Title: Proposal for basic MeasurementSet conventions Person responsible: Bob Garwood (bgarwood@nrao.edu) Originator of proposal: Bob Garwood (bgarwood@nrao.edu) Exploders targeted: aips2-gbt, aips2-astro-design Time table: Date of issue: 1996 January 18 Done Comments due: 1996 January 24 Done Revised proposal: 1996 January 26 Done Final comments due: 1996 January 29 Done Decision date: 1996 January 31 Done Statement of goals: To establish some basic conventions for MeasurementSet columns These conventions cover the names as they appear in any table within a MeasurementSet, any associated comments, the names of non-predefined columns and the relationship of these to the FITS standard. Proposed changes: Note: PredefinedColumns is an enumeration currently describing all columns in the MeasurementSet (a single table). This is an implementation detail that may change as multiple tables are used within a single MeasurementSet (this change is covered in a separate proposal). These rules should apply to all columns in all tables within a MeasurementSet. The final implementation may require some fine-tuning of these rules. - The standard column names (PredefinedColumns): o The spelling of the individual PredefinedColumns enumeration will be exactly the same as the Strings used to name those columns in the MeasurementSet. o The names may consist of all upper case, alphabetic characters, all digits, plus the underscore and hyphen characters. No other special characters or lower case characters are allowed. o The names MUST be no longer than 68 characters (this allows the column name to be used as is in a FITS binary table). o It is strongly recommended that names be limited to 18 characters. - Comments: There is no limit to the length of an associated comment. - Column-associated keyword ( additional keywords are mentioned in other proposals) LABEL - This is a String keyword which indicates a label appropriate for this column (i.e. a more pleasing string than simply using the column name, with all caps and no spaces, etc). Additional "hints" keywords are likely but are not proposed here. - Consortium member specific columns Each consortium member is given a prefix (ATNF_, BIMA_, DRAO_, NFRA_, NRAO_, NRAL_, GMRT_). Each member will be responsible for control over names beginning with their prefix. Consortium members may add PredefinedColumns beginning with their prefix as they wish (after notifying the MeasurementSet czar of their intentions). - The non-standard columns All non-standard (not a PredefinedColumn) column names in a MeasurementSet must start with the prefix NS_ Expected Impact: The positive impact be that it should be easy to convert between a MS and a FITS binary table with no loss of information. It also imposes some naming conventions on the MeasurementSet and provides a useful way for consortium members to manage their own name-space. Non-standard columns are clearly identified as such and there is no danger that a future PredefinedColumn would be confused with some sites already existing non-standard column.