The ArcGIS REST API defines the formats for JSON data objects commonly used by the system. The ArcGIS API for JavaScript uses this format to communicate with the server. When you look at the network traffic in your browser's developer console, you'll see these common JSON objects in both the requests and responses. Let's look more closely at two of these JSON object definitions: geometries and symbols.
Geometry JSON is a common data format used for ArcGIS Server processes. It makes sense, since finding geographic locations relies on geometry. Geometries come in a variety of shapes and sizes.
As mentioned in previous chapters, spatial reference refers to the calculations that represent the earth on a map, either as a spheroid (almost a sphere), or as a 2-dimensional representation of a land surface. Instead of documenting all the possible factors that go into calculating a spatial reference, a general format is followed, either by using an assigned...