ArcGIS Web Development

Rene Rubalcava

• Publisher: Manning
• Year: 2014
• ISBN:
  9781638355748
• Topic: Computer Science
• Subtopic: Programming in JavaScript
• Index: Computer Science

Summary ArcGIS Web Development is an example-rich tutorial designed to teach developers to use the ArcGIS JavaScript API to build custom GIS web applications. About the Technology Now you can unshackle your GIS application from a workstation! Using the ArcGIS JavaScript API, developers can build mobile and web-based maps and applications driven by ArcGIS data and functionality. Experienced ArcGIS developers will find that the familiar development environment provides a smooth transition to the web. Web developers new to GIS will be pleased by how easily they can apply their existing skills to GIS applications.Purchase of the print book includes a free eBook in PDF, Kindle, and ePub formats from Manning Publications. About the Book ArcGIS Web Development is an example-rich guide that teaches you to use the ArcGIS JavaScript API to build custom GIS web applications. The book begins with easy-to-follow examples that introduce readers to the ArcGIS JavaScript API and show how you can apply simple customizations. As the book progresses, you'll explore a full-scale, web-mapping application. By the end you will be able to build web apps that have features you'd ordinarily expect to find only in dedicated GIS applications.Written for web developers familiar with JavaScript and basic GIS concepts. Experience with ArcGIS is helpful, but not necessary. What's Inside

• Build web-based GIS applications
• Customize the ArcGIS Javascript API tools
• Bring ArcGIS data to the web
• Create secure logins for mobile app users

About the Author Rene Rubalcava is the cofounder of SmartGeoTech, Inc., a GIS development company specializing in Esri technologies. Table of Contents
PART 1 ARCGIS JAVASCRIPT FOUNDATION

• GIS as a tool
• Introducing core API concepts
• Working with the REST API
• PART 2 SAMPLE USE CASE
• Building an application
• Developing a custom data-collection application
• Building a desktop browser application
• Advanced techniques
• APPENDICES
• Setting up your environment
• Dojo basics
• Configuring a proxy

Part 1. ArcGIS JavaScript Foundation

Part one of this book introduces some of the core concepts of GIS and terms used throughout the book. By the end of this part, you’ll have a solid understanding of the ArcGIS Server REST API, which is the driving force for ArcGIS web technologies and core concepts of the ArcGIS API for JavaScript, as well as how spatial data is provided to web applications:

• In chapter 1, you’ll learn how to use GIS as a tool and the significance of spatial applications.
• In chapter 2, you’ll build your first map and learn the basics of spatial data and how to query that data. You’ll also learn the details of how a FeatureLayer works and how it’s optimized for performance.
• In chapter 3, you’ll learn the basics of the ArcGIS Server REST API and be given a sample of how to use it to build a custom legend widget. This is also the first dive into using the Dojo AMD loading system and modularizing your application.

Chapter 1. GIS as a tool

This chapter covers

• What a geographic information system (GIS) is and how it’s used
• The significance of spatial applications
• Trends for pros and opportunities for beginners
• Parts of a GIS web application

Where we are, and our understanding of location, has an impact on our daily lives. Walk around almost any public space and you’ll see people staring at their smartphones, updating their statuses, or looking for the closest taco joint. You may have shopped for a house online, and been able to view homes in your area and even see nearby schools. When shopping for a car online, you can usually limit the search to within so many miles of a zip code. Formerly, a paper map book was essential in every vehicle, but today, drivers keep a GPS (Global Positioning System) on the dashboard or have a system that speaks to them, directing them when to turn. If you’re following directions on paper, chances are you printed them from an online map. Location has become a key component of the way we get many tasks done. A simple map can be a driving force in delivering information, sometimes in the most subtle ways. ArcGIS, a key subject of this book, is a geographic information system (GIS) platform that allows users to work with maps and geographic information. With it, users can create and use maps, gather and analyze geographic data, and use that data in a variety of applications.

This chapter gives you a quick overview of the key pieces of information in this book:

• The ArcGIS platform
• Why you should consider learning how to add spatial capabilities to your applications
• Benefits of the ArcGIS API for JavaScript
• Dojo Toolkit and how it relates to the ArcGIS API for JavaScript
• Useful GIS concepts

Volumes have been written on the subject of GIS alone, but for our purposes, I’ll discuss what GIS means and how location-aware applications impact our daily lives.

1.1. GIS: here, there, everywhere

For years, GIS was something used by academics and government agencies for studies or infrastructure purposes. GIS is “a system designed to capture, store, manipulate, analyze, manage, and present all types of geographical data.”^[1] GIS is the way we work with spatial information. It’s also a technology that’s been used mainly in the realm of desktop computers, with large enterprise applications that require extensive training.

¹ “Geographic Information System,” Wikipedia, last modified May 24, 2014, http://en.wikipedia.org/wiki/Geographic_information_system.

The World Wide Web has caused an explosion in most technologies today, including the use of GIS tools. Since the mid-1990s, you’ve been able to find addresses and get directions from websites like MapQuest. Projects like Google Maps and OpenStreetMap emerged a few years later to bring GIS to the masses, introducing the power of maps to everyday people. Esri, founded in 1969, has grown into a leading company that provides GIS tools and services, including a suite of web mapping tools, which is why you’re reading this book. Before we take a closer look at Esri’s GIS offerings, let’s sample the other tools available.

1.1.1. The GIS tools landscape

You have a number of choices when it comes to developing web mapping applications with JavaScript, including robust open-source options. Some options come in the form of an API, which is an interface for an underlying web service, like maps and directions.

What exactly is a web service?

The World Wide Web Consortium (W3C) defines a web service as “a standard means of interoperating between different software applications, running on a variety of platforms and/or frameworks.”^[a]

^a “Web services Architecture,” W3C Web Services Architecture Working Group, last modified Feb 2004, www.w3.org/TR/ws-arch/

Google and MapQuest provide web mapping APIs that are popular for embedding maps and directions into websites. Microsoft offers a Bing mapping API to showcase its mapping data. Various open-source mapping libraries also have much to offer:

• OpenLayers— A popular open-source mapping library with a large community of users
• Leaflet— A mapping library that has grown in popularity due to its ease of use and focus on performance for mobile browsers
• Modest Maps— A super-lightweight mapping library that does a good job of displaying interactive maps

This list is a sampling of open-source options for building web mapping applications, and I encourage you to try them out. The explosion of mapping in the browser has only increased the importance of location for everyday users. Personally, when I’m out running errands, my phone keeps me updated as to how long it’ll take me to get home based on my current location and traffic conditions. That’s pure location-awareness in action.

GIS plays a large role in many areas of technology. Knowing the location of something can be critical in large asset-management systems that track construction and maintenance information of certain infrastructures, such as water and power. GIS is commonly used in crime analyses to help local law enforcement officials focus their resources. GIS is also used to project population growth in urban areas ...