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

Moving/shifting lines parallel to the original object


A common requirement for spatial data processing is to move a linear object parallel to itself. Examples include the desire to create a linestring that is parallel to the boundary of a land parcel, as is the case with rights of carriageway, often defined as being 10ft from an existing boundary. Similarly, one often hears of the need to create a line parallel to an existing road centerline; perhaps to define the boundaries of the road reserve or to present linear data graphically adjacent to the existing data.

Shifting a line sideways – ST_LineShift

A common and simple solution for moving a line parallel to itself is to extract the first and last vertex in a linestring, compute a single offset at right angles to an imaginary line composed of these vertexes, and then apply this to all the vertexes in the line. This is called line shifting and is implemented in ST_LineShift.

Create Or Replace Type T_Geometry As Object (
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