The breathe of spatial functions that PostGIS provides is too large to be covered completely in any book. We invite you to explore the rich PostGIS manual to learn about all the functions. In this chapter we cover the main relationship and relationship output functions you will commonly find in PostGIS for the core spatial types geometry,geography, raster, and topogeoms. Many of these functions you will also find in other spatial databases such as Oracle Spatial/Locator, SQL Server 2008, IBM DB2 Spatial Datablade, and SQLite SpatiaLite.
We describe the fundamental OGC spatial concepts that many of these functions are founded on. Some of the functions such as ST_DWithin are particular to PostGIS, but have parallels in Oracle Locator/Spatial SDO.Within_Distance, SQL Server 2008 , and IBM DB2.
We describe DE9IM intersection matrix model that many spatial relationships are founded and are fairly standard across all spatial databases. We demonstrate an example that exercises the confusing corner cases of this model. In the hopefully entertaining example of The house with a courtyard, a walkway, the front door and courtyard greeters we explore how we can determine the orientation of these objects relative to each other by using these functions.
We are working on second edition of PostGIS in Action 2ed for availability sometime in April 2015. Early purchase review (MEAP) is now available for Second Edition: All 17 chapters now available on MEAP with code and data download on PostGIS In Action Edition 2 Chapters. Each purchase includes all E-Book versions including E-book version of 1st edition.
PostgreSQL: Up and Running, 2nd addition came out in December 2014 in Print (both Hardcopy and E-Book). It is also available on Amazon
. The focus of 2nd edition is PostgreSQL 9.3-9.4 and the content has increased by about 60 pages from first edition.
© Leo Hsu and Regina Obe 2014