Comparing Map Services Through Mashups

Flash EarthWe recently discovered a few map mashups, Flash Earth and Map Compare, which allow you to compare a variety of mapping APIs (Application Programming Interface). The first, Flash Earth, as its’ name implies uses Adobe Flash to pull in aerial and satellite imagery from Google Maps, Virtual Earth, Yahoo! Maps, Ask.com, OpenLayers, and NASA Terra. This zoomable mashup allows you to directly compare the different map services within their aerial or satellite mode. It was really interesting to see the different imagery that each service provided. Often times, if your zoomed in far enough you’ll find missing data from one service or imagery that varies by season, color, and quality. I’ve never experienced this type of comparision through any other mashup. Most of them tend to focus on street level mapping where the only thing that seems to change is the pixel width of the streets. An amazing feature found in Flash Earth is the ability to rotate the entire map in any direction using the navigational compass. You can also zoom using your keyboard or mouse wheel and it provides the ability to search a location with a street address or through latitude and longitude. Another little trick on Flash Earth is the ability to create a permanent link to your map location. This has typically been problematic when developing these types of applications in Flash.

To create this mashup the creator, Paul Neave, used “unofficial techniques” to pull in the imagery. In doing so he was able to gain better control over the service. The navigation is quite smooth because the zoomable interface was developed using Flash. Ajax mashups typically have to refresh when you zoom because image tiles need to be swapped out. When I asked Paul about how he worked around the API, he mentioned he pulled the “map images (tiles) directly by accessing their URL rather than using the JavaScript API.â€? He continued, “The API doesn’t allow you to do this, you must use their interface and layout to access the imagery. Once the files are downloaded, they’re stored in your browser’s cache similarly to the Ajax version.â€? In this instance the advantages over Ajax are apparent in the ability to more easily modify the imagery and enhance the interaction to make a more cohesive user experience.

Map Compare MashupOn the other side, Map Compare displays three maps together using Ajax. It combines Virtual Earth, Google Maps, and Yahoo! Maps. It allows you to compare all three simultaneously. One of the more interesting observations between the three was the lack of mouse wheel support for Google Maps. Virtual Earth was the only one that attempts to smooth the zoom level transition by adding an effect (similar to Flash Earth). It didn’t seem to work properly and added even more of a distraction than the image reloading delay. However, Virtual Earth did offer an interesting “Bird’s eyeâ€? view, a nearly isometric view into major cities. You can then rotate your camera perspective into the four cardinal directions within this view.

In addition to this mashup, I was able to find a more technical comparison by James Church who looks at the Yahoo! and Google Map APIs side-by-side. If your looking for even more examples, you can visit Google Maps Mania. For more unusual sightings you might want to take the guided tour at Google Sightseeing. With nearly half of all mashups using some variety of mapping software we were happy to find some ways to compare these services.

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