Sometimes GIS are complicated. Especially when it comes to access to data. I remember when I was building a dynamic routing engine based on PostGIS and data from Navteq. The dynamic part consisted of different vehicles behaving different in traffic. For example a truck or bus doesn't behave in the same way as a motorcycle or car. And moreover there can be obstacles, for example height and weight on bridges or the curve is too narrow. Most of the routing engines today are fast - not dynamic, or dynamic and less fast.
However, after discussed with a good friend about the secret keys to routing, using most of networks SQL indexes skills, adding some routing tricks we manage to make it pretty fast and dynamic, for the time being (2011). But it was hard to make it scale. Routing is CPU heavy and there are no rights and wrongs when it comes to routing. For example, the best route can be the shortest, fastest, safest or maybe most beautiful!
IsochronesDuring that time I also played with isochrones. An isochrone is the routing extent, for example 50 km from a given point. Not just a circle. In every case 50 km radius covering a bigger area than the corresponding isochrone. I have seen many municipalities using radius for example for the fire department. However, project Nanjing addresses that issue.
|Radius and Isochrone showing approximately 60 km from|
After trying the Nanjing API for the first time I was a bit surprised. I expected a GeoJSON as response, but it was a JSON with geographical information. It is not a big thing and it is easy to serialize - but I was surprised. My experience is to use standards whenever it possible. And in this case sending geographical information as JSON I use GeoJSON. The projects API is pretty straight forward to use and there are examples in a handful of languages.
However project Nanjing as a really new cool useful geospatial feature available for preview as today. I hope it will be part of the Bing Maps platform since it address an important useful feature.
There are several others project available for preview and a presentation on channel9.