$ gemmi sf2map -h
Usage:
  gemmi sf2map [options] INPUT_FILE MAP_FILE
  gemmi sf2map --check INPUT_FILE

INPUT_FILE must be an MTZ or mmCIF file with map coefficients.

By default, the program searches for 2mFo-DFc map coefficients in:
  - MTZ columns FWT/PHWT or 2FOFCWT/PH2FOFCWT,
  - mmCIF tags _refln.pdbx_FWT/pdbx_PHWT.
If option "-d" is given, mFo-DFc map coefficients are searched in:
  - MTZ columns DELFWT/PHDELWT or FOFCWT/PHFOFCWT,
  - mmCIF tags _refln.pdbx_DELFWT/pdbx_DELPHWT.

Option --check can take column name mapping as arg, for example:
  --check=dfc:FCALC,fosc:FOBS  (typically, use --check without an arg).
Possible keys are fwt, phwt, delfwt, phdelwt, dfc, fosc, fom, free.

Options:
  -h, --help           Print usage and exit.
  -V, --version        Print version and exit.
  -v, --verbose        Verbose output.
  -d, --diff           Use difference map coefficients.
  --section=NAME       MTZ dataset name or CIF block name.
  -f COLUMN            F column (MTZ label or mmCIF tag).
  -p COLUMN            Phase column (MTZ label or mmCIF tag).
  --weight=COLUMN      (normally not needed) weighting for F.
  -g, --grid=NX,NY,NZ  Minimum grid size.
  --exact              Use the exact grid size specified with --grid.
  -s, --sample=NUMBER  Set spacing to d_min/NUMBER (3 is common).
  --zyx                Invert axis order in output map: Z=fast and X=slow.
  -G                   Print size of the grid that would be used and exit.
  --timing             Print calculation times.
  --normalize          Scale the map to standard deviation 1 and mean 0.
  --mapmask=FILE       Output only map covering the structure from FILE,
                       similarly to CCP4 MAPMASK with XYZIN.
  --margin=N           (w/ --mapmask) Border in Angstroms (default: 5).
  --select=SEL         (w/ --mapmask) Atom selection for mask, MMDB syntax.
  --check[=cols]       Analyze map coefficient columns in MTZ file.
  --pow=P              Transform |F|^P instead of F. --pow=2 for Patterson map.
