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

Feature selection


FeatureLayer also supports feature selection. Selected features are a subset of the features in a layer which can be used for viewing, editing, analysis, or as an input to other operations. Features are added to or removed from a selection set using either spatial or attribute criteria. The features in the selection set are often drawn with different symbologies to differentiate them from the other features in the layer.

To create a selection set, use the selectFeatures(query) method on FeatureLayer. A parameter is a Query object exactly like the one you have already seen with QueryTask. This is illustrated by the following code example:

var selectQuery = new Query(); 
selectQuery.geometry = geometry;
 featureLayer.selectFeatures(selectQuery,FeatureLayer.SELECTION_NEW);

We haven't covered the Query object in detail yet, but just like in QueryTask, you use it to define the input parameters for an attribute or spatial query.

The preceding screenshot shows a feature that has been...