This PLATON option may be used to get an overview over the dataset in reciprocal space in terms of resolution, data quality, completeness and missing data.
The feature requires a '.res' (or .cif) and a '.hkl' (or '.fcf') structured reflection file and is invoked via ASYM-VIEW on the PLATON opening window or CALC ASYM VIEW from the keyboard.
See ASYM VIEW MENU
Given the file asym.hkl and a file asym.ins with the following content:
CELL 0.7107 23.302 8.259 16.871 90.00 115.70 90.00
ASYM can be invoked with platon asym.ins followed by the instruction CALC ASYM VIEW. The graphics then looks like in Fig.1
Data completeness is an important issue for CCD and imageplate derived datasets.
A series of resolution rings is shown [sin(theta) / lambda)] starting at 0.50 in steps of 0.05. The red ring represents the 'critical' 0.6 (about 25 degrees for MoKa) minimum resolution level required for Acta Cryst papers.
Only a Hemisphere of data is shown. Friedel related reflections are averaged.
Reflections in the asymmetric section of the hemisphere are represented by 'L' for weak reflections, '*' for those with intensities > 10 sigma(I) or the number of sigma's. Symmetry related sections show a '+' for reflections with a symmetry related reflection in the asymmetric section.
'Blanc' areas either indicate missing reflections or sytematic absences. (Left out on the basis of the symmetry provided in the .res (or .cif).