Getting to Know Web GIS. Pinde Fu
has become more mainstream, and Web GIS awareness is growing more prominent in many organizations.
For government: Web GIS offers an ideal channel for sharing public information services and delivering open data, an engaging medium for encouraging public participation, and a powerful framework for supporting decision making.
For business: Web GIS helps create novel business models and reshape existing ones. It enhances the power of location-based advertising, business analysis, and volunteered geographic information, generating tremendous revenue, both directly and indirectly.
For science: Web GIS creates new research areas and renews existing avenues of research.
In daily life: Web GIS helps people decide where to eat, stay, and shop, and how to get from here to there.
ArcGIS is a Web GIS platform
Web GIS is central to Esri’s strategic direction for implementing GIS as a platform. ArcGIS represents a cutting-edge and complete Web GIS platform that enables users to easily discover, use, make, and share maps from any device, anywhere, anytime.
ArcGIS is a new generation Web GIS platform that provides mapping, analysis, data management, and collaboration.
At the center of this Web GIS pattern is a portal, namely ArcGIS Online or Portal for ArcGIS, which represents a gateway for accessing all spatial products in an organization. The portal helps organize, secure, and facilitate access to geographic information products.
Client applications on desktops, web apps, tablets, and smartphones interact with the portal to search, discover, and access maps and other spatial content.
In the back-office infrastructure, the portal is powered by two components: GIS servers and ready-to-use content.
Web GIS deployment models
The ArcGIS Web GIS platform offers three deployment models.
The online model uses only ArcGIS Online, the cloud-based Web GIS offering, in which all components are hosted in the public cloud. There is no hardware infrastructure for an organization to maintain because Esri manages and maintains ArcGIS Online.
The on-premises model uses only ArcGIS Enterprise. Organizations manage the hardware and software infrastructure by themselves to implement the Web GIS platform. ArcGIS Enterprise includes four software components: Portal for ArcGIS, ArcGIS® Server, ArcGIS® Data Store, and ArcGIS® Web Adaptor. ArcGIS Enterprise has additional server roles such as ArcGIS® GeoEventTM Server, ArcGIS® GeoAnalyticsTM Server, ArcGIS® Image Server, and ArcGIS® Business AnalystTM Server. Later chapters will have more details on these software components and server roles.
The hybrid model combines parts of the online-based model with parts of the on-premises model. Hybrid deployment is by far the most common Web GIS deployment pattern. Details of such a model depend on an organization’s business workflows and security requirements.
ArcGIS Web GIS platform can be deployed in three models. The dotted dash line represents the boundary between Esri-owned infrastructure and customer-owned infrastructure.
Compared to ArcGIS Enterprise, ArcGIS Online provides more ready-to-use contents, such as ArcGIS® Living Atlas of the World, and more ready-to-use-analysis services that are supported by these contents. ArcGIS Enterprise with its various license roles allows users to create more types of services than ArcGIS Online can create. But in general, ArcGIS Online and ArcGIS Enterprise share similar capabilities and similar workflows for creating services, web maps, and web apps. The tutorials in the book apply to both ArcGIS Online and ArcGIS Enterprise unless specifically stated.
Technology evolution and trends in Web GIS
Since its inception, Web GIS has been coevolving with geographic science and information technology. These evolutions and trends will be discussed in greater detail in later chapters.
ArcGIS Web GIS platform coevolves with geographic information science and information technology.
Web GIS has exemplified the following evolution of stages and trends in technologies:
From closed websites to open geospatial web services
Early Web GIS applications were developed as independent websites. These websites were isolated from each other. It was difficult to share information and functions between them, and difficult to remix the websites to create new applications. In the later 1990s, web services technology was conceived. Web services can be thought of as building blocks that can be shared and remixed in versatile ways for building web applications. The GIS industry adopted the concept of web services in manufacturing Web GIS products. For example, ArcGIS Web GIS products fully support the web services architecture: server side provides ready-to-use services and allows users to create their own services; client side can consume and combine these services to create applications.
From one-way to two-way information flow
Early Web GIS products and applications mainly supported one-way information flow, which was from server side to client side. Users were merely the receivers of information. As time entered the new century, user-generated content (UGC) became a significant phenomenon and created a reversed information flow, from client side to server side. Volunteered geographic information (VGI) is the UGC of a geospatial nature and this was supported by Web GIS products. For example, ArcGIS facilitates VGI through editable feature services and hosted feature layers, mobile GIS apps, and browser-based apps. Users can view maps and perform queries, as well as conduct field surveys, collect data, and report events they saw. VGI provides unique values and perspectives to global observation, information sharing, and public engagement.
Portal technology is becoming essential
The word “portal” means gate or entrance. It was adopted in the mid-1990s to form new terms such as “web portals,” referring to websites that serve as the gateway to other websites. Geoportals are gateways to geospatial information. They serve as the gateway or bridge between Web GIS servers and clients. Portals have become a core component of Web GIS technology. For example, ArcGIS Online and Portal for ArcGIS have geoportal capabilities. They facilitate the management, search, discovery, configuration, security, and remix of GIS data layers and services. Today, portals of different organizations can collaborate as hosts and guests, creating a “portal of portals” by using a distributed Web GIS pattern.
Cloud GIS accepted as the primary way to deliver GIS functions and ready-to-use contents
Cloud GIS, utilizing public and private cloud computing to provide GIS software and contents, has become the primary way to deliver GIS, not just functions, but also contents. Because of the vast contents and functions available from cloud GIS, the flexible pay-as-you-go or subscription-pricing model, and the reduced complexity and increased availability of services, cloud GIS, such as ArcGIS Online, has penetrated organizations that have not used GIS before or been able to afford GIS on their own.
Mobile is becoming the pervasive Web GIS client platform
As we entered the post-PC era, mobile devices have surpassed desktops and notebooks as the primary platform for accessing online information. Mobile devices are a part of people’s life and work. “Mobile First” was one of the strategies of many industries, including the Web GIS industry. Vendors have given extra attention to mobile GIS. For example, Esri provides numerous mobile native apps and mobile-friendly browser apps to support people’s and organization’s need for mobile GIS. Mobile GIS is also associated with many frontiers in Web GIS, such as augmented reality (AR). AR can superimpose GIS data on top of a user’s camera views and thus can augment a user’s sense of reality. With the rapid advances in mobile GIS, the vision of using GIS for anything, anytime, anywhere, and by anyone is being realized faster