at least one field needed not only geometry
Field type: the type of data at this column index. Types can be:
- "C": Characters, text.
- "N": Numbers, with or without decimals.
- "F": Floats (same as "N").
- "L": Logical, for boolean True/False values.
- "D": Dates.
- "M": Memo, has no meaning within a GIS and is part of the xbase spec instead.