On the base of analyzing the character and structure of the point, line, area symbols, a data structure of map symbol base which serves the symbolized output in digital mapping is put forward.
On the base of the type of the point cloud, the author puts forward"T"method on the scan linedata reduction, compares them with other methods of the data reduction.
The first iteration defines the architecture - is it manual or automated, is it centralized or distributed, is it on-line or batch, is it flat files or a relational database, etc.