This guide provides an introduction to using ArcGIS Online. ArcGIS Online enables the creation of web maps, web applications, and geospatial analysis projects to communicate with broad audiences related to spatial topics.
"ArcGIS Online is an online, collaborative web GIS that allows you to use, create, and share maps, scenes, apps, layers, analytics, and data." ArcGIS Online enables users to access geospatial layers from worldwide locations, create new content, and connect layers across the ArcGIS platform. In addition to web maps, applications are able to be created from configurable templates for enhanced user experience.
"In ArcGIS Online, a Web based, interactive map that allows you to display and query the layers on the map. A Web map contains one or more ArcGIS Server map services that are referenced to ArcGIS Online."
"A map depicting background reference information such as landforms, roads, landmarks, and political boundaries, onto which other thematic information is placed. A basemap is used for locational reference and often includes a geodetic control network as part of its structure."
"The visual representation of a geographic dataset in any digital map environment. Conceptually, a layer is a slice or stratum of the geographic reality in a particular area, and is more or less equivalent to a legend item on a paper map. On a road map, for example, roads, national parks, political boundaries, and rivers might be considered different layers."