[Nexus-developers] Transforms again

freddie.akeroyd at stfc.ac.uk freddie.akeroyd at stfc.ac.uk
Thu Dec 16 12:46:32 GMT 2010


I think we need to clarify the interpretation of distance in the CIF
scheme. In the nexus simple coordinate system the origin is taken at the
sample and "distance" is the total flight path length from the sample to
the component, with negative distance indicating a pre-sample component.
"distance" is thus not a simple "z translation" except for components
immediately prior to or following the sample. To provide a
"z_translation" we can either:

(1) define a separate "z_translation" attribute
(2) interpret "z translation" as "distance(component being placed) -
distance(previous component)"



> -----Original Message-----
> From: nexus-developers-bounces at nexusformat.org [mailto:nexus-
> developers-bounces at nexusformat.org] On Behalf Of Mark Koennecke
> Sent: 10 December 2010 15:25
> To: nexus-developers at nexusformat.org
> Subject: [Nexus-developers] Transforms again
> Hi,
> attached are updated XML example files for the various ways to express
> transforms for a triple axis
> spectrometer. I added transformation_type and vector fields for sgu
> sgl as an example for the specification
> of a general axis.
> Best Regards and a nice Weekend,
>            Mark Koennecke

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