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

Chapter 7. Identifying and Finding Features

Being able to identify features and find out information about them is a common requirement in web mapping applications. In this chapter we're going to cover two ArcGIS Server tasks related to returning feature attributes: IdentifyTask and FindTask.

IdentifyTask returns the attributes of features that have been clicked on a map. The attribute information is often presented in a pop-up window. As with the other tasks we have seen, the IdentifyTask object relies upon input parameters, in this case an object called IdentifyParameters that controls the results of the identify operation. These parameters include which layers in a service to use for the identify operation, and an acceptable distance from a feature for it to be considered as relevant to the map click location. An instance of IdentifyResult is used to hold the results of the task. More often than not, the tasks that you can execute with the ArcGIS API for JavaScript replicate some of the...