[mapguide-trac] #1468: Unset the EPSG code when cloning a Coordinate System entity

[MapGuide Open Source]

#1468: Unset the EPSG code when cloning a Coordinate System entity
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   Reporter:  baertelchen  |       Owner:       
       Type:  enhancement  |      Status:  new  
   Priority:  low          |   Milestone:       
  Component:  General      |     Version:  2.1.0
   Severity:  minor        |    Keywords:       
External_id:               |  
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Description changed by brucedechant:

Old description:

> Currently, when calling one of the various CreateClone() methods in the
> Mg Coordinate System (CS) API, all of the entity's data is copied - incl.
> the EPSG code. This opens the door for inconsistencies, because the
> cloned entity becomes editable and can be saved to the dictionaries.
> Keeping the EPSG code creates a mess, because the underlying CsMap
> NameMapper component doesn't even consider the EPSG field in the
> dictionaries but does the mapping on its own.
>
> When assuming that a caller clones a CS entity to modify it, it's safe to
> unset the EPSG code because the underlying definition is about to change
> anyway and will thus no longer match the definition as defined by the
> EPSG.

New description:

 Currently, when calling one of the various !CreateClone() methods in the
 Mg Coordinate System (CS) API, all of the entity's data is copied - incl.
 the EPSG code. This opens the door for inconsistencies, because the cloned
 entity becomes editable and can be saved to the dictionaries. Keeping the
 EPSG code creates a mess, because the underlying !CsMap !NameMapper
 component doesn't even consider the EPSG field in the dictionaries but
 does the mapping on its own.

 When assuming that a caller clones a CS entity to modify it, it's safe to
 unset the EPSG code because the underlying definition is about to change
 anyway and will thus no longer match the definition as defined by the
 EPSG.

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Ticket URL: <http://trac.osgeo.org/mapguide/ticket/1468#comment:1>
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