-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 01/04/15 15:40, Rachel Murphy wrote: > I have a townland that is split in two by a road (Ballysteena, Co > Tipperary). How do you handle this? Do you have to create two separate > areas/polygons and then combine somehow?
Hi Rachel, It's actually not that hard. You only create one townland relation, then add all the edges for the first part in as members, with the 'outer' role.... Then just add all the edges of the other part (again with 'outer')! Here's an example: http://www.openstreetmap.org/relation/3341134 You can see the little island to the south ( http://www.openstreetmap.org/way/4563271 ) is just added as another member of the townland relation with an "outer" role. When you do right it in JOSM, you should see 2 "loops" in the relation window (if you have 3 parts, 3 loops etc). The OSM wiki goes into more details: http://wiki.openstreetmap.org/wiki/Relation:multipolygon#Two_disjunct_outer_rings and http://wiki.openstreetmap.org/wiki/Relation:multipolygon#Two_disjunct_outer_rings_and_multiple_ways_forming_a_ring It's not very common for townlands (since they are so small), but you can often have civil parishes, baronies and counties made up of more than one bit (e.g. a civil parish: http://www.townlands.ie/clare/kilmacrehy/ ). County Galway, for example, is made up of the mainland, and the Aran Islands (and lots of other islands too). That is all mapped in this same way. The way it works under the hood is that software that does things with OSM data (e.g. to make a map) will try to join up all the edges together if they touch at an end. At the end of that process there might be one polygon, or many polygons. So it all works out. Hope that helps Rory -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQEcBAEBAgAGBQJVHAFjAAoJEOrWdmeZivv2njUH/2RcIfCgDthoDAnEbeBlTQmS akiNkbeOsaUfow0rpZNgL3zasEYNGXmTZy2ZnZ1dTCHvdw/e2VG+1SFj4DPWbkTr oVJtDiC0Lnwq50jgAXnkhep7jzvvpiwNj1RkvekT7+bYgjK1gLRxkhpaUMV4kQTs y8SVH3GPUHXWMTp6qG+Tt5Hc+GOM2oDaIR744IuoKv/aTkUw5JxxiMfOhUJu1EIU 5mYBg0cnorghcc1kJJ3pfsF+lijaOzRCzJ85WJyMFWCIfWBlKXIESpVDrLvlzWi0 TtGWVR4zaNVsuWrMxG0Bd0W9cJ5v1ZR0vtSX2xNL0Ra3fb5j+91XHXqBY/nk6uI= =YhMm -----END PGP SIGNATURE----- _______________________________________________ Talk-ie mailing list [email protected] https://lists.openstreetmap.org/listinfo/talk-ie
