[Qgis-user] Accuracy of geo aligned JPEGs exported from QGIS

[RKaplan]

I've developed an AutoCAD based application that imports geo aligned
image markers (blocks) into a plan using EXIF metadata from images taken
by GPS enabled cameras.

The base drawing consists of a JPEG image exported from QGIS (Chugiak
2.4.0 Windows XP 32, Windows 7 32 and Windows 7 64).  The images are
exported using various NAD27 State Plane CRSs.

We're running into a situation where, on some of our systems, the image
and world file generated by QGIS is off by up to 120'.  The same map and
data, exported on other systems, will be very close - within a few feet
of the camera image markers.

I've only been able to test this on a half dozen systems, but the only
ones that generate an accurate JPEG/world file are those running Xeon
based processors.

I'm wondering if there isn't some inherent difference in the floating
point processing of the Xeon based systems that accounts for this.

Has anybody else seen this phenomenon?

Thanks

Rick

Rick Kaplan
CAD Systems Administrator
 
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