The recent popularization of certain web technologies used by Google Maps has encouraged the development of more interactive web mapping techniques. Google's web mapping tools use a technology known as AJAX (Asynchronous JavaScript and XML). AJAX is a style of web application development that uses a mix of modern web technologies to provide a more interactive user experience. Wikipedia has a good discussion of AJAX technology.

By using AJAX, Google's maps draw and zoom quickly, pan smoothly, and can be extended to display a wide variety of information. This article shows how to make similar AJAX-based web mapping sites using an open source web mapping toolkit called ka-Map. ka-Map uses the MapServer web mapping server behind the scenes with AJAX and PHP to serve up the map content. All this comes together to provide a highly interactive means to viewing maps online.

Google Maps provides some very powerful tools, but once you want to add your own data layers, or further customize your own components, it may be easier to use your own toolkits. Tools exist for creating your own AJAX-based web mapping sites and are fairly easy to use. ka-Map coupled with MapServer is a powerful combination of open source web-mapping technologies. For a good example of a ka-Map application see DM Solutions Group's Maps for MapServer site.