Permanent ID: Unterschied zwischen den Versionen

Version vom 4. April 2019, 23:54 Uhr

This is an unofficial proposal for a "permanent ID" for OpenStreetMap (OSM).

The goal is to get an opaque fixed length ASCII string. And 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 geometry does not increment the version number.

So a stable Permanent ID could have the following form (which leads to a fixed length string of 35 chars in total):

 [N|W|R]<osm_id>#<version>[+|-]<lon>[+|-]<lat>

where:

N,W,R stands for Node, Way, or Relation.
osm_id is left-padded with zeros to get 10 chars ("digits").
version is 4 digits left padded with zeros.
coordinates have 5 fixed decimal places (lat is 2 and lon is 3 digits wide, both are signed and left-padded with zeros).

Example: "Schloss Kyburg" (Castle Kyburg) has relation 1169711, version #5 at coordinates 47.4584, 8.74343 which becomes following Permanent ID:

 R0001169711#0005+47.45840+008.74343

@@ Zeile 15: / Zeile 15: @@
 where:
 * N,W,R stands for Node, Way, or Relation.
-* osm_id is left-padded with zeros to get 10 chars ("digits"),
+* osm_id is left-padded with zeros to get 10 chars ("digits").
-* version is 4 zero-padded digits
+* version is 4 digits left padded with zeros.
-* coordinates have 5 fixed decimal places (lat is 2 and lon is 3 decimal places, both signed and left-padded with zeros).
+* coordinates have 5 fixed decimal places (lat is 2 and lon is 3 digits wide, both are signed and left-padded with zeros).
 Example: "Schloss Kyburg" (Castle Kyburg) has relation 1169711,