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

INPUT_FILE must be either MTZ or mmCIF 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.


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  Grid size (user-specified minimum).
  --exact              Use the exact grid size specified by --grid.
  -s, --sample=NUMBER  Set spacing to d_min/NUMBER (3 is usual).
  --zyx                Output axes Z Y X as fast, medium, slow (default is X Y
                       Z).
  -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, similarly to CCP4
                       MAPMASK with XYZIN.
  --margin=N           (w/ --mapmask) Border in Angstrom (default: 5).
  --select=SEL         (w/ --mapmask) Selection of atoms in FILE, MMDB syntax.