Now that we know how web services work, it is time to get back to the Server. A GIS service is a web service, which has a geographic element. Many standards for GIS service were developed and are widely implemented; in this chapter, we will discuss and author Esri map services and some of the Open Geospatial Consortium (OGC) services.
In GIS, we usually deal with maps. Esri map services are GIS services that handle operations on a geographical map. You can publish a map as a map service and consume this service from any client that supports this type of service. Map services are widely used and are famous for their simplicity and portability. The map services authoring tool for Server is ArcGIS for Desktop; hereafter, it is called Desktop. You cannot create a map service without this product, Desktop doesn't have to be installed on the same machine as your Server—as long as they are on the same network, you are good.