Map mashups continue to be extremely popular, as evidenced by the high percentage of mapping APIs in our web service directory and map mashups in our mashup directory. Whether you're just getting started with map mashups, or you're a veteran map mashup developer, there are several tools out there that can help with your development efforts.
Here are three ways to make your map mashup stand out above the crowd.
Image overlays allow you to enhance your mashup by including information that is not typically found in the standard maps of the major mapping APIs. If you're looking to integrate images that are not spatially referenced (e.g., scanned maps or drawings) with your map mashups, there are several tools out there that will convert and transform your images into a format that can be used with a mapping API.
Microsft's MapCruncher allows users to easily create spatially-referenced image tiles that can be integrated with some of the mapping APIs. Although MapCruncher is aimed at integration with Virtual Earth, there are ways to integrate the image tiles generated by MapCruncher with Google Maps, including this nice tutorial by Bill Chadwick. Note that unfortunately MapCruncher only works on Windows.
Yahoo! offers a similar web-based tool called MapMixer, but uploaded images can only be displayed within Yahoo! Maps. However, the ability to do all of the image manipulation online may be attractive for users that want to avoid downloading a desktop application and/or users that are not running Windows.
Integrating large geospatial data sets with map mashups can be challenging, especially if you are also trying to classify that data based on different attributes. If you are looking to add thematically classified data to your maps, one option is to pre-generate image tiles that can subsequently be added the same way as image overlays.
The UCL Centre for Advanced Spatial Analysis offers its GMaps Creator desktop tool as a free resource for creating thematic map overlays for Google Maps. With this tool users can take existing GIS data in shapefile format and create sets of image tiles that can be integrated with Google Maps via the API. If you've ever wanted to display large geospatial data sets with Google Maps, this tool can be quite useful. Note that only polygon data are currently supported.
Small changes can go a long way with your map mashup. Using custom icons provides subtle visual cues for your users in addition to making your map mashup unique. The Mapki web site lists several resources for creating your own map icons. Strategies range from using photoshop to create a graphic and corresponding shadow to dynamic generation of icons via online tools.
If you're looking to quickly create a set of map icons online, you should check out the Map Icon Maker, which is hosted by Google and uses the Google Charts API to dynamically generate an icon use in Google Maps mashups. Another alternative is the mapicon Factory, a "freemium" service provided by CartoSoft that allows users to generate map icons in PNG format (disclaimer: I am the founder of CartoSoft).
We have additional map mashup resources listed in our How To section. Check out some of the more popular map mashups for inspiration for your next map mashup, and keep us posted on any new map mashups you develop.