[OSM-dev] Various OSM troubles

Andy Robinson Andy_J_Robinson at blueyonder.co.uk
Sun Jan 7 09:47:12 GMT 2007


Christoph Eckert wrote:
>Sent: 06 January 2007 11:41 PM
>To: dev at openstreetmap.org
>Subject: [OSM-dev] Various OSM troubles
>

Christoph,

Hopefully I can give you an insight to these issues. Someone else may be
able to give you chapter and verse on any specifics.

>Hi,
>
>as a member of the osm talk list, I just subscribed to the devel list. I
>hope the following points are appropriate here; if not, please point me
>to a better location.
>
>I started mapping in late summer of 2006 and have contributed the first
>set of data for Karlsruhe, my home town. Meanwhile we are three mapping
>people here and therefore we have been able to map huge portions of
>Karlsruhe.
>
>Today I wanted to load the existing data as a map to my Garmin device
>using osmgarminmap contributed by User:Joto (also a cool piece of
>software BTW).
>
>I encountered some inconveniences and I wasn't able to find the exact
>reason, but if those were bugs I hope we are able to locate and fix
>them one day ("real soon no (TM)" :) .
>
>
>=== Getting a bigger area ===
>
>I desired to have the complete area I mapped on my GPS device to refine
>it. I tried to get the data of this area using JOSM. The coordinates
>(lat,lon) are
>48.28340621665376,7.588906762370101
>to
>49.77573536590515,8.915421561704648
>JOSM needs some time, then I get an error:
>Server returned HTTP response code: 500
>According to w3.org, this is a server error. This problem occured for
>some time now, so it surely is not a temporary problem. I can solve it
>by reducing the size of the area, but as it is the area my bicycle can
>reach easily from my home I'd enjoy having the hole area on my device.
>Is it an intentional error (preserving the server from denial of service
>attacks)? If so, was it possible to increase the default data size a
>bit?

This is most likely an SQL query timeout and has always been present to some
degree or other throughout the project to date. If we had tons more hardware
my guess is the project could deliver more data for each query. Until then
we must consider the workaround.

The temporary solution is to download the area in chunks into JOSM and then
save the whole lot as an .osm file to your hard disk. Close down JOSM and
then reload the same file again from the hard disk and you should find you
have a fully functioning enlarged area. (JOSM does not always handle joins
between partly downloaded data properly and hence the recommendation to
close JOSM and reload the file before working on it)

You can do the same via a direct call to the API using wget or similar.
Details for obtaining "map" data from the REST page on the wiki.

>
>=== Download of incomplete objects ===
>
>I took a smaller area and converted it successfully for my garmin
>device. Unfortunately some weird red lines are crossing the map. I
>guessed those are caused by ways which haven't been downloaded
>completely, due to the bounding box specified. So I simply selected all
>downloaded data in JOSM and tried >Download incomplete objects<. The
>progress bar appeard to download 34 items, but neither it disappeared
>nor data got downloaded. After some time, I pressed cancel as it was
>obvious that it took to long.
>I just tried it again with the village where I was born. Only two
>segments had to be downloaded, but it took several minutes.
>I have no clue if it is a server or a client problem, but are there
>chances to speed this process up?
>

This seems to be a problem that's been occurring over the last week. Queries
involving ways have historically always taken a lot longer to process than
node or segment queries but the current wait is I agree unacceptable. If you
leave it running and go and have a cup of tea then generally you will find
it eventually returns. The call for each way is separate and sequential so
for one or two it may not take very long but for numerous the wait at the
moment is very very long.


>=== Slippy map search ===
>
>Finally a minor issue. I used the slippy maps today to view the data of
>the Karlsruhe area and I was pretty impressed, so thanks to all
>involved. I found a minor issue. Above the map, there's a search line
>edit, so I entered >Karlsruhe< just for fun. Surprisingly, it returned
>two entries, the Rheinhafen Karlsruhe (which actually is a waterway)
>and the railway Karlsruhe-Rastatt. There's nothing wrong with that, but
>I missed the node tagged as
>place=city
>name=Karlsruhe
>which also exists in the database.
>
>Visitors of our web pages might use the line edit to search for their
>hometown first, so I think it would be cool to include nodes tagged
>with "place" in the search.

Currently the best way to search for a place is to click on the "city
search" which is returned at the top of the page after the initial search
results. The city search uses the geonames database rather than the results
of metadata in the OSM database. When someone has some coding time to devote
to improving the search capabilities I'm sure it will get much better.
Currently it was only taken to a simple first implementation level. 


>
>Thanks & best regards,
>
>ce
>

Of course most of these issues require more coding or hardware, both of
which are in very short supply. You are probably the first person to sign up
to the dev list in a very long time, so welcome. Anything you or others can
do to contribute on the development side will be appreciated by all.

Cheers

Andy

Andy Robinson
Andy_J_Robinson at blueyonder.co.uk


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