Generally, numerical data should be stored in UTF-8 encoded plain text files. In order to make the data file self-descriptive, any data file must contain:
a header containing metadata
a values section containing the actual data
Guidelines for the values section:
Only basic 7-bit ASCII characters should be used in values section
Values in a row must be separated by a delimiter
Every row must end with a line break. Use your the default line break character of your operating system
The same delimiter structure and line ending must be used in all rows, also in the last row.
Allowed delimiters are
, ; : Space TAB
Preferred delimiters are
, ; :
Data can be structured either as
independent variable delimiter dependent var. (delimiter dep. var. etc.) line break character
or as dependent values on a grid. In the latter case, the structure of the grid must be specified in the header.
- Date-time values should be given according to ISO 8061 (e.g., YYYY-MM-DDThh:mm:ss, 2001-08-08T19:35:02). UTC should always be used (otherwise, it must be indicated in the header).
Guidelines for the header section:
- The header section must be clearly marked as such and distinguished from the values section. This can be done by marking its beginning/end, by using a special character (such as #) at the beginning of each line, or by specifying the number of header lines.
- The header section must as a minimum contain a line specifying the quantities given in the values section and their respective units, including the delimiters, plus information about author(s) of the file and a link to the license agreement.
- The header should contain: information about how, when and where the data have been acquired and processed, instruments used and their setup (basically, all information needed if the reader wanted to reproduce the measurement). A contact of one of the authors might also be useful.
- Error estimates can either be included in the header or the values section
- It is possible to link to external resources if metadata are too large for the header. In this case, DOI should be used.