Hi Lorenzo, my understanding of the fields with ??: - I think the version column was explained already. The combination of the version and the *_id together with the type (Node, Way,Relation) builds the uniquie id which identifies an object. So, you can have a way with id 2 and version 4 and a node with id 2 and version 4, but you cannot have two different nodes with id 2 and version 4. - The sequence_id is needed to be able to restore the order of referenced objects. - The timestamp fields probably contain the timestamp at which the object (version+id) was added to the database, but may also be the timestamp at which the changeset was closed. - num_changes : not sure, but I think it should be the number of changed or added objects in one changeset
Gerd ________________________________________ Von: Lorenzo Stucchi <lorenzostucch...@outlook.it> Gesendet: Donnerstag, 9. Januar 2020 11:29 An: dev@openstreetmap.org Betreff: Re: [OSM-dev] OSM Database schema Dear all, After the discussion that I started about the database schema I tried to create a wiki page that explains it, I started the page on my user wiki-page [1]. I started with few tables, but some elements present in the tables are not so clear to me. So If you wanna try to contribute to that page, since a description of the database can be provided to everyone. I will continue to modify it ,trying to understand all the tables. Thanks to everyone that will help, or just make a suggestion about it. Best, Lorenzo [1] https://wiki.openstreetmap.org/wiki/User:LorenzoStucchi/Description_DatabaseSchema Il giorno 4 gen 2020, alle ore 23:01, Martin Koppenhoefer <dieterdre...@gmail.com<mailto:dieterdre...@gmail.com>> ha scritto: sent from a phone On 4. Jan 2020, at 17:28, Jean Marie Falisse <fa003...@skynet.be<mailto:fa003...@skynet.be>> wrote: Is it still true that in the OSM database, areas are not represented as such? areas can be represented as areas through multipolygon relations which are always areas or by help of an additional tag (area=yes/no), or through plausibility (tags and their combinations may imply an area or not). There isn’t a dedicated area object, maybe this is what you meant. Areas are represented with ways, and tags or relations are required to define the ways as areas. That would mean, for instance, that a pedestrian zone, let’s say a big square in a city, cannot be made to be crossed diagonally when used in a route planner. Am I right? typically routing engines operate on graphs, i.e. they do not route diagonally across areas, but this isn’t related to the question whether there is a dedicated datatype for areas or not. Cheers Martin _______________________________________________ dev mailing list dev@openstreetmap.org<mailto:dev@openstreetmap.org> https://lists.openstreetmap.org/listinfo/dev _______________________________________________ dev mailing list dev@openstreetmap.org https://lists.openstreetmap.org/listinfo/dev
