Hexagon Geospatial


ERDAS IMAGINE, the world’s leading geospatial data authoring system, supplies tools for all your Remote Sensing and Photogrammetry needs.
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Calculating geometric coordinates from HFA parameters

by ParthaR. on ‎07-28-2016 08:21 AM - edited on ‎08-11-2016 06:45 AM by Anonymous (372 Views)


In the instance where a user wants to calculate geometric coordinates from an arbitrary point in image data with HFA (Informations) parameters:

For Polynomial instances, should  the user calculate  using  MapToPixelXForm parameters?  ( Tab 001 )  Or
For multiple XForm (All Polynomial) instances, should the user calculate using MapToPixelXForm parameters? ( Tab 002 )


The user can use many XForm transformation nodes, and IMAGINE will apply each XForm one by one.

The Affine transformation (http://en.wikipedia.org/wiki/Transformation_matrix) contains the rotation part, shift part and scale part. The 2x2 matrix will be the rotation matrix (already multiplied by the scale), and the 2x1 vector is the shift part (already multiplied by the scale).

The HFA structure for Xform is IMAGINE's internal structure, and will keep updating its content. So the user should not directly use information from the Xform structure. The geometric model dll will understand the details. A geometric model dll can be customized so only the creator understands the Xform used in their DLL.