Little-osm

Software described on this page or in this section is unlikely to be compatible with API v0.5 deployed on 8 October, 2007. If you have fixed the software, or concluded that this notice does not apply, remove it.

Software described on this page or in this section is unlikely to be compatible with API v0.6 deployed on April 20, 2009. If you have fixed the software, or concluded that this notice does not apply, remove it.

The current OSM server can hardly stand all the requests. Caches are needed. So little-osm is a start for any users that just want to read the data in their favourite application.

little-osm is an simple and primitive OSM server, aimed to be executed at anyone's home machine.

little-osm is intended as a read only server!

Contents 1 Warning 2 Installation 3 What are differences? 4 Package layout 5 Database layout

Warning

the README file contains partly incorrect instructions. The instructions below do work (at least on July, 11 2007)

Installation

• Get the Openstreetmap source code
• The little-osm codebase is under /applications/utils/little-osm/ in the main codebase
• Get ruby, rubygems and mysql ('gem install mysql', on Debian-based distros install the packages 'rubygems libmysql-ruby mysql-server', on Mandriva install the packages ruby, mysql and ruby-mysql)
• Get the planet.osm from somewhere. (http://josm.openstreetmap.de/wiki/Mirrors) and put this (unzipped) file in /applications/utils/little-osm/
• run 'mysql -u root < planet.sql' to create the table
• run 'ruby readxml.rb'. This will take awile. If you get errors after an hour, you have a corrupt planet.osm (Bugreport to user:Imi Imi)
• run the server with 'ruby server.rb'

What are differences?

There are some differences to the main server's map request:

• little-osm will order the objects in any arbitrary order.
• only nodes within the bbox are transfered. (The main OSM server also transfer nodes to line segments which have the other end in the bounding box.)
• segments, that cross the corners are transfered as well (but not their nodes). Some segments that actually do not cross the bbox could be also transfered.

Package layout

./readxml.rb	Script to convert a planet.osm into a mysql database
./planet.osm	here, you have to copy the planet.osm to read in.
test/*	Some unit tests.
api/	All API files reside here.

Database layout

The database in an very optimized format (for map-queries). It consist only of a single table:

CREATE TABLE `data` (
 `uid` int(10) unsigned NOT NULL default '0',
 `tags` text,
 `time` timestamp NOT NULL default CURRENT_TIMESTAMP on update CURRENT_TIMESTAMP,
 `reference` text,
 `min` point NOT NULL,
 `max` point NOT NULL,
 KEY `Index_1` (`uid`),
 spatial (`min`),
 spatial (`max`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;

(see file applications/utils/little-osm/planet.sql)

• The uid is unique among all entries. It is the osm-id shifted by 3 bits, added 1 for segments and 2 for ways.
• The tags are an \n - seperated list of keys and values (key1\nvalue1\nkey2\n...).
• reference is empty for nodes, "from_id,to_id" for segments and "seg1,seg2,seg3..." for ways.
• The other coordinates are the bounding boxes for the object. For nodes, the bounding box is always only a point.