Let’s now move to the specifics of the storage and manipulation of spatial data based on Esri software. Esri is decades old and both its computer programs and storage schema have evolved considerably. As mentioned, the original, elegant data model—the coverage—that is based on using arcs to represent linear and areal features is virtually obsolete. You should know how to convert coverages (which you may come across because a lot of data sets are in this format) to geodatabases, but that’s all you will need to know. You may recall that making this conversion was presented in Chapter 1.
Geodatabases are the current “coin of the realm” in Esri software. All the tools being developed deal with geodatabases. A plethora of topology rules and topology fixes accompany geodatbases. Ideally, all coverages and shapefiles would be converted to geodatabase form. However, that is a monumental undertaking, of which, if you continue in the GIS field, you may be a part.
Sets of spatial data in Esri are primarily stored in geodatbases, shapefiles, TINs, (and “super TINS” called Terrains). The interactions among these types are fairly complex. Let’s start with the primary ways to store spatial data based on vectors and rasters: geodatabases.