DataBlade Module Development Overview Informix DataBlade Modules

The Informix Geodetic DataBlade module manages objects defined on the Earth's surface with a high degree of precision. It is designed to manage spatio-temporal data with global content, such as metadata associated with satellite images. To do this, the Informix Geodetic DataBlade module uses a latitude and longitude coordinate system on an ellipsoidal Earth model, or geodetic datum, rather than a planar, x- and y-coordinate system.

With the Informix Geodetic DataBlade module, you can extend your database server to store and manipulate objects in space, referenced by latitude and longitude. You can also provide additional attributes representing an altitude range and a time range.

You can create the following spatio-temporal objects with this module:

• Points
• Line segments
• Strings
• Rings
• Polygons
• Boxes
• Circles
• Ellipses

The Informix Geodetic DataBlade module provides three kinds of data types:

• Spatio-temporal. To represent objects.
• Distinct and range. Building blocks that simplify the construction and manipulation of spatio-temporal objects.

Spatio-temporal data types enable you to store data that represents spatial objects with a time component in an Informix database. The time component associates the object with a time period or moment in time. Spatio-temporal types are defined in a type hierarchy, with a supertype-GeoObject-that has the time and altitude attributes common to all spatio-temporal types.

Distinct types provide angular components such as latitude and longitude and linear components such as distance.

Range data types specify the altitude and time dimensions of spatio-temporal data.

The Informix Geodetic DataBlade module provides more than 60 functions to enable you to manipulate your spatio-temporal data. These functions can be grouped into the following categories:

• Accessor functions. These functions allow you to access information about objects stored in a database. For example, the Latitude function returns-or accesses-the latitude value of an object.

Type verification functions are included in this group.

• Computational functions. These functions perform standard computations.
• Constructor and conversion functions. These functions are the basis for the data types. Many of these functions are overloaded, with a conversion syntax in addition to a constructor. The conversion syntax converts an object from the GeoObject supertype back to its original representation.
• Spatial operators. The functions take spatio-temporal objects and test them for proximity or intersection. Spatial operators return Boolean TRUE or FALSE.
• Data validation functions. These functions verify GeoRing and GeoPolygon objects.
• System functions. These functions control session parameters and provide information about the version of the Informix Geodetic DataBlade module.
• Tracing functions. These functions control the trace files and tracing output.
• Warning functions. These functions control warning messages and output.
• Z Value functions. These functions manipulate Z values.

The Informix Geodetic DataBlade module also provides:

• a client utility called geovalidate that you can use to verify the correctness of your input data.
• support for the R-tree spatial access method. The R-tree access method allows you to create an index on columns containing spatio-temporal data.

For more information, see the Informix Geodetic DataBlade Module User's Guide.