So it has been a while since we posted, but the rationale was we’d wait till we had a working example of moving past push pins. This week we got our GeoIQ API working with the Google Maps API and have the first set of screen shots to show. One of the things we thought is really missing from web mapping applications, right now, is the ability to do geographic analysis. Even the ability to make basic decisions like – is location “A” better than location “B” is missing. With this first simple idea in mind we’ve built a quick mashup with Google Maps. We took our heat mapping API and integrated it with a split screen Google Maps viewer. That way you can look at two locations at the same time and compare them.
We wanted a fun data set to play around with and thought traffic congestion/delay would be interesting. The Bureau of Transportation Statistics (BTS) has a cool data set with average traffic delay for all the US highways available, so we threw that in. One of the problems with pushpins or polylines in Google Maps (and others) is there is no way to visualize what are the high value or low value pushpins. In this case, which road has high traffic delay and which roads have low traffic delay. We do this with a heat map (similar to Zillow, Google Adsense, etc.) that can be dynamically refactored as you zoom in/out (see previous post). We added to this heat map tool a concentration index – which gives you a score of the value (weight) of your pushpins and how closely they are located together. Once you have the score you can see if location “A” is better than location “B”. In this case is traffic delay more concentrated in location “A” or location “B”
The GeoIQ API creates a heat map based on an index that measures the amount of traffic delay on the roads and how closely that road delay is located to other delayed roads. The higher the delay and the closer together the roads, the hotter the map and the higher the score. The score ranges between 0 and 1. If all the traffic delay and highways were concentrated at one single location the score would 1 and if there was no traffic delay the score would be 0. In the map above traffic delay for Los Angeles in .26 and for San Francisco it is .15, so if you believe the BTS data traffic, LA is about twice as bad as SF. Lets go east coast – NYC vs. DC.
A comparison of the concentration of traffic delay in New York and Washington DC
According to this score NYC is a little worse than DC. The cool thing about the technology is you can run these comparisons on the fly as you zoom in and out of the map. So – let’s compare two big traffic bottlenecks in DC to see which is worse the I-270 Spur or I-95 Mixing Bowl.
A comparison of the concentration of traffic delay at the I-270 Spur and the I-95 mixing bowl – both in Washington DC
The Spur looks to get the better of the Mixing Bowl. In the app you can do this with any data set or mash up multiple data sets to solve a variety of problems surround location decisions. We’ll have more to come so stay tuned if this looks interesting.
Welcome to the Esri DC Development Center blog. We write about features of our work on big data analytics, open platforms, and open data, what is new and exciting in the Esri and community, and general industry thought leadership and discussions of geospatial data visualization and analysis.
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