SQL/SDA

SQL/SDA is a query language particularly designed for complicated multi-step spatial data analysis. It has two distinct features:

All the clauses of SQL are extented which provides more options for representing user's request related to spatial data analyses.
It is implemented based on client/server architecture. The client side provides a friendly interface by introducing visual constructs such as icons, listboxes and comboboxes, which makes the formulation of queries more easily, and reduces the possible syntactical errors.