[OSM-dev] RFC: OSM data format MIME types

[Jochen Topf]

On Thu, Sep 15, 2016 at 08:49:24AM +0200, Colin Smale wrote:
> Why the distinction for "historical"? The XML format is the same, isn't
> it? The "normal" version just limits itself to a single (the most
> recent) version - it a simple subset of "historical". 

There is one difference, the "visible" attribute is usually only
available in history files.

But the more important reason in my opinion is the use of those files is
different. A program that can read one type of file might not
necessarily cope with the other. And if it can, it might do different
things based on which type of file it is. I have been running into this
problem developing Osmium, that a program can't "just do the right
thing" if it doesn't know whether an input file is a normal data file or
a history file. (And there is no way to find out until you find the
first objects with multiple versions in there (which is not trivial to
find out if files are not sorted (which they don't have to be.)))

Jochen
-- 
Jochen Topf  jochen at remote.org  http://www.jochentopf.com/  +49-351-31778688