Hi, i have just started working with OSMChange files ".osc" and after reading https://wiki.openstreetmap.org/wiki/OsmChange i still have some questions. In particular about the modify way and how to interpret it.

For example in this case alt text

What is this saying? That way 377346605 after the update will have 2 nodes and 1 tag? Or could there be an incremental update? For example way 377346605 after the update will have all the previous nodes plus the two listed in the xml?

I guess the question is if in general in this file format a modified way is always completely described? (In the case where the update is about deleting 1 node from a way made of 20, in the osc i would get all the 19 nodes listed with their ids)

If you have any link to this format documentation would be great. Thanks for the help, Federico.

asked 29 Nov '20, 18:27

Federico's gravatar image

Federico
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Not an answer to the question, but if you want to experiment with this on the development server, you can - see https://wiki.openstreetmap.org/wiki/Sandbox_for_editing .

(29 Nov '20, 18:30) SomeoneElse ♦

Thanks, i'll definitely give it a try. Best.

(29 Nov '20, 18:41) Federico

The change file contains the new complete version of all objects that changed. So in the example you mentioned there was a way 377346605 version 1, which we don't get any information about whatsoever. What we get is all information about version 2 of this way. So, yes, it references two nodes and has one tag now.

You don't get anything about any objects that didn't change themselves, even if they are referenced by changed objects. So you will not get node 3051449243 in the change file or node X that was in version 1 of the way but isn't any more, unless those nodes themselves changed. Generally this means that change files aren't very useful without an OSM file, database, or something like it that has all the objects.

permanent link

answered 30 Nov '20, 08:16

Jochen%20Topf's gravatar image

Jochen Topf
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accept rate: 31%

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question asked: 29 Nov '20, 18:27

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last updated: 30 Nov '20, 08:16

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