Geoprocessing is the act of manipulating geographic and related data. Esri's ArcGIS Desktop software provides a large number of geoprocessing tools that you can chain together into models to accomplish specific workflows, like the one you see in the following diagram. For example, you might create a model that buffers one layer and then clips a second layer to it. You could use the model with a stream layer for the buffer and a vegetation layer for the clip. But, having created this model once, you can use it to perform the same operations on other layers without having to recreate it from scratch. You could also automate it as part of a batch-processing operation.
But where things get interesting from our perspective as ArcGIS API for JavaScript developers, is the ability to publish these geoprocessing tools as services in ArcGIS Server and consume them within our web mapping applications.
Think about that for a moment. That means we can create just about any...