[OSM-dev] Timestamp in PBF files

Frederik Ramm frederik at remote.org
Tue Dec 11 19:39:17 GMT 2012


Hi,

On 11.12.2012 16:29, Jochen Topf wrote:
> For starters this makes XML and PBF files incompatible which is
> not good.

They are already incompatible with regard to header fields; the XML 
files emitted by the API have "copyright", "attribution", and "license" 
header fields which PBF doesn't have as far as I can see.

It would be fairly trivial to add the new replication fields to an XML 
file if one so desired. Since nobody parses OSM XML with a schema 
anyway, unknown attributes would just be ignored.

 > Next it has to be figured out what changes to the input data lead to
 > changes in the output of these flags. Obviously when you apply a diff 
those
 > headers should change, shouldn't they? Those things all have to be 
figured out
 > and implemented properly.

This is not something that has to be implemented in Osmium, but by 
whoever uses Osmium to write a program with it. Today, Osmium supports a 
"bbox" header, and obviously if I write a program that does spatial 
filtering then this header has to change - but that is my responsibility 
and Osmium cannot be expected to do anything with that header 
automatically. It's exactly the same with the new replication headers.

(And there is much less documentation about what an application 
developer is expected to do with the "bbox" and "writingprogram" fields 
- and the additional "source" field which is defined in the PBF but not 
exposed by Osmium - than there is for the new replication fields, here 
http://wiki.openstreetmap.org/wiki/PBF.)

Bye
Frederik

-- 
Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"



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