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<DIV><FONT face=Arial size=2><SPAN
class=124094818-27112002>Hi,</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=124094818-27112002></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=124094818-27112002>I too have been
thinking about the content of the NXSample group and how to convey more
information about the sample. </SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=124094818-27112002></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=124094818-27112002>For example, the
definition of the unit cell is currently defined as a 6 element array, but there
is no indication of the order in which elements should be stored. Is it a, b,c,
alpha, beta, gamma? Or alpha, beta, gamma, a, b, c? Given that everything can be
stored sensibly using XML and the HDF format, it would be better to define each
of these quantities separately:</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=124094818-27112002></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=124094818-27112002><NXsample
name="whatanicesample"></SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN class=124094818-27112002><unit_cell>
</SPAN></FONT></DIV>
<DIV><FONT><SPAN class=124094818-27112002><FONT face=Arial
size=2> <length_a units="Angstrom" type="NX_FLOAT32">
{Unit cell a-axis
length}? </length_a> </FONT></SPAN></FONT></DIV>
<DIV><FONT><SPAN class=124094818-27112002>
<DIV><SPAN class=124094818-27112002><FONT face=Arial size=2>
<length_b units="Angstrom" type="NX_FLOAT32"> {Unit cell b-axis
length}?</length_b> </FONT></SPAN></DIV>
<DIV><SPAN class=124094818-27112002>
<DIV><SPAN class=124094818-27112002><FONT face=Arial size=2>
<length_c units="Angstrom" type="NX_FLOAT32"> {Unit cell c-axis
length}?</length_c> </FONT></SPAN></DIV>
<DIV><SPAN class=124094818-27112002>
<DIV><SPAN class=124094818-27112002><FONT face=Arial size=2>
<length_alpha units="degrees" type="NX_FLOAT32"> {Unit cell alpha
angle}?</length_alpha> </FONT></SPAN></DIV>
<DIV><SPAN class=124094818-27112002>
<DIV><SPAN class=124094818-27112002><FONT face=Arial size=2>
<length_beta units="degrees" type="NX_FLOAT32"> {Unit cell beta
angle}?</length_beta> </FONT></SPAN></DIV>
<DIV><SPAN class=124094818-27112002>
<DIV><FONT face=Arial><SPAN class=124094818-27112002><FONT
size=2> <length_gamma units="degrees" type="NX_FLOAT32">
{Unit cell gamma angle}?</FONT></SPAN><SPAN class=124094818-27112002><FONT
size=2> </length_gamma> </FONT></SPAN></FONT></DIV></SPAN></DIV></SPAN></DIV></SPAN></DIV></SPAN></DIV></SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=124094818-27112002></unit_cell></SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=124094818-27112002></NXsample></SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=124094818-27112002></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=124094818-27112002>Crystallographers
have already gone to great trouble to define a huge number of sample
specific properties, including the geometric location of sample faces, in quite
some detail. </SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=124094818-27112002></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=124094818-27112002>The current CIF
dictionaries (<A href="http://www.iucr.org/cif/">http://www.iucr.org/cif/</A>)
are exceedingly comprehensive, even dealing with storing raw and processed data,
and I believe there is a great deal of knowledge and wisdom that can be ported
over directly into NeXus. The CIF structures look as if they will port to
XML relatively painlessly, and additionally would make conversion of NeXuS
files to and from CIF a breeze.</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=124094818-27112002></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=124094818-27112002>My suggestion then
is that NeXuS should aim to incorporate the CIF definitions, or certainly a
large subset of them, into the NXSample class definitions.</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=124094818-27112002></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=124094818-27112002>Any
thoughts?</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=124094818-27112002></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=124094818-27112002>Regards,
</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=124094818-27112002></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=124094818-27112002>Martyn
Bull</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=124094818-27112002> </SPAN></FONT></DIV></BODY></HTML>