proj4js can't find proj4js.js because it's called proj4js-compressed.js

in proj4js there is a getScriptLocation function which retrieves the path of the current script by looping over the script tags in the document. Unfortunately the function won't find the scriptlocation if your script is called proj4js-compressed.js in stead of proj4js.js.

This results in proj4js won't find extra projections, which results in errors in your page when trying to call a non standard projection.

So change the name of the script to proj4js.js (or include the needed projections by hand)

And if you need EPSG:102113 (the Esri alternative for the common mercator projection), copy EPSG900913.js to EPSG:102113.js and change ['EPSG:900913'] to ['EPSG:102113'].

one week open source primer

A company asked us to provide a one week open source primer for their employee's. This is the program we proposed:

mo:
Quantum GIS
Mapserver, Gdal

tu:
Udig
GeoServer

we:
PostGIS
GeoKettle

th:
OpenLayers, GeoExt
MapBender

fr:
GeoNetwork
Oracle, Autocad and Esri support in Open Source Apps

Bolsena Hacking Event 2010

These days i'm in Italy to visit the Bolsena Hacking Event 2010. A group of open source GIS developers meets every year to work on several projects. I'm here to work with GeoCat developers on a ArcGIS-GeoNetwork bridge extension. But in the meanwhile I have interesting discussions with and presentations of developers of GeoServer, MapBender, Deegree, GeoCouchDB, GeojQuery, OpenLayers, Inspire and Grass. Send me a message if you'd like to bring in a subject.

Rotation in SLD and Esri

In ArcMap you can rotate point symbols geopgraphic and arithmatic. SLD/Geoserver rotates features in only one direction (geographic). So to get the arithmatic rotation in GeoServer (based on a field value) you should multiply the Esri-direction by -1:

<sld:Rotation>
<ogc:Mul>
<ogc:PropertyName>RICHTING</ogc:PropertyName>
<ogc:Literal>-1</ogc:Literal>
</ogc:Mul>
</sld:Rotation>

* <ogc:Mul> is the multiply implementation of SLD (all functions)

To get geographic rotation you have to add 90 degrees.

SLD for GeoServer from QGIS

To be able to publish proprietary formats on the internet using open source techniques, one of the mayor chalanges left is the definition of styling (or export/import of styling from the proprietary system). QGIS not only offers a set of data conversion tools and styling interface, it also contains a mapserver export plugin, with which one can export the styling of a set of layers to mapserver to be published on the internet.

Last year Luca Casagrande launched a SLD export plugin (python). These SLD's can be used to define styling for data published with GeoServer. It's an early version (only supports vector layers with unique values-styling), but it's a great starting point for starting out with SLD and GeoServer. Create styles in QGIS, download the plugin, put it in /qgis/python/plugins and activate it in 'manage plugins' section of QGIS. An 'SLD' button is added to your toolbar, which opens a dialog with the SLD for the styled layers.

For GeoServer there is a great webbased styling tool out there. It's an early version (only firefox 3). The tool is build using GeoExt and uses the GeoServer REST-API (installed as a geoserver plugin) to save the created styles in GeoServer. the tool can not be downloaded with the latest stable geoserver 2.0.2, but it's available with the 2.0.0 version. The styler is also present in the OpenGeo Geo Suite (a suite of opensource GIS applications).