[OSM-talk] Converting Polish/.MP to OSM?

[Karl Newman]

On Tue, May 13, 2008 at 12:08 AM, Simon Wood <simon at mungewell.org> wrote:

> On Fri, 9 May 2008 00:24:11 -0600
> Simon Wood <simon at mungewell.org> wrote:
>
> > Well I've had a stab at this, probably the worlds worst python script but
> it does work....
>
> Cleaned up version added to SVN, browsable here:
>
> http://trac.openstreetmap.org/browser/applications/utils/import/mp2osm/mp2osm_catmp.py
>
> Supports POI, POLYLINE and POLYGON. Can parse the CATMP stuff without
> error, but have not uploaded resultant data to OSM yet. Doesn't do anything
> with the 'Nod[1..]' bits as I couldn't see how to re-open an element in
> ElementTree to modify it/add the appropriate tag.
>
> Cheers,
> Mungewell.
>

Simon,

Okay, I finally got around to taking a quick look at your script and your
converted data. I don't really know python, but I have a few comments:
1. This import doesn't keep track of the topology (i.e., nodes are
duplicated instead of shared between ways which connect). For a nice,
routable dataset such as what we're getting here, it would be a shame to
lose that. Maybe you could create a hashtable with a mapping from the
routing nodes (Nod[1...]) to the OSM node ids, and then refer to that as
you're creating the ways (and re-use the OSM ids when you encounter a
routing Node ID you've seen before). You might want to just read the entire
Data0 line into a string variable and then defer parsing it until you hit
the [END] line for that section.
2. You should only be reading the Data0 info, because it has the
highest-resolution data (what we want to import). The higher numbers just
have lower-resolution data for farther-out zoom. If I'm reading it right, it
looks like you're appending all the linestrings from each Data0, Data1, etc.
together, which will create a repeated, overlapping series, which is not
what you want.
3. It wouldn't take much to explode the "RouteParam" line and assign access,
oneway and maxspeed tags to the ways based on that information. I gave you
the explanation of the encoding of the RouteParam fields in an earlier
email.
4. Similarly, there should be only a few Garmin map types used in this
map--it wouldn't take much to translate those to OSM "highway" or whatever
tags.

There are a bunch of map datasets out there being maintained in the MP or
Polish map format, so spending some time to get this script improved could
have a great impact later if we get to import some of those other ones. If I
get a chance this weekend (not very likely), I'll see if I can improve the
script, but if you get to it first, so much the better.

Karl
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/talk/attachments/20080516/b9f4adf0/attachment.html>