[gdal-dev] Coordinate system transfromations in dxf driver

[Even Rouault]

Pero,

> I started with trying to solve ticket 5705, incorect ellipse reading
> when extrusion is [0,0,-1].

I've applied your patch in r33770 (with the addition of a test case that 
demonstrates it). Thanks

> 
> As always the easiest solution was looked last, that is RTFM. If you
> read dxf reference from autodesk you will see that everything is
> explained very well. Not all entities use OCS (object coordinate
> system, which is derived from extrusion vector). For ellipse its
> clearly stated, excerpt:
> ---
> Ellipse group codes
> Group codes, Description
> 10 Center point (in WCS). DXF: X value; APP: 3D point
> 20, 30 DXF: Y and Z values of center point (in WCS)
> 11 Endpoint of major axis, relative to the center (in WCS).
> 21, 31 DXF: Y and Z values of endpoint of major axis, relative to the
> center (in WCS)
> ---
> 
> Currently dxf driver blindly applies coordinate transformations to all
> supported entities, which is incorrect.

Are there other entites you identified to be incorrectly handled ?

> 
> Note that angles need to be corrected with respect to OCS (right hand
> rule with counterclockwise direction).
> 
> RTFM, bye

Not the most friendly way to say good bye IMHO...

Regards,

Even

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