpbendattrs.bend = st_makeline(
tmpbendattr.bend = st_makeline(
st_pointn(bendattrs[i].bend, 1),
st_pointn(bendattrs[i].bend, -1)
);
bendattrs[i] = tmpbendattrs;
bendattrs[i] = tmpbendattr;
-- remove last vertex of the previous bend and
-- first vertex of the next bend, because bends always
-- share a line segment together
tmpbendattrs.bend = st_removepoint(
tmpbendattr.bend = st_removepoint(
bendattrs[i-1].bend,
st_npoints(bendattrs[i-1].bend)-1
);
bendattrs[i-1] = tmpbendattrs;
tmpbendattrs.bend = st_removepoint(bendattrs[i+1].bend, 0);
bendattrs[i+1] = tmpbendattrs;
bendattrs[i-1] = tmpbendattr;
tmpbendattr.bend = st_removepoint(bendattrs[i+1].bend, 0);
bendattrs[i+1] = tmpbendattr;
-- the next bend's adjsize is now messed up; it should not be taken
-- into consideration for other local minimas. Skip over 2.
i = i + 2;
@ -571,7 +582,7 @@ begin
end loop;
insert into wm_debug(stage, name, gen, nbend, way) values(
'felimination',
'helimination',
dbgname,
dbggen,
generate_subscripts(dbgbends, 1),
@ -593,8 +604,20 @@ declare
skip_next bool;
res wm_t_bend_attrs;
i int4;
last_id integer;
begin
for i in 2..array_length(bendattrs, 1)-1 loop
for i in 1..array_length(bendattrs, 1) loop
if dbgname is not null then
insert into wm_debug (stage, name, gen, nbend, way, props) values(
'fisolated_bends', dbgname, dbggen, i, bendattrs[i].bend,
jsonb_build_object('isolated', false)
) returning id into last_id;
end if;
-- first and last bends cannot be isolated
if i = 1 or i = array_length(bendattrs, 1) then
continue;
end if;
res = bendattrs[i];
if skip_next then
skip_next = false;
@ -605,24 +628,13 @@ begin
res.isolated = true;
bendattrs[i] = res;
skip_next = true;
end if;
end if;
if dbgname is not null then
insert into wm_debug (stage, name, gen, nbend, way, props) values(
'fisolated_bends',
dbgname,
dbggen,
i,
res.bend,
jsonb_build_object(
'area', res.area,
'adjsize', res.adjsize,
'baselinelength', res.baselinelength,
'curvature', res.curvature,
'isolated', res.isolated
)
);
if dbgname is not null then
update wm_debug
set props=props || jsonb_build_object('isolated', true)
where id=last_id;
end if;
end if;
end if;
end loop;
@ -680,6 +692,7 @@ declare
bendattrs wm_t_bend_attrs[];
mutated boolean;
l_type text;
dbggeoms geometry[];
begin
l_type = st_geometrytype(geom);
if l_type = 'ST_LineString' then
@ -711,24 +724,39 @@ begin
end if;
bendattrs = array((select wm_bend_attrs(bends, dbgname, gen)));
-- code to detect isolated bends is there, but bend exaggeration
-- is not implemented.
perform wm_isolated_bends(bendattrs, dbgname, gen);
bendattrs = wm_isolated_bends(bendattrs, dbgname, gen);
--select * from wm_exaggeration(
-- bendattrs, dhalfcircle, dbgname, gen) into bendattrs, mutated;
select * from wm_elimination(
bendattrs, dhalfcircle, dbgname, gen) into bendattrs, mutated;
-- TODO: wm_combination
if not mutated then
select * from wm_elimination(
bendattrs, dhalfcircle, dbgname, gen) into bendattrs, mutated;
end if;
if mutated then
for j in 1..array_length(bendattrs, 1) loop
bends[j] = bendattrs[j].bend;
end loop;
lines[i] = st_linemerge(st_union(bends));
gen = gen + 1;
continue;
if st_geometrytype(lines[i]) != 'ST_lineString' then
dbggeoms = array((select a.geom from st_dump(lines[i]) a order by path[1] asc));
insert into wm_debug (stage, name, gen, nbend, way) values(
'manual', dbgname, gen,
generate_subscripts(dbggeoms, 1),
unnest(dbggeoms)
);
raise notice '% non-linestring: %', dbgname, st_summary(lines[i]);
exit;
else
continue;
end if;
end if;
end loop;
end loop;