Creating Maps and Adding Layers

We all have to start somewhere when learning a new programming language or Application Programming Interface (API). The same applies to creating web mapping applications with the ArcGIS API for JavaScript. Not only do you need to understand some basic JavaScript concepts but you also need to have a grasp of HTML, CSS, and of course the ArcGIS API for JavaScript, which is actually built on top of the Dojo JavaScript framework. That's a lot to put on your plate at once, so in this chapter we'll have you create a very basic application that will serve as a foundation which you can build on in the coming chapters.

Mimicry is an excellent way to learn programming skills, so in this chapter I'm just going to have you type in the code that you see and we'll provide some explanation along the way. We'll save the detailed descriptions of the code for later chapters.

To get your feet wet with the ArcGIS API for JavaScript you're going to create a simple mapping application in this chapter that creates a map, adds a couple of data layers, and provides some basic map navigation capabilities.

Let's get started!

In this chapter we'll cover the following topics:

• The ArcGIS API for JavaScript Sandbox
• Basic steps for creating an application with the ArcGIS API for JavaScript
• More about the map
• Working with map service layers
• Tiled map service layers
• Dynamic map service layers
• Map navigation
• Working with the map extent