Now that the introductions are out of the way, we should begin working with the API. In this chapter, we're going to look at some code that will make a simple, interactive map. The example will be a single-page application, with all the styling and coding on the same page. In the real world, we would want to separate those into separate files. For this example, this is what the project is comprised of:
Setting up an HTML5 web page
Adding the necessary styling and the ArcGIS JavaScript library
Framing out our HTML content
Setting up a script to create a map
Loading a layer file
Adding a click event that collects data from the map service
Displaying that data on the map
We've just been asked by the Y2K historical society to make an interactive map application of the United States around the year 2000. They want the application to show the U.S. demographics including gender, age, and ethnicity, during that year. After reviewing the request from the client, we determined that the 2000 census data would provide all the mapping and demographics data we were looking for.
After a bit of research, we found an ArcGIS Server map service that serves the 2000 census data. We can use the ArcGIS JavaScript API to show that data on an HTML document. The user will be able to click on the map, and the application will display census data by state, census tract, and census block group.