About using ArcGIS Online services in web applications

ArcGIS Online services are a set of maps hosted by Esri that can help support your GIS work. You can add ArcGIS Online services as layers in your web mapping applications. To access ArcGIS Online services, you can make a connection to the server using Web Applications Manager. Advanced developers can also use the controls installed with ArcGIS Web Applications or one of the ArcGIS web APIs to add ArcGIS Online services.

This help book explains how to connect to ArcGIS Online services while building a web application in Web Applications Manager.

Setting the primary map resource in your web application

In web applications containing more than one map service, the primary map resource determines which service will supply the coordinate system and zoom levels of the map. You may have noticed that when you build a web application in Web Applications Manager, there is a drop-down menu labeled Use coordinate system of. The service you select here becomes the primary map resource. If you use Visual Studio to build your web applications, the primary map resource is a property of the Map control.

In general, you should set the ArcGIS Online service as the primary map resource. The only appropriate scenario to set a different service as the primary map resource is if the service uses the same coordinate system as ArcGIS Online services and is cached at scales that correspond to a sequential subset of the ArcGIS Online service scales.