Oracle Spatial Data Option FAQ

$Date: 17-Oct-1999 $
$Revision: 1.2 $
$Author: Frank Naudé $

Topics

With this, representation of features (point, line or polygon) are stored in a single field within a table. A single Helical Hyperspatial code (HHCODE) is used to store the Euclidean spatial dimensions and additional data dimensional include depth, elevation, or time. The types of multidimensional data are restricted only in that they must be a numeric data type and have a bounded range. The HHCODE is generated through the recursive decomposition of dimensional space. Attribute data for specific multidimensional data is stored within columns of a table in the database. Access to the data for processing and manipulation is accomplished through extensions to Oracle PL/SQL.

        SVRMGR> REM # Create user MDSYS with admin option
        SVRMGR> connect internal
        SVRMGR> @?/md/install/mdsysid.sql

        SVRMGR> REM # Install MD catalog
        SVRMGR> connect mdsys/mdsys
        SVRMGR> @?/md/admin/catmd.sql

In Oracle, a HHCODE is a datatype used for both spatial indexing and partitioned point data.

More technical:

HHCodes are in effect Peano Codes, an implementation of Space Filling Curves. The multidimensionality aspect is the use of the Riemannian hypercube in conjunction with the space filling curve. What in effect has happened is that the Riemannian tensor matrix has been mapped by the space filling curve. This gives mathemetical credence to HHCodes and a lot more functionality then just data access. One more thing the HHcode encoding is not just Euclidean, Curvilinear and linear coordinates such as Lat, Lon, depth and time can also be mapped together. This creates Time varying voxels, (I suppose one can call them toxels).

Contributed: Herman Varma