[OSM-dev] OSM XML declaration, JOSM, Osmosis et al.

Roland Olbricht roland.olbricht at gmx.de
Thu Sep 22 05:37:57 BST 2011


> Is Overpass so geared for tools that don't care about
> uid/date/version/visible etc?

Actually, yes. Note that these tools include map rendering, routing, location 
based search and probably every other tool that consumes the data. The data 
model is: the state of the Planet database (or an excerpt) at a fixed point in 
time, which makes perfectly sense.

Even keeping a database up to date would be possible without meta data: It 
suffices to know the timestamp of the patches as a whole, not of every 
individual element, despite the behaviour of possibly picky tools.

The old XAPI had mainly been suffering from a permanent shortage of hardware 
resources. You now get a switch to download data three times faster if you 
omit data that you discard anyway later  - if you render a map, do routing, or 
a lot of other useful things. This would even lower the burden on the still 
hardware-constrained Overpass API server. A lot of users encounter that useful 
but some can't make sense of the error messages somewhere later in the tool 
chain. I can't and I won't rewrite every tool, but I can happily write in the 
header whatever the tools expect. I simply asking for a consensus for the 
things to write in the header.

Discussing the usefulness of the current history model is a different 
question. As I got never an answer to an earlier post on that topic,
http://lists.openstreetmap.org/pipermail/talk/2011-September/060027.html
I assume that history is only a minor concern to most users.

Cheers,

Roland



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