Permanent ID for OSM: Unterschied zwischen den Versionen
Stefan (Diskussion | Beiträge) (Die Seite wurde neu angelegt: « This is an '''unofficial proposal for a "permanent ID" (osm_pid) for OpenStreetMap (OSM)'''. See https://wiki.openstreetmap.org/wiki/Permanent_ID for a m…») |
Stefan (Diskussion | Beiträge) K |
||
| Zeile 1: | Zeile 1: | ||
This is an '''unofficial proposal for a "permanent ID" (osm_pid) for OpenStreetMap ([[OSM]])'''. | This is an '''unofficial proposal for a "permanent ID" (osm_pid) for OpenStreetMap ([[OSM]])'''. | ||
| − | + | === Goals and Requirements === | |
| − | + | The goal is to get an opaque (eventually fixed) length ASCII string. | |
| − | The goal is to get an opaque fixed length ASCII string. | ||
| + | That are the design considerations: | ||
* The OSM id alone is not stable enough (as probably most agree); and it can represent many concepts (and that's by design in OSM). | * The OSM id alone is not stable enough (as probably most agree); and it can represent many concepts (and that's by design in OSM). | ||
* The version no. of the object is needed which makes clear which tags are (or have been) referred to. | * The version no. of the object is needed which makes clear which tags are (or have been) referred to. | ||
* Coordinates are needed, because a change of the way and area geometries does not increment the version number. | * Coordinates are needed, because a change of the way and area geometries does not increment the version number. | ||
| − | + | === Format === | |
| + | |||
| + | A stable Permanent ID could have the following form (variable length to a maximum of currently 35 chars): | ||
[N|W|R]<osm_id>#<version>[+|-]<lon>[+|-]<lat> | [N|W|R]<osm_id>#<version>[+|-]<lon>[+|-]<lat> | ||
| Zeile 23: | Zeile 25: | ||
osm_pid = R1169711#5+47.4584+8.74343 | osm_pid = R1169711#5+47.4584+8.74343 | ||
| − | Service | + | === OSM Permanent ID Service === |
| + | |||
| + | In order to be really useful, a service should be implemented, which returns most recent object given a possibly old Permanent ID if an object has been changed; thus having another Permanent ID where any of it's parts may have changed (most probably just the version no.). | ||
| + | |||
| + | |||
| + | == Alternatives == | ||
| + | |||
| + | See https://wiki.openstreetmap.org/wiki/Permanent_ID for a more official state of discussions. | ||
| + | |||
| + | '''Use OSM id nevertheless (at own risk)''': ...as is with two fields type (Node, Way, Relation) and osm_id (bigint)... or as a '''single big integer'''. It's possible to encode the type (Node, Way, Relation) into the OSM id as a single integer (64 bit): osm_id = <node id> × 10 (eg. 123 → 1230), osm_id = (<way id> × 10) + 1 (eg. 123 → 1231), osm_id (<relation id> × 10) + 4 (eg. 123 → 1234). (Source: Mapbox, see [https://docs.mapbox.com/vector-tiles/reference/mapbox-streets-v8/#openstreetmap-ids]). Example: "Schloss Kyburg" is a relation with id 1169711, so it becomes 11697114. | ||
| − | + | '''OpenLR''' (Location Referencing) a free spec. by TomTom for linear geometries like streets [http://www.openlr.org/]. | |
Version vom 20. Juni 2019, 07:30 Uhr
This is an unofficial proposal for a "permanent ID" (osm_pid) for OpenStreetMap (OSM).
Inhaltsverzeichnis
Goals and Requirements
The goal is to get an opaque (eventually fixed) length ASCII string.
That are the design considerations:
- The OSM id alone is not stable enough (as probably most agree); and it can represent many concepts (and that's by design in OSM).
- The version no. of the object is needed which makes clear which tags are (or have been) referred to.
- Coordinates are needed, because a change of the way and area geometries does not increment the version number.
Format
A stable Permanent ID could have the following form (variable length to a maximum of currently 35 chars):
[N|W|R]<osm_id>#<version>[+|-]<lon>[+|-]<lat>
where:
- N,W,R stands for Node, Way, or Relation.
- osm_id an unsigned big integer ("digits").
- version is an unsigned integer with a hash in front.
- coordinates (lat/lon) are signed floats (always showing the +/- sign), with a maximum of 6 digits. In case of a line (linestring) or an area/relation (polygon) geometries the coordinates taken into account are the lat/lon minimum of the geometry.
Example: "Schloss Kyburg" (Castle Kyburg) has relation 1169711, version #5 at coordinates 47.4584, 8.74343 which becomes following Permanent ID:
osm_pid = R1169711#5+47.4584+8.74343
OSM Permanent ID Service
In order to be really useful, a service should be implemented, which returns most recent object given a possibly old Permanent ID if an object has been changed; thus having another Permanent ID where any of it's parts may have changed (most probably just the version no.).
Alternatives
See https://wiki.openstreetmap.org/wiki/Permanent_ID for a more official state of discussions.
Use OSM id nevertheless (at own risk): ...as is with two fields type (Node, Way, Relation) and osm_id (bigint)... or as a single big integer. It's possible to encode the type (Node, Way, Relation) into the OSM id as a single integer (64 bit): osm_id = <node id> × 10 (eg. 123 → 1230), osm_id = (<way id> × 10) + 1 (eg. 123 → 1231), osm_id (<relation id> × 10) + 4 (eg. 123 → 1234). (Source: Mapbox, see [1]). Example: "Schloss Kyburg" is a relation with id 1169711, so it becomes 11697114.
OpenLR (Location Referencing) a free spec. by TomTom for linear geometries like streets [2].
