Changeset 241
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- 09/24/08 11:47:30 (2 months ago)
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branches/workshop/FOSS4G2008/Docs/04_openstreetmap.chapter
r240 r241 1 OpenStreetMap uses a topological data structure. 1 = About OpenStreetMap = 2 3 "OpenStreetMap is a project aimed squarely at creating and providing free 4 geographic data such as street maps to anyone who wants them." 5 "The project was started because most maps you think of as free actually have 6 legal or technical restrictions on their use, holding back people from using 7 them in creative, productive or unexpected ways." 8 [Source: http://wiki.openstreetmap.org/index.php/Press] 9 10 OpenStreetMap uses a topological data structure: 2 11 3 12 * Nodes are points with a geographic position. … … 6 15 * Tags can be applied to nodes, ways or relations and consist of name=value pairs. 7 16 8 That's how nodes ways and relations are specified in a real OSM file: 9 17 This is how nodes, ways and relations are described in the OpenStreetmap XML 18 file: 19 20 {{{ 10 21 <?xml version='1.0' encoding='UTF-8'?> 11 22 <osm version='0.5' generator='JOSM'> … … 56 67 ... 57 68 </osm> 69 }}} 58 70 59 The OSM file can be downloaded from OpenStreetMap website using an API (see http://wiki.openstreetmap.org/index.php/OSM_Protocol_Version_0.5), 60 or with any software which supports OSM format, for example JOSM. 71 The OSM data can be downloaded from OpenStreetMap website using an API 72 (see http://wiki.openstreetmap.org/index.php/OSM_Protocol_Version_0.5), 73 or with some other OSM tools, for example JOSM editor. 61 74 62 We take only nodes and ways of types and classes specified in mapconfig.xml file to be converted to pgRouting table format: 75 Note: The API has a download size limitation, which can make it a bit 76 inconvenient to download extensive areas with many features. 63 77 78 When using the osm2pgrouting converter (see later), we take only nodes and ways 79 of types and classes specified in "mapconfig.xml" file to be converted to 80 pgRouting table format: 81 82 {{{ 64 83 <?xml version="1.0" encoding="UTF-8"?> 65 84 <configuration> … … 75 94 </type> 76 95 </configuration> 96 }}} 77 97 78 Detailed description of all possible types and classes can be found here - http://wiki.openstreetmap.org/index.php/Map_features. 98 Detailed description of all possible types and classes can be found here: 99 http://wiki.openstreetmap.org/index.php/Map_features. 79 100 101 For Cape Town the OpenStreetMap data is very comprehensive with many details. 102 A compilation of the greater Cape Town area created with JOSM is available as 103 capetown_20080829.osm.
