Advice On geodetic=false And Oracle Spatial Geodetic Coordinate System and Rhumb Lines

(Doc ID 1531142.1)

Last updated on JUNE 12, 2017

Applies to:

Oracle Spatial and Graph - Version 11.2.0.2 and later
Information in this document applies to any platform.

Goal

There are references that the 'geodetic=false' parameter is being deprecated and shouldn't be used with Oracle Spatial Indexes,  but in some cases, this parameter appears to suit specific requirements.

Oracle Spatial geodetic coordinate systems are based on specifying vertices for points and all segments between points are assumed to be along Great Ellipsoids (or perhaps Great Circles in some cases).

For example, consider a case using sea charts from international sources covering the whole globe in a variety of projected coordinate systems, some of which are circum-polar.  This geographical variety of data calls for a conversion into a common global coordinate system but only a geodetic system instead of the desired WGS84.

The charts' boundaries though definitively do NOT run along great ellipsoids, but rhumb lines (loxodromes).  The application needs to allow for identification of chart extent polygons based upon a search point or search polygon. Using a spatial index with 'geodetic=false' for the chart extent provides a user the functionality that he is searching for, with search results based on loxodrome geography rather that great ellipsoid calculations.

Are there alternatives to his approach?

 

Solution

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