GeoRegistration XML

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 pre-pending 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 real-world 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' elev-unit='m' />
          <!-- OR -->
    <geographic lat='y' lon='x' elev='z elev-unit='m' />
          <!-- OR -->
    <cartesian y='y' x='x' z='z' elev-unit='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 sub-elements of <axes/> are defaulted to the values above.
• The <scale/> element is not required and defaults to 1.0 along all axes.