Today I finished the first draft of a terrain google map with a D3 overlay to show recent sightings of Black-chinned and Ruby-throated hummingbirds from the eBird API (Cornell University).
I like this version compared to the previous D3 only version as the terrain map shows us some interesting information to consider. In the previous D3-only version, radius of circle increased with number of sightings. Here, the color of the circle is darker with increasing number of sightings. Also, in this version, I filtered the eBird json array for objects that are missing the number of sightings, which was messing with the color scheme I had developed.