Book Image

Building Web and Mobile ArcGIS Server Applications with JavaScript ??? Second Edition - Second Edition

By : Eric Pimpler, Mark Lewin
Book Image

Building Web and Mobile ArcGIS Server Applications with JavaScript ??? Second Edition - Second Edition

By: Eric Pimpler, Mark Lewin

Overview of this book

The ArcGIS API for JavaScript enables you to quickly build web and mobile mapping applications that include sophisticated GIS capabilities, yet are easy and intuitive for the user. Aimed at both new and experienced web developers, this practical guide gives you everything you need to get started with the API. After a brief introduction to HTML/CSS/JavaScript, you'll embed maps in a web page, add the tiled, dynamic, and streaming data layers that your users will interact with, and mark up the map with graphics. You will learn how to quickly incorporate a broad range of useful user interface elements and GIS functionality to your application with minimal effort using prebuilt widgets. As the book progresses, you will discover and use the task framework to query layers with spatial and attribute criteria, search for and identify features on the map, geocode addresses, perform network analysis and routing, and add custom geoprocessing operations. Along the way, we cover exciting new features such as the client-side geometry engine, learn how to integrate content from ArcGIS.com, and use your new skills to build mobile web mapping applications. We conclude with a look at version 4 of the ArcGIS API for JavaScript (which is being developed in parallel with version 3.x) and what it means for you as a developer.
Table of Contents (21 chapters)
Title Page
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Customer Feedback
Preface

Map events


In programming, events are actions that take place within an application. Normally these events are triggered by the end user and can include things like mouse clicks, mouse drags, keyboard actions, and others, but can also include the sending and receiving of data, changes in state of a user interface component, and many other scenarios.

The ArcGIS API for JavaScript is an asynchronous API that follows a publish/subscribe pattern wherein an application registers (publishes) events with listeners (subscribers). The following diagram illustrates this process. Listeners are responsible for monitoring the application for these events and then triggering a handler function that responds to the event. Multiple events can be registered to the same listener. The dojo on() function creates a listener that associates an event to a handler function:

As you'll recall the ArcGIS Server JavaScript API is built on top of Dojo. With Dojo, events are registered to handlers through the dojo on(...