This tutorial describes the steps to carry out to be able to serve specific items filtered from Open Street Map as web service.
- open street map tile
- osm2pgsql (stand alone tool osm2pgsql)
Create a new database and give it a representative name (e.g. osm). Select the new database in the tree and open the query tool (Ctrl+e, or select the query tool from the <tools> menu). Paste in the following four lines of code.
CREATE EXTENSION postgis;
CREATE EXTENSION postgis_topology;
This will set up the necessary schemes in the database.
Store data in the database
Next, the osm2pgsql tool will be used to get the data from the OSM file into the database. This file can be downloaded from http://customdebug.com/osm/osm2pgsql.zip. Extract this file somewhere on your hard drive.
Also download the style file from https://raw.github.com/openstreetmap/osm2pgsql/master/default.style and place it in the same location as osm2pgsql. This file is necessary to prevent the osm2pgsql tool from looking for the file in a UNIX based location.
Finally, download the OSM data. As an example we will use Mexico as our subset of data. The file we used was downloaded from http://download.geofabrik.de/central-america/mexico-latest.osm.bz2. Extract the contents to a location on the hard drive.
There is an alternative way. OSM can be filtered before downloading, please check http://wiki.openstreetmap.org/wiki/Overpass_API. For Coastlines the following query can be used in the so called Overpass Turbo OSM Api.
This has been generated by the overpass-turbo wizard.
The original search was:
// gather results
// query part for: “Coastline”
// print results
out skel qt;
The following two commands will perform the database operations necessary for creating the tables in the database that was just created.
osm2pgsql.exe -c -k -S default.style -U username -H localhost -P 5432 -d osm location\to\mexico-latest.osm
Replace password, username and location\to\mexico-latest.osm with the correct values. localhost is the server of the database, 5432 the port which the database listens to (default values). Also, it is assumed that default.style is in the same directory as osm2pgsql.exe.
First, download the following two style files. These will be used to give the data its looks.
Navigate to the GeoServer administration console and log in. From the left menu, select Services>WMS. Scroll down to the Max rendering memory (KB) options and set this value to 262144.
Next, go to Data>Styles from the left menu and select Add a new style.
Fill in the properties and use the contents of the style_osm_line.sld file.
Next, go to Data>Styles from the left menu and select Add a new style, but now fill in the properties and use the contents of the style_osm_polygon.sld file.
Importing PostGIS database as layers in GeoServer
Select Data>Stores from the menu. Select add a new store from the top.
Fill in the following properties and save:
Next, select Data>Layers from the menu on the left. Select add a new resource.
Select the Local GeoServer instance from the dropdown list and select publish from the action column for the planet_osm_line layer.
In the first tab (Data), make sure Native SRS and Declared SRS are both set to EPSG:900913, then select compute from data and compute from native bounds.
In the second tab (Publishing), select the osm-line style. Then scroll down and press the save button.
Perform the same actions to add the polygon layer.
Testing the geoserver
Everything should be setup now and the server can be used to retrieve geospatial data from the database. To test whether the layers are correct, it is possible to create a layer preview. This can be performed by selecting Data>Layer Preview. From the Common Formats column select OpenLayers. Other formats can also be tested by selecting a format from the dropdown menu from the All formats column.