The map (and other path/object) data in the catalog is being supplied mostly in file formats that require specialized tools. Although there are open source tools available for some of the formats, those tools remain relatively specialized and require some specific domain knowledge to be able to use at all.

SVG is a graphic/object format that is supported directly by most current web browsers (including mobile devices). As an XML-compatible format, there are a lot of existing code libraries that can be used to work with it. It can also be used directly by JavaScript in browsers (and can be combined with the lastest CSS effects for some powerful visualizations), reducing the need for data format readers/translators when building dynamic web applications.