[Talk-ca] OSM Geobase import: giving a try
Frank Steggink
steggink at steggink.org
Sun Feb 15 17:34:05 GMT 2009
Hi,
I've sent below mail to Michel, who I met at the Sherbrooke mapping party last
year, but I presume he's quite busy, so I'm posting it here.
I haven't really been following the talk-ca mailing list, but I would like to
give it a try. I don't know yet how much time and energy I'm willing to spend.
That usually comes in big lapses, just like my OSM contributions :)
I've tried to digest the wiki pages and e-mails, but it's quite a lot of
information. It is especially hard to identify what information is still current
and what is obsolete. Hopefully you can help me getting started by answering a
couple of questions. I understand that the NRN data has the highest priority, so
I'll focus on that.
1. Is there an agreed set of tags which need to be imported? There
Geobase_NRN_-_OSM_Map_Feature page on the wiki lists a huge list of tags. Should
they all be converted? I assume we would like to keep the imported data
consistent, although there will be differences between different provinces, and
existing data will also be different.
a. What is the final resolution about NID's? Do they need to be kept?
b. How can we guarantee that the final import will be consistent? (See also
my first question.)
2. Do I have to use existing software / processes, like RoadMatcher, or can I
develop a way to import data in a way that will suit me the most?
a. For software it makes most sense to reuse what is already available, and
adjust it when necessary.
b. I'm actually missing a best practice page. It is not evident what the
most efficient process is, but that's also likely subject to personal taste /
skills.
3. Is there an existing tool to cut the NRN data files in tiles? Or does someone
host the NRN data which are already cut into tiles? Or is it preferred to use
the Ibycus topo maps (and convert them to OSM)?
a. Do the Ibycus maps contain all attributes? I don't think so, since
they're created specifically to be used by GPSs.
4. Since it seems there are several different individual import /
experimentation processes going on, many imports will have to be rolled back.
(I'll create a new OSM user, so my changes will be easily detectable.) Is there
a test server available?
[Not in the mail to Michel:]
Based on the gathered information I've developed a workflow based on PostGIS. I
still need to test it, but if this workflow is useful, I'll share it with you.
It will involve a certain degree of manual checks, but my experience is that
data imports always need close attention. It is very easy to mess up things. We
also need to take things like relationships into account.
That's about it for now. As a test area I'll probably use an area in the Beauce.
Sheet 021L07 seems to be a good candidate. I've mapped most of the existing OSM
roads, and there are some larger residential areas, but not too much.
Regards and thanks in advance,
Frank
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