You can use functions to generate spatial data from input
data.
Spatial data can be generated not only by geocoders, but by other
functions as well. For example, suppose that the bank whose branches
are defined in the BRANCHES table wants to know how many customers
are located within five miles of each branch. Before the bank can
obtain this information from the database, it needs to define the
zone that lies within a specified radius around each branch. A Db2® Spatial
Extender function, ST_Buffer,
can create such a definition. Using the coordinates of each branch
as input, ST_Buffer can generate the coordinates that demarcate the
perimeters of the zones. Figure 1 shows
the BRANCHES table with information that is supplied by ST_Buffer.Figure 1. Table that includes new spatial data derived
from existing spatial data. The coordinates in the SALES_AREA
column were derived by the ST_Buffer function from the coordinates
in the LOCATION column. Like the coordinates in the LOCATION column,
those in the SALES_AREA column are simulated; they are not actual.
In addition to ST_Buffer, Db2 Spatial
Extender provides several other functions that derive new spatial
data from existing spatial data.
