[NeXus-committee] data array orientation

[Osborn, Raymond]

Mark,
While I think that is true, in the sense that transforming the data to, e.g., (hkl), does not depend on how the detector is oriented, it is not particularly helpful if you are doing some other processing of the data (or even just viewing it). When I look at a plot of data that contains the shadow of the beam stop, I would like to know which way is up to decide if I positioned it correctly. I am not going to read the depends_on chain in the NeXus file to work that out. 

Ray

> On Apr 26, 2018, at 10:09 AM, Koennecke Mark (PSI) <mark.koennecke at psi.ch> wrote:
> 
> Ben,
> 
> 
>> Am 26.04.2018 um 16:51 schrieb Benjamin Watts <benjamin.watts at psi.ch>:
>> 
>> Hi Everyone,
>>   When writing an image to an array, there is the age-old question of whether the first array element corresponds to the top-left pixel, or the bottom-left pixel of the image. Is there any convention in NeXus about which to use, or an attribute to specify? I don't find anything specific in the documentation. This has become an issue for me because I have been following one image orientation convention and another beamline has followed the other and now a user wants a switch in the data analysis software to flip the image. I would assuming that the first data element corresponds to the first element of each axis array and so the image orientation could be detected by looking at whether the values in the sample_y array were increasing or decreasing in value. But perhaps I am missing something?
>> 
> 
> my quick answer is that it does not matter anymore. You properly define offsets and vectors for the x and y axis of the detector in its depends_on chain 
> and you can transform to your hearts delight.
> 
> Cheers,
> 
>    Mark
> 
> 
>> Cheers,
>> Ben
>> _______________________________________________
>> NeXus-committee mailing list
>> NeXus-committee at nexusformat.org
>> http://lists.nexusformat.org/mailman/listinfo/nexus-committee
> 
> 
> _______________________________________________
> NeXus-committee mailing list
> NeXus-committee at nexusformat.org
> http://lists.nexusformat.org/mailman/listinfo/nexus-committee