Re: [OSM-dev] Difference between osm and osmChange formats
Am 01.06.2011 19:29, schrieb Sergey Galuzo: As far as special format for diffs... Why do we have it as opposed just to using full history format for diffs? Same data... Do-o-crathy. Some one wrote a full-history dumper and now we have the full-history format. Someone else wrote the minutely-diff-thing and now we have a diff-file-format. Peter ___ dev mailing list dev@openstreetmap.org http://lists.openstreetmap.org/listinfo/dev
Re: [OSM-dev] Difference between osm and osmChange formats
Am 31.05.2011 23:43, schrieb Sergey Galuzo: varchangeTag = !Visible ? delete : Version == 1 ? create : modify; This may be true when you look at an object's complete history. But don't let you confuse from the similar syntax of .osm and .osc files -- they represent very different things. It's like comparing a .cpp-file with a .patch-file -- you can produce one out of the other but despite that they have not many things common. Peter ___ dev mailing list dev@openstreetmap.org http://lists.openstreetmap.org/listinfo/dev
Re: [OSM-dev] Difference between osm and osmChange formats
On 1 June 2011 17:51, Peter Körner osm-li...@mazdermind.de wrote: Am 31.05.2011 23:43, schrieb Sergey Galuzo: varchangeTag = !Visible ? delete : Version == 1 ? create : modify; This may be true when you look at an object's complete history. But don't let you confuse from the similar syntax of .osm and .osc files -- they represent very different things. The original poster had it mostly correct, they are almost identical expect for the create/modify/delete tags and the osc file uses osmChange instead of osm ___ dev mailing list dev@openstreetmap.org http://lists.openstreetmap.org/listinfo/dev
Re: [OSM-dev] Difference between osm and osmChange formats
Hi, On 05/31/11 23:43, Sergey Galuzo wrote: Obvious differences between full and change are explicit create/modify/delete tags. We have full history OSM files and normal OSM files (both use .osm extension and osm.../osm), and we have simple diffs and replication diffs (both use .osc and osmChange.../osmChange). Normal OSM files never have a visible attribute, and they contain at most one version of every object. Objects in full history OSM files contain a visible attribute, and these files may contain different versions of the same object, with at most one having visible=true. If there is a version with visible=true, it will be the highest numbered version of that object. They do not necessarily contain a full sequence of versions, i.e. you could have a full history file that only has versions 2 and 5 of something. (There are also .osm files as written by the JOSM editor; these do not have a visible attribute but may have an action attribute which, if set to delete, has a similar effect. This is a niche case.) The diffs contain delete, modify, and create blocks. A version in create is usually 1. (Current implementation means it is *always* 1 but this could be changed; it is not specified in the API that the first version of something must always be 1.) A version in create or modify can never have visible=false. If you have full replication diffs then one diff can contain the same object multiple times, with different version numbers. It is possible for the same object to appear in the create, modify, and delete section of the same replication diff. Versions are not guaranteed to be sorted, i.e. you could first encounter version 6 in a delete block and later encounter version 5 in a modify. Since multiple edits are conflated in a simple diff, it is possible that a simple diff contains an object as version 2 in a modify block but the consumer has never before seen that object (because the version 1 that would have been in a create has happened in the same diff interval as the modification to version 2). In short, your assumption var changeTag = !Visible ? delete : Version == 1 ? create : modify; is mostly true but it depends very much on the context in which you want to use it; there's a lot of things to trip you over. Bye Frederik ___ dev mailing list dev@openstreetmap.org http://lists.openstreetmap.org/listinfo/dev
Re: [OSM-dev] Difference between osm and osmChange formats
On Wed, Jun 1, 2011 at 2:34 PM, Frederik Ramm frede...@remote.org wrote: We have full history OSM files and normal OSM files (both use .osm extension and osm.../osm), and we have simple diffs and replication diffs (both use .osc and osmChange.../osmChange). Normal OSM files never have a visible attribute, and they contain at most one version of every object. Not quite true - API map calls return normal OSM files with the visible attribute set. Objects in full history OSM files contain a visible attribute, and these files may contain different versions of the same object, with at most one having visible=true. Again, not quite true - full history files returned by the api history calls contain different versions of the same object, where many versions can be shown with the visible=true attribute. Perhaps it could be summarised as There are many different pieces of software generating both normal and full-history OSM files, and simple and replication diffs, and the visible attribute may or may not appear in any of them. :-) Cheers, Andy ___ dev mailing list dev@openstreetmap.org http://lists.openstreetmap.org/listinfo/dev
Re: [OSM-dev] Difference between osm and osmChange formats
Thanks for excellent info. As far as special format for diffs... Why do we have it as opposed just to using full history format for diffs? Same data... Thanks, Sergey. -Original Message- From: Frederik Ramm [mailto:frede...@remote.org] Sent: Wednesday, June 01, 2011 6:34 AM To: dev@openstreetmap.org Subject: Re: [OSM-dev] Difference between osm and osmChange formats Hi, On 05/31/11 23:43, Sergey Galuzo wrote: Obvious differences between full and change are explicit create/modify/delete tags. We have full history OSM files and normal OSM files (both use .osm extension and osm.../osm), and we have simple diffs and replication diffs (both use .osc and osmChange.../osmChange). Normal OSM files never have a visible attribute, and they contain at most one version of every object. Objects in full history OSM files contain a visible attribute, and these files may contain different versions of the same object, with at most one having visible=true. If there is a version with visible=true, it will be the highest numbered version of that object. They do not necessarily contain a full sequence of versions, i.e. you could have a full history file that only has versions 2 and 5 of something. (There are also .osm files as written by the JOSM editor; these do not have a visible attribute but may have an action attribute which, if set to delete, has a similar effect. This is a niche case.) The diffs contain delete, modify, and create blocks. A version in create is usually 1. (Current implementation means it is *always* 1 but this could be changed; it is not specified in the API that the first version of something must always be 1.) A version in create or modify can never have visible=false. If you have full replication diffs then one diff can contain the same object multiple times, with different version numbers. It is possible for the same object to appear in the create, modify, and delete section of the same replication diff. Versions are not guaranteed to be sorted, i.e. you could first encounter version 6 in a delete block and later encounter version 5 in a modify. Since multiple edits are conflated in a simple diff, it is possible that a simple diff contains an object as version 2 in a modify block but the consumer has never before seen that object (because the version 1 that would have been in a create has happened in the same diff interval as the modification to version 2). In short, your assumption var changeTag = !Visible ? delete : Version == 1 ? create : modify; is mostly true but it depends very much on the context in which you want to use it; there's a lot of things to trip you over. Bye Frederik ___ dev mailing list dev@openstreetmap.org http://lists.openstreetmap.org/listinfo/dev ___ dev mailing list dev@openstreetmap.org http://lists.openstreetmap.org/listinfo/dev
Re: [OSM-dev] Difference between osm and osmChange formats
hi there Sergey, well yes OSM has different XML 'flavours' but AFAIK osmChange doesnt contain the Visible attribute. This is used by editors as JOSM as a flag for removed objects. A good comparision is this page: http://wiki.openstreetmap.org/wiki/XML bye Matthias ___ dev mailing list dev@openstreetmap.org http://lists.openstreetmap.org/listinfo/dev
