The purpose of this .xml file is to define what the model/document coordinates represent and to define the relationship of the model/document to the real world. Both 3D models and 2D documents can be GeoRegistered with the information in this file. The elements in <axes/>
define the former and the <points/>
define the latter.
There are three coordinate system types that the model/document can represent. Each .xml file may represent only one type coordinate system, either Projected, Geographic or Cartesian. As the document/model's axes may not be aligned correctly with the real world, the .xml file can specify which model/document axis represents what real world axis. Additionally, the axes definition can indicate if the model/document's values are inverted by prepending a minus sign ('') to the axis name for that system's mapping.
At a minimum, the <axes/>
element must contain an empty element indicating what the point representation will be such as <projected/>
.
The model/document's points may also be scaled to the real world. You can define what that scaling factor is using the <scale/>
element.
After the coordinate system type and mappings are defined, the registration points can be properly interpreted to GeoRegister the model/document. The contents of the <points/>
element provide the mapping of model/document values to real world values. Each <point/>
element contains a mapping pair for an individual point.
The realworld coordinate system type must match the one defined in the <axes/>
element and the model/document point indicates if it is a 3D or 2D source.
Currently, a 3D GeoRegistration may include only one point. This point defines the translation of the model to the real world.
A 2D GeoRegistration must have at least two points and may have more. If there are more than two points on a 2D GeoRegistration, they are fit using a least squares method.
The snippet below provides all possible .xml elements:
<georeg version='1.0'> <axes> <projected northe='y' east='x' elev='z' elevunit='m' /> <! OR > <geographic lat='y' lon='x' elev='z elevunit='m' /> <! OR > <cartesian y='y' x='x' z='z' elevunit='m' /> <scale x='1.0' y='1.0' z='1/0' /> </axes> <points> <point> <projected north= east= elev= /> <! OR > <geographic lat= lon= elev= /> <! OR > <cartesian x= y= z= /> <model x= y= z= /> <! OR > <document x= y= /> </point> </points> </georeg>
Notes:

<projected/>
,<geographic/>
, and<cartesian/>
are mutually exclusive and the element type in<axes/>
must match the element type of the<point/>
. 
<model/>
and<document/>
are mutually exclusive 
All subelements of
<axes/>
are defaulted to the values above. 
The
<scale/>
element is not required and defaults to 1.0 along all axes.
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