Changes between Version 11 and Version 12 of FDORfc39

Timestamp:

Jun 25, 2009, 10:09:36 AM (15 years ago)

Author:

danstoica

Comment:

--

FDORfc39

@@ -23 +23 @@
 == Overview ==
 
-This RFC is for adding spatial operator combinations support.
+This RFC is for adding spatial operator combinations support (the RELATE spatial operator).
 
 == Motivation ==
 
-Allows implementation of the RELATE spatial filter.
+Along with the standard named spatial operators which FDO already suppotrs, OGS specifies the Relate predicate based on the pattern matrix which has the advantage that clients can test for a large number of spatial relationships and fine tune the particular relationship being tested; This pattern matrix is called the Extended Nine-Intersection Model (DE-9IM); see Reference [1].
 
+This model has been adopted by MS SqlServer 2008 and PostGIS databases following the OGS syntax, like:
+      STRelate('T*F**F***') for 'Within'
+
+Oracle supports Relate as well but in more readable form, like:
+      SDO_RELATE(... 'mask=touch+coveredby') = 'TRUE';
+
+Therefore supporting Relate implies providing the ability to generate DE-9IM strings based on a OR mask . Note it is not possible to generate an unambiguous OR mask given a DE-9IM string.
 
 == Proposed Solution ==
+
+Obviously generating valid strings for spatial operation combinations in DE-9IM form is not easy and this task must be accomplished by FDO. In turn, FDO will present the user the list of available named operators which can be combined in a bitmapped mask.
 
 A number of changes in FDO are proposed:
@@ -153 +162 @@
 
 == Referencies ==
-[1] [http://portal.opengeospatial.org/files/?artifact_id=18241] - Extended Nine-Intersection Model (DE-9IM) [[BR]]
+[1] OpenGIS® Implementation Specification for Geographic information - Simple feature access - Part 1: Common architecture - Extended Nine, 6.1.15.2 The Dimensionally Extended Nine-Intersection Model (DE-9IM) [[BR]]
 [2] [http://download-west.oracle.com/docs/cd/B19306_01/appdev.102/b14255/sdo_operat.htm#i78531] - Oracle SDO_RELATE() operator[[BR]]
 [3] [http://msdn.microsoft.com/en-us/library/bb933915.aspx] - SqlServer2008 STRelate() operator[[BR]]