Dr. Dobb's Journal - December 2007 - (Page 36)

d12synd_p4ma 10/12/07 8:38 AM Page 36 State of the Art by by Dionysios G. Synodinos Web Maps with the Google Map API Dionysios is a web engineer at the National Technical University of Athens and a freelance consultant. He can be contacted through his blog at http://synodinos.wordpress.com. Google has provided web developers with a feature-rich toolset for representing geographical information A common challenge for many web developers is the creation of web applications that capture and describe geographical information. Nowadays, online maps are showing up everywhere, either as standalone applications or as modules for larger portals and services. For such tasks, traditional image-based solutions fall short because the acquisition of the media tends to be expensive as they involve air photographs or copyrighted geopolitical maps. In the case of large-scale maps, the ad hoc use of satellite imaging can prove even more costly. Also, for this imaging to be easily available with the proper degree of usability, it requires lots of coding, which often introduces incompatibilities for many browsers. Some vendors attack the problem by using proprietary plug-ins and development environments. But this approach still has many of the same problems as the final product is bound to specific environments and requires major funding for licensing. For the last five years, we had been using a proprietary solution to manage a small percentage of the geographical information about various university locations. This solution had only a few locations and would run in only one browser on one operating system. Moreover, it required users to download a big plug-in. Also, it wasn’t stable under heavy use. For the next version of our service, we wanted to map more locations—in fact, everywhere in the country where the university has locations for labs, research facilities, and the like. The front-end would have to be stable and operate on all major operating systems and browsers. It would also have to be flexible enough for us to build features and functionality. Finally, it should be a solution that has the acceptance of the rest of the market since we wanted to make a long-term investment that would pay off as our service would scale. In this article, I present our solution—a web frontend that utilizes several aspects of the freely available Google Map API to provide a usable, robust, crossplatform web map. Getting the Right Coordinates To get the precise geographical location for specific sites, you could use some kind of a geocoder tool. 36 Dr. Dobb’s Journal l www.ddj.com l December 2007 http://synodinos.wordpress.com http://www.ddj.com

Table of Contents Feed for the Digital Edition of Dr. Dobb's Journal - December 2007

Dr. Dobb's Journal - December 2007 Contents Hmmmm Alia Vox Developer Diaries Developer’s Notebook Computer Books: Reading Between the Lines Conversations Query Anything with SQLite XQuery Web Maps with the Google Map API OpenALM and Its Manifesto Transactional Programming Effective Concurrency The Agile Edge Swaine’s Flames

Dr. Dobb's Journal - December 2007

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