DBF File

The DBF (*.dbf) format was created for early spreadsheet applications in the 1960s. It is used in the set of files that make up a shapefile, and can be used in SpaceStat to merge additional attribute data to a geography.

The DBF file has a header that defines the number of records, fields (names, type, length...) and several field or variable types (each field or variable would be termed a "dataset" in SpaceStat). Included below is a list of field types:

• character

• data

• numeric

• logical

• memo

• variable

• picture

• binary

• general

For SpaceStat, the most important types are character, date, and numeric datasets.  When a DBF is exported from SpaceStat, it will contain columns that show the start and end dates associated with the data, as well as "flags" (0 or 1) that indicate if these dates are inclusive (1 = "true").  These data columns facilitate the re-import of DBFs from one SpaceStat project to another, since the time stamping process will not need to be repeated.  

Representing dates

You can also use the date field type in the DBF file. This automatically stores the dates in the correct format for import into SpaceStat (YYYYMMDD). Alternatively, you can follow these temporal format guidelines.

Representing time

As there is no data type for time in the DBF format, you must use either the numeric format HHMMSS or string format HH:MM:SS to represent times.

Missing values

Cells cannot be empty in a DBF, you must specify a missing value code to substitute for "no data" or missing data cells. Otherwise, the file will not import properly.