Tuesday, March 30, 2010

Tuesday Tools: Map Symbol Brewer

What is Map Symbol Brewer?

The development of the Map Symbol Brewer tool was part of Olaf Schabel's PhD Thesis at the Institue of Cartography in Zurich, Switzerland. The goal of the project was to create a tool that would allow for the easy visualization of statistical data with map symbols. Other tools, such as the data-graphic environment SageTools, had already existed that could automatically generate map symbols. However, Map Symbol Brewer aims to generate customized map symbols using a step by step process that is based on the data that is input and the needs of the user. The final product is an online application that generates complex user-defined map symbols that can be used in interactive map applications.


The Map Symbol Brewer tool uses the idea of primitives in map symbols. Primitives are basic shapes for map symbols and include ellipses, symmetric polygons, and pie sectors. From these basic shapes, the following simple map symbols can be generated.

Data values are used to construct and scale these primitives.  For example, bigger data values generate bigger symbols.  In addition to primitives there are diagrams, which are used for symbols that need to represent multiple data values. Diagrams can follow eight different arrangement principles as shown in the following table developed by Schabel :

Using the Map Symbol Brewer Application

To use the Map Symbol Brewer application, visit the website. You can either upload your own data or use the European map and test data provided. If you are having trouble uploading files, read how to structure your upload files.  Once the data is uploaded, you can generate the map symbol description by developing the DiaML (Diagram Markup Language) file.

DiaML Generation and Map Export

DiaML generation is a step by step process that is separated by tabs to the right of the preview map. First, you choose the type of the symbol you'd like to use. The options are a simple symbol for one data value or a diagram for multiple data values.  On the following tabs, you choose a primitive and set the primitive attributes, define their arrangement, and select the color scheme. In the fifth tab, you select guides for the map symbols or add an interactive component to the symbols. Finally, in the sixth step, you can export the map as a DiaML file in .xml format or as an SVG file.

In Schnabel's report on the Map Symbol Brewer, you can also find some example outputs of his prototype, such as the following: