In many applications, GeoBase eliminates the need for expensive, 3rd party spatial databases.
GeoBase supports the
following query types as specified by the Open  geospatial Consortium:
- Spatial Measurements: Finds the distance between points, polygon area, etc.
- Spatial Predicates: Allows true/false queries such as 'is there a
residence located within a mile of the area we are planning to build
the landfill?'.
- Constructor Functions: Creates new shapes with an SQL query specifying the various points and lines that compose it.
- Observer Functions: Queries which return specific information about a shape such as the location of the center of a circle.
Using the DataQuery class, users are able to directly query GeoBase regarding the spatial features that lie under a given area, defined by a Rectangle. Methods
exist for querying the different spatial data types that GeoBase uses.
A data query returns an array of the matching spatial features.
In some cases it is possible to request that only features of a
given type be returned. For example: The user could use the mouse
to specify an area on a map, and then use DataQuery to request all
the freeways inside that area by passing the appropriate StreetType to the query method.
Other data query methods return the following:
- Polygons of the desired PolygonType. Polygons represent enclosed many-sided features such as lakes, airports or golf courses.
- Points of Interest, such as restaurants, banks or tourist attractions. This method does not allow for the specification of feature types.
- Lines, such as rivers or state borders. These are non-street features which are represented as lines when drawn on a map.
- StreetLinks, which represent segments of a street.
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Spatial Functions