Visualization, Data Sharing and Metadata - Geographic Visualization: Concepts, Tools and Applications - page 266

Database

Meas.Unit

Theme

Universe

Variable
Group

nCube

Variable LocMap

Rate

Category

DATA

Figure 13.2 GBHGIS Data Documentation System: entities and relationships

data table itself - in a single table. Figure 13.3 shows the surprisingly simple database
structure. g data ent type defines the kind of entities which can exist in g data ent , while
g data legal rel defines what kind of relationships between them are allowed to exist in
g data rel . Holding all entities in the one table again simplifies program code and will also
assist in creating a planned search interface.

g_data_ent_type

g_data_legal_rel
(used only in
checking)

Thedatamap
coordinates directly
reference categories
to improve
performance

g_data_ent

g_data_map g_data_rel

g data rate summary

g_data_coord

g_data

g_data_rate

Figure 13.3 GBHGIS Data Documentation System: database implementation