Support for importing non-area relations as MultiLineString

[talaj]

trafficstars

It can be convenient to be able to import non-area relations as MultiLineString geometries into linestring table.

This PR adds this capability. Only relations specified in relation_types will be imported. No relations are imported by default.

[olt]

Hi. Thanks for your PR.

The timing is a bit unfortunate as I just made a larger refactoring. Parsing and some basic stuff is moved into a separate library (https://github.com/omniscale/go-osm). The changes are the go-osm branch (https://github.com/omniscale/imposm3/tree/go-osm).

Can you base your patch on this branch and see if you need to make any changes?

For tests: It's great that you included a new system test. But can your use short and commented dummy OSM files like https://github.com/omniscale/imposm3/blob/go-osm/test/route_relation.osm and https://github.com/omniscale/imposm3/blob/go-osm/test/route_relation.osc

[talaj]

Hi @olt. I've rebased it on top of go-osm branch. There were just minor conflicts. The OSM files should be more comprehensible now.

[komackaj]

@olt Any chance of this being merged? Would be super-useful for me.

[talaj]

I've rebased it on top of master and changed the base branch to master. Surprisingly, there was no conflict after those two years.

[farfromrefug]

@olt I am in the need for that PR. Any reason why it is left unmerged?

[olt]

Sorry for the long silence. Is my understanding correct, that this change is backward incompatible with older imports? (It will try to import multipolygons into linestring tables?)

Can someone who used this patch comment on that?