Case Studies

Since joining the FOSS4G conference 2007 in Vicrtoria, Canada I felt, that OpenLayers is the coming "star" on the “OpenSource webbased GIS software-sky“. Since them we started running numerous projects with OpenLayers as the core-mapping component in our company. But with the upcoming complexity of the projects, there was a strong need for a more powerful client. So we started a piece of software, that we called our "core", which was a kind of marriage between OpenLayers, XML-configuration and the JQuery library.

Now, four years later there are numerous OpenSource projects with OpenLayers as the mapping component together with a powerful Javascript-library.

The talk will introduce and compare the mapping toolkits GeoEXt, MapQuery and Legato, which all use OpenLayers as their mapping-component, Although the named toolkits are different in their architecture, they have the same focus we had: The need for a more powerful webmapping client with smooth functionality. GeoExt uses ExtJs as library, MapQuery is based on the Javascript library JQuery and Legato is mor focussed on configuring OpenLayers via XML, but also delivers extensions such as a layertree for example. Beside the technical view I will also try to illuminate the state of the projects in the community and the interactions between the mapping-toolkit library and the OpenLayers project.

Of course a comparison must be kind of "subjective" but the talk tries to be as uncommitted as possilbe. Regarding the jungle of Fossgis projects it is always difficult to find out, which piece of software maybe the best for a particular project. This talk will try to give some benchmark data to hit the spot.

Grassroots Mapping (grassrootsmapping.org), an online network of participatory, community-based mapping projects, was established in early 2010, just prior to the BP Gulf of Mexico disaster. In response to the spill, the grassroots mapping community worked with the Louisiana Bucket Brigade, a New Orleans based non-profit, to carry out volunteer mapping trips to affected areas of the Gulf Coast. Using low cost kites and balloons with consumer point and shoot cameras attached, volunteers with minimal training collected imagery by land and sea beginning in April 2010. Tens of thousands of images were collected over this period of time on over 50 mapping missions. The images were processed, orthorectified, and stitched into maps using GDAL and other FOSS4G tools. A new FOSS4G tool for processing raw aerial imagery into maps, Cartagen Knitter, was developed for this project by Jeffrey Warren of the MIT Center for Future Civic Media. This collaborative effort has resulted in dozens of high resolution maps made available to the public for use without restriction. Typical map resolutions range from 3-7 cm per pixel compared to 100 cm per pixel for Google Maps or similar online map products. Additional benefits include data ownership, temporal relativity, and a greater understanding of related issues by volunteers due to the participatory nature of the effort.n