) and update with the census data (using the

The US Census Bureau provides an API for querying data in a number of ways. This post will not describe the Census API, other than to say that the data is returned in JSON format. We use the state ID, provided in the 2nd column, to look up the existing state data (using the

Data can be styled through the use of a

Data.StyleOptions

object or through a function that returns a

Data.StyleOptions

object. Here we create a choropleth map by applying a gradient to each polygon in the dataset based on the value in the census data.







In addition to the coloring, we've created an interactive element by adding events that respond to mouse activity. When you hover your mouse cursor (or finger) over a region with data, the border becomes heavier and the data card is updated with the selected value.







We’ve also used a

custom basemap style

in this example to provide some contrast to the colorful data.







Check out

Google Maps Engine

if you need somewhere to store your geospatial data in the cloud, as we’ve done here. If you have any questions on using these features, check out the docs for the

data layer

and the

Maps Engine API

or head over to

Stack Overflow

and ask there. You can also check out this article’s

permanent home

, where the interactive version lives.