Getting to Know Web GIS. Pinde Fu
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Map visualization goes from 2D to 3D and virtual reality (VR)
With the increased client-side graphics processing power and the broader support of WebGL, Web GIS products such as ArcGIS Online and ArcGIS Enterprise can create and display thematic and photo-realistic 3D web scenes smoothly. Representing a big step from 2D online maps, 3D web scenes provide web users a more intuitive means to understand their data. 3D scenes are also important for indoor mapping, an ongoing trend in GIS. Even more intuitive than 3D, VR, such as ArcGIS 360 VR, allows users with certain visual wearables to immerse themselves into 3D city models by teleporting to static viewpoints and comparing different urban design scenarios. The immersive experience brings GIS data and geospatial understanding even closer to users.
Data source goes from static to real time and spatial temporal big data
Many elements in Web GIS are of a real-time nature, such as the incidents immediately reported by field crews or citizens using mobile devices, the concurrent measurements from sensor networks and smart cities. This massive amount of data presents challenges in real-time intake, processing, analysis, visualization, and storage. ArcGIS GeoEvent Server and the ArcGIS Trinity project utilize cluster computing and can ingest thousands and millions of sensor readings per second, process them, and store them in real time. Such products and research allow Web GIS to meet the requirements of the Sensor Web interface and the Internet of Things (IoT).
Web GIS becomes smarter and more intelligent
Map visualization is the first step toward data analysis. Online mapping becomes smart today. ArcGIS Smart Mapping can analyze the data automatically and suggest the best mapping style and the best defaults. This can help users, experts or novice, create beautiful and informative maps quickly. Web GIS goes far beyond mapping. ArcGIS GeoAnalytics Server can perform big data analysis using distributed computing, aggregate data in the context of both space and time, extrapolate new ideas from raw data, and bring superior intelligence to business decisions. More recently, Web GIS has started to use machine learning and artificial intelligence. For example, machine learning significantly improved the accuracy of online imagery classification. Artificial intelligence has been able to quickly identify the damaged locations from millions of facilities’ photos, and ensure the damaged facilities are repaired early.
Paths to building Web GIS applications
The tutorials in this book teach readers how to build Web GIS apps. The ArcGIS suite of Web GIS products offers many paths to this goal.
ArcGIS offers many ways to build web applications. The green lines in the figure highlight the technology presented in this chapter.
The previous figure presents the three basic tiers in Web GIS architecture and the generic workflow to build Web GIS apps:
The data tier (on the left side of the figure) contains formats that range from simple CSVs managed with Microsoft Excel to sophisticated geodatabases managed with enterprise databases. This allows you to create map documents, toolboxes, and 3D scenes in ArcGIS® Desktop software, especially ArcGIS® Pro.
In the middle tier of the figure, you can publish desktop resources to ArcGIS Online or ArcGIS Enterprise as several types of web layers and services. You can then add these layers and services to 2D web maps and 3D web scenes.
Options for the presentation (or client) tier on the right side of the figure are essential apps. Apps range from ready-to-use ones that can be configured without programming to custom ones that use various web application programming interfaces (APIs) or software development kits (SDKs) to meet special requirements.Start with ArcGIS Online
Cloud computing is based on the idea that many of the computing tasks that individual computers handle locally could operate more efficiently using huge computer centers connected through web technologies and provided as web-based services. Cloud GIS uses cloud computing technology to deliver GIS capabilities. This has helped users lower costs, reduce complexity, and quicken scalability.
ArcGIS Online (www.arcgis.com) is a cloud GIS. With ArcGIS Online, you can use and create web maps and scenes; access ready-to-use maps, layers, and analytics; publish data as web layers; collaborate and share maps; access maps from any device; and create apps from your maps. ArcGIS Online is a cloud GIS that provides the following services:
Infrastructure as a Service (IaaS): you can upload your data and publish web layers to ArcGIS Online and host them on the ArcGIS Online infrastructure, which sits on top of Amazon EC2 (Elastic Compute Cloud) and Microsoft Azure. In this perspective, you would use the ArcGIS Online infrastructure, such as storage, CPU, and bandwidth.
Platform as a Service (PaaS): you can build Web GIS apps without programming by using configurable apps or with programming by using ArcGIS® web APIs and ArcGIS® Runtime SDKs. In this perspective, you would use ArcGIS Online as a development platform for creating apps.
Software as a Service (SaaS): you can use the rich collection of basemaps, thematic layers, analytical capabilities, and the countless and ever-increasing number of apps that are hosted in ArcGIS Online and published by Esri and its user communities. These capabilities are provided as a service from the cloud.
Adoption of ArcGIS Online and its quality of service
Before organizations add cloud GIS to their enterprise architecture, they first must assess the quality of services (QoS) of the cloud GIS. The following main factors represent QoS:
Performance: How efficiently the system responds to user requests, usually measured in response time.
Scalability: The ability to support a growing number of users without dramatically reducing performance.
Availability: A measure of how often a system is accessible to end users, often measured in the percentage of time — for example, 99.99 percent.
Security: The ability to provide confidentiality and secure access by authenticating the parties involved, encrypting messages, and providing access control.
ArcGIS Online provides reliable and trustworthy services in the four aspects listed. Based on many servers in the cloud and the use of high-performance computing technologies, ArcGIS Online hosts tens of millions of content items, millions of registered users, and responds to thousands of requests per second with fast performance, high scalability and availability. You can monitor ArcGIS Online availability in its health dashboard (http://doc.arcgis.com/en/trust/system-status). ArcGIS Online follows a robust and effective framework to enforce security and protect user privacy. ArcGIS Online is certified as compliant with many federal and international security and privacy standards (see more information at http://doc.arcgis.com/en/trust/compliance/compliance-tab-intro.htm). Because of the benefits of cloud computing and because of its high QoS level, ArcGIS Online has been quickly adopted by numerous government and commercial organizations around the world, from local to national governments as well as oil and gas, education, healthcare, law enforcement, banks, retailers, and more.
Web GIS information model
ArcGIS Online and Portal for ArcGIS information model.
The ArcGIS Online information sharing model has elements that include users, groups, content, and tags.
Users can create and join groups.
Users sign in to create and share content items, which can be a large variety of data, layers, and web maps and apps.
Content items have tags. Tags are indexed so users can search and discover items more efficiently.
Users can keep information to themselves, share