Now that we have planned which services should be authored, we need to create the blueprint of the services and their design. Also, we have to decide what the underlying database design is, how the services will be authored, and what standards they will support. We will get to these technical questions in the coming pages. Note that we proposed two options in the planning stage, so we need to produce two designs. I usually use the Unified Modelling Language (UML) as a tool for designing GIS services, specifically the deployment diagram as it provides a good blueprint of the GIS services design. There are plenty of UML books out there if you want to get into it: my favorite is UML Distilled by Martin Fowler. As for the database design, we will use the entity-relationship diagram.