Getting to Know Web GIS. Pinde Fu

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СКАЧАТЬ 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 with certain groups (not with individual users), share with their organizations, or share with everyone—the public. This allows other users to see and access the items. ArcGIS supports a variety of sharing levels.

      Types of user accounts

      ArcGIS Online and ArcGIS Enterprise support anonymous users, public users, and organizational users. Anonymous users can access the content shared with the public, if an organization has enabled anonymous access. Public users have limited abilities when creating and sharing content. Organizational accounts have levels, roles, and privileges.

      ArcGIS Web GIS user types.

      There are two levels of organizational user accounts. Level 1 accounts are viewers only. Level 2 accounts can view, create, and share content. A role defines the set of privileges assigned to a member. ArcGIS defines a set of privileges for four default roles. Organizations may refine the default roles into a more fine-grained set of privileges by creating custom roles.

Privileges of anonymous users and default roles
Privileges	Anonymous users	Default roles
Viewer	User	Publisher	Admin
Use maps and apps shared with them.
Use demographics, elevation analysis, geocoding, and network analysis; join groups without update capability.
Join groups with update capability; use subscriber content, spatial analysis, and GeoEnrichment; create content and groups; share maps, apps, and scenes; edit features.
Publish hosted web layers; perform analysis.
Manage user accounts; manage organizational settings; create custom roles; set up enterprise log-ins; disable multifactor authentication on member accounts; manage credit budgets; view subscription status; create and own groups that allow members to update all items in the group.					СКАЧАТЬ В начало < 2 3 4 5 6 7 8 9 10 11 > В конец