OpenStreetMap

The Java XAPI

Posted by iandees on 26 January 2011 in English (English)

I recently released the first version of a mostly-complete Java implementation of the XAPI server. The source code is available on my GitHub with a readme describing generally how to get it set up.

Running this database with a full-planet requires some large, fast disks. The database is roughly 350GB and is slowly increasing:

CPU and memory usage are useful for the initial import (indexing especially), but any subsequent queries will be limited by the disk speed.

Feel free to use it! Serge W. created an XAPI UI framework that I set up at http://openstreetmap.us/uixapi/xapi.html to build the XAPI query URLs.

At the moment, the Java XAPI seems to have a problem returning relations and doesn't implement child element predicates or special tags. If you find other problems, please file a bug.

Comment from Firefishy on 26 January 2011 at 15:13

Stats for xapi.osm.org for 25 Jan 2011:
tags:
@user= - 27 queries from 12 IP addresses.
@uid= - 3 queries from 2 IP address.
@changeset - 1 query

Hide this comment

Comment from Harry Wood on 26 January 2011 at 16:00

You didn't actually mention the base URL for your new service: http://openstreetmap.us/xapi/api/0.6/

It works! Example: All the libraries in London : http://openstreetmap.us/xapi/api/0.6/*[amenity=library][bbox=-0.57,51.24,0.31,51.75]

Great work!

Hide this comment

Comment from Tom Chance on 26 January 2011 at 16:24

Great, I'll give it a go.

Hide this comment

Comment from Maarten Deen on 26 January 2011 at 16:37

Looks promising. But the performance with large bboxes isn't there yet.
Harry Wood's example works for me, I can also download banks in a 0.2x0.2 bbox, but trying to get banks for the whole of the Netherlands does not work yet. I get a "504 Gateway Time-out" message.
My test URL: http://openstreetmap.us/xapi/api/0.6/*[amenity=bank][bbox=2.5,50.7,7.2,53.6]

Hide this comment

Comment from iandees on 26 January 2011 at 16:42

The machine restarted itself at 16:00UTC or so, which lines itself up with your request fairly well.

But yes, large bounding box queries are mildly slow -- I don't remember them being particularly fast on the other system, though.

Hide this comment

Comment from Tom Chance on 26 January 2011 at 16:48

I get the same message trying to download all power generators in the UK.

http://openstreetmap.us/xapi/api/0.6/*[power=generator][-6.5,49.68,2.67,61.31]

Just London works fine:
http://openstreetmap.us/xapi/api/0.6/*[power=generator][bbox=-0.5
1,51.20,0.35,51.80]

Hide this comment

Comment from iandees on 26 January 2011 at 16:53

It bounced a few more times and is down hard now. There appear to be some ECC memory errors, but I put fresh memory in a while back. Looks to be a bad motherboard. Thanks for the stress test, everyone!

Hide this comment

Comment from Geonick on 27 January 2011 at 23:13

Is this XAPI UI really reflect the syntax of XAPI? Currently there is only one tag predicate. Isn't it possible to query more than one, like

http://openstreetmap.us/xapi/api/0.6/*[amenity=parking][capacity:disabled=*][bbox=-0.57,51.24,0.31,51.75]

Actually, even the OSM wiki leaves this question open:
http://wiki.openstreetmap.org/wiki/Xapi#Predicates

It would be nice anyhow that the wiki page get's enhanced with a real syntax definition.

Hide this comment

Comment from iandees on 28 January 2011 at 01:24

@Geonick: yes, this really does follow the XAPI query syntax. You can indeed supply multiple tag predicates. It will eventually be possible to include multiple bounding box predicates, but at the moment I only allow one.

Hide this comment

Comment from Katzman on 9 March 2011 at 21:01

Two things:
- so the possibility to enter multiple tags is not implemented yet, right?
- is it possible to do non-case sensitive search on the values, such as icao=lklt would return any combination of LKLT, lklt, LKlt, LkLt, etc.?

Thanks!

Hide this comment

Comment from iandees on 9 March 2011 at 21:03

@Katzman:

1. It is possible to enter multiple tag predicates:

[amenity=foo|bar] := "amenity"="foo" OR "amenity"="bar"
[amenity|leisure=foo] := "amenity"="foo" OR "leisure"="foo"
[amenity=foo][area=bar] := "amenity"="foo" AND "area"="bar"

2. Not at this time.

Hide this comment

Comment from Arminus on 21 March 2011 at 19:34

Very nice ! Any updates on the relation problem ?

Hide this comment

Comment from Tilo on 31 March 2011 at 17:45

Is the jxapi down at the moment?

I want to prevent denied download requests before the request is sent. How is it handled, if a bbox is too large? like this?
[bbox=West,South,East,North]
if difference(West,East)*difference(South,North) > 10 --> denied
if difference(West,East)*difference(South,North) accepted

Is it planned to allow larger bboxes than 10 sqaredegrees in future?

Thanks!

Hide this comment

Comment from Tilo on 31 March 2011 at 17:48

[bbox=West,South,East,North]
if difference(West,East)*difference(South,North) > 10 --- denied
if difference(West,East)*difference(South,North)

Hide this comment

Comment from iandees on 31 March 2011 at 17:51

@Tilo: No, the jxapi is/was not down. It was getting inundated with duplicate requests so the process queue was very long. I restarted postgres to clean out the queue.

I compute the sum of the areas of the requested bounding box(es) and compare that to 10. If larger, 500. If less, let it through.

There are no plans to do areas larger than 10 square degrees. As you can see already the hardware has a hard enough time keeping up.

Hide this comment

Comment from Tilo on 31 March 2011 at 17:51

damn,
the third line was supposed to look like this (now, in words):
if difference(West,East)*difference(South,North) is less or equal 10 then accepted

Hide this comment

Comment from Tilo on 31 March 2011 at 17:59

Great! thanks a lot.

Hide this comment

Comment from Tilo on 1 April 2011 at 04:36

I just tested a little smaller request than 10 square degrees with the request below (9.8 sqdeg) and ran into an Error. see the message below from http://jxapi.openstreetmap.org/xapi/admin/stats

ERROR way[boundary=administrative][bbox=8,48,10,52.9] 144 30 mins 32.909 secs

What is wrong with the request? Is there another reason for denial than the bounding box?

Thanks

Hide this comment

Comment from Tilo on 1 April 2011 at 05:12

this worked:
way[boundary=administrative][bbox=8,48,10,52] (221655 elements)

but this didn't:
way[bbox=8,48,10,52]

???

Hide this comment

Comment from malcolmh on 5 April 2011 at 09:44

Bounding boxes that straddle 180 E/W are rejected. I assume this is because West > East. Is this a bug or a feature?

Hide this comment

Comment from iandees on 5 April 2011 at 10:47

This is not a good place to make bug reports. Do that here: https://github.com/iandees/xapi-servlet/issues

Hide this comment

Comment from iandees on 12 April 2011 at 20:05

********THIS IS NOT A GOOD PLACE TO MAKE BUG REPORTS************. Do that here: https://github.com/iandees/xapi-servlet/issues

Hide this comment

Comment from Langlaeufer on 17 April 2011 at 12:36

sorry, I do not like to register there!

Hide this comment

Comment from Bryce C Nesbitt on 27 April 2011 at 06:59

Great! Thanks for making progress brining xapi back to life!
It would be nice if the status page at http://jxapi.openstreetmap.org/xapi/admin/stats gave details on the ERROR, rather than simply saying ERROR.

Hide this comment

Comment from Tilo on 28 April 2011 at 02:51

I agree with Bryce on both!

about 14 days ago this request: *[bbox=8.173,49.815,9.173,50.554] worked fine.
size 523 MB

Yesterday in the afternoon and today (at night) I always got an error. I tried 5 times each. Neither the bbox limitation of 10 sqare degrees (less than 2 sqdeg here) nor the syntax should be a problem in this request. What are the other limitations which cause an error?

Have new limitations been implemented between apr,14 and apr,28?

Hide this comment

Comment from iandees on 28 April 2011 at 02:52

********THIS IS NOT A GOOD PLACE TO MAKE BUG REPORTS************. Do that here: https://github.com/iandees/xapi-servlet/issues

Hide this comment

Leave a comment

Parsed with Markdown

  • Headings

    # Heading
    ## Subheading

  • Unordered list

    * First item
    * Second item

  • Ordered list

    1. First item
    2. Second item

  • Link

    [Text](URL)
  • Image

    ![Alt text](URL)

Login to leave a comment