Book Image

Applying and Extending Oracle Spatial

Book Image

Applying and Extending Oracle Spatial

Overview of this book

Spatial applications should be developed in the same way that users develop other database applications: by starting with an integrated data model in which the SDO_GEOMETRY objects are just another attribute describing entities and by using as many of the database features as possible for managing the data. If a task can be done using a database feature like replication, then it should be done using the standard replication technology instead of inventing a new procedure for replicating spatial data. Sometimes solving a business problem using a PL/SQL function can be more powerful, accessible, and easier to use than trying to use external software. Because Oracle Spatial's offerings are standards compliant, this book shows you how Oracle Spatial technology can be used to build cross-vendor database solutions. Applying and Extending Oracle Spatial shows you the clever things that can be done not just with Oracle Spatial on its own, but in combination with other database technologies. This is a great resource book that will convince you to purchase other Oracle technology books on non-spatial specialist technologies because you will finally see that "spatial is not special: it is a small, fun, and clever part of a much larger whole".
Table of Contents (20 chapters)
Applying and Extending Oracle Spatial
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Table Comparing Simple Feature Access/SQL and SQL/MM–Spatial
Index

Adjusting coordinate dimensions


Some software products can create 3D SDO_GEOMETRY objects where the Z ordinate is NULL or 0. To use some of the Oracle Spatial processing functionality, the Z ordinate must be removed. While basic functions to do this are covered in the book Pro Oracle Spatial, variations are often needed. The following are introduced here:

Create Or Replace Type Body T_Geometry
[...]
  /* Dimensional Adjustment */
  Member Function ST_To2D Return T_Geometry Deterministic,
  Member Function ST_To3D(p_zordtokeep In Integer)
                          Return T_Geometry Deterministic,
  Member Function ST_To3D(p_start_z    In Number,
                          p_end_z      In Number,
                          p_unit In varchar2 default null)
                          Return T_Geometry Deterministic,
  Member Function ST_FixZ(p_default_z  In Number := -9999 )
                          Return T_Geometry Deterministic,

Reducing 3D to 2D – ST_To2D

One very tangible example of reducing...