ChizuBroker |
Introduction
ChizuBroker provides applications with consistent dynamic access to maps from various online sources. Chizu is the Japanese word for map, and we might have called this application MapBroker if someone else hadn't already claimed the name.
ChizuBroker provides maps as rasterized images, rather than in any vector form. While vector maps scale more nicely, they are not as readily available on the Internet. Usually ChizuBroker retrieves the maps by sending CGI requests to the sources. Once we move beyond a prototype stage we need to clear up the licensing issues associated with doing this.
Applications ask ChizuBroker for a map by specifying the center of the map (latitude and longitude), the scale, and the screen area (pixels high and wide) which needs to be filled. When applications connect to ChizuBroker, they indicate which language the user prefers for the labels on the maps, and if possible ChizuBroker takes this into account. Applications can specify that a particular map source be used, or let ChizuBroker choose.
Some map sources only provide maps at predetermined scales. In this case ChizuBroker uses Java Advanced Imaging (JAI) to stretch a larger scale map to the desired screen size. This can make the maps look somewhat less pretty, but usually they are still readable. Note that the client application doesn't need to install JAI; this stretching takes place on the server.
Simple demonstration applet (requires Java Plug In - firewall friendly version).
Documentation of ChizuBroker API (javadoc)
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