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Overpass query to find multipolygon relations with just one member

I hacked at this OverPass Wiki example to find multi-polygon relations with just one member. The resulting routine seems to work but looks like it is running unnecessary steps. I've run out of knowledge. Is there anything I can do to tidy it up & make it run more efficiently?

rel({{bbox}})[type=multipolygon]->.relations;
foreach .relations -> .relation (
  (
   way(r.relation);
  )->.elem_all;

  rel.relation( if:elem_all.count(ways) == 1 );
  out geom;
);

OverpassTurbo Link

member overpass relations multipolygon

asked 19 Mar '18, 21:13

DaveF
3.3k●84●98●133
accept rate: 16%

One Answer:

There's a count_members evaluator that looks inside of each individual relation:

[bbox:{{bbox}}];
rel[type=multipolygon](if:count_members() == 1);
out geom;

http://overpass-turbo.eu/s/x9L

answered 20 Mar '18, 00:32

maxerickson
12.7k●10●83●176
accept rate: 32%

Ah, thank you. my Google search 'overpass count' wasn't specific enough to find it.

(20 Mar '18, 14:45) DaveF