Syntax

   @OGCGeometry(to_attribute, <ogcType>, <attrName>[, <ogcversion>[, <toPrecision>]])
   @OGCGeometry(from_attribute, <ogcType>, <attrName>[, <fromPrecision>])
   @OGCGeometry(<validationType>) 

Arguments

   <command>   
   
      Range: (from_attribute|to_attribute)   
      
      To specify whether to import or export the geometry of a feature from/to 
      an attribute.

   <ogcType>   
   
      Range: (wkb|wkt|wkbhex) 
      
      The string specifying the OGC format of the geometry.

   <attrName>  
   
      Range: String  
      
      The name of the attribute to have the geometry saved to or retrieved from 
      the feature.

   <ogcversion>   
   
      Range: (1.1|1.2)  
      
      When exporting (to_attribute), specifies which version of OGC to use. 
      Currently supported are versions 1.1 and 1.2; 1.2 includes measure 
      support. The default is 1.1.

   <toPrecision>
   
      Range: (SHORT_64|FULL_64|FULL_32)

      When exporting (to_attribute) to wkt, specifies the desired precision
      used when converting coordinates from floating points to strings.
      The default is SHORT_64.

   <fromPrecision>

      Range: (FLOAT_64|FLOAT_32)

      When importing (from_attribute) from wkt, specifies the desired precision
      used when converting coordinates from strings to floating points.
      The default is FLOAT_64.

   <validationType>  
   
      Range: (is_simple|is_valid)   
      
      The string specifying the type of validation query to be performed on the 
      input geometry.

Description

      Note: For a method of storing and retrieving geometry in an attribute 
      where the geometry is fully preserved (including measures and complex 
      chains involving arcs), see @Geometry. 

   This command is used to set, get or validate the feature geometry. In both 
   get and set cases, the OGC type can be set to either Well-Known Text (wkt), 
   Well-Known Binary (wkb), or Well-Known Binary encoded as hexadecimal digits 
   (wkbhex). Depending on the <command> string, the attribute given will be the 
   source or destination for the geometry of the feature. For the get and set 
   modes the validation type is irrelevant.

   OGC version 1.2 adds support for measures on geometries. In from_attribute 
   mode this means any measures given in the input (such as in POLYGON M) will 
   be put onto the generated geometry as its "default" (unnamed) measure. In 
   to_attribute mode if the input geometry has a default measure it will be 
   added to the output WKT or WKB.

      Note: In to_attribute mode, if the feature has no geometry, then the 
      resulting attribute will have a blank value, because the OGC 
      specifications provide no way to represent a "null" geometry. Conversely, 
      however, in from_attribute mode, if the specified attribute has a blank 
      value, then the feature's geometry will be left untouched and a warning 
      output.

   When using the validation type, all other options need not be specified. This 
   function can either validate geometry as being simple or not, or in a more 
   basic sense, whether it is a valid OGC geometry or not according to the two 
   options. If the geometry is invalid, attributes will be added to the feature 
   which describe where and why it is invalid. These attributes are as follows:
   
      _validateFailCoordX  X coordinate where the geometry is invalid
      _validateFailCoordY  Y coordinate where the geometry is invalid
      _validateFailReason  Failure case index (an integer)
      _validateFailReasonString  English description of the failure
   
   The possible values of _validateFailReason and their corresponding 
   descriptions are:
   
      0  Undetermined Error
      1  Repeated Point (Not currently implemented)
      2  Hole Outside Shell
      3  Nested Holes
      4  Disconnected Interior
      5  Self Intersection
      6  Ring Self Intersection
      7  Nested Shells
      8  Duplicated Rings
      9  Too Few Points
      10 Invalid Coordinate
      11 Ring Not Closed