Changes between Version 12 and Version 13 of FDORfc39
- Timestamp:
- 06/25/09 12:16:26 (15 years ago)
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FDORfc39
v12 v13 29 29 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]. 30 30 31 This model has been adopted by MS SqlServer 2008 and PostGIS databases following the OGS syntax , like:31 This model has been adopted by MS SqlServer 2008 and PostGIS databases following the OGS syntax; see References [3], [4]. Example: 32 32 STRelate('T*F**F***') for 'Within' 33 33 34 Oracle supports Relate as well but in more readable form, like:34 Oracle also supports Relate and DE-9IM model but in more readable form; see Reference [2]. Example: 35 35 SDO_RELATE(... 'mask=touch+coveredby') = 'TRUE'; 36 36 37 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.38 37 39 38 == Proposed Solution == 40 39 41 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. 40 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. 41 42 Obviously generating valid strings for spatial operation combinations in DE-9IM form is not convenient for the user and this task must be accomplished internally by FDO. In turn, FDO will present the user the list of available named operators which can be combined in a bitmapped mask. 42 43 43 44 A number of changes in FDO are proposed: … … 157 158 == Test Plan == 158 159 160 - create a test datastore with various geometry types and various types of interaction. Good examples can be found in [1]. 161 - test Relate with invalid mask. Exceptions should be thrown. 162 - test Relate queries with just one spatial operator. The results should match those from queries with named operators (i.e. existing style) 163 - test Relate with different spatial operation combinations. Manually validate the results. 164 159 165 == Funding/Resources == 160 166