Proposed New Format for Text File of Source Information

2009-10-20


General Form & Delimiter

The text file consists of line of delimited text. The delimiter is the semicolon (;) character. The fields and their ordering:

sourceName; groupNames; coordSystem; epoch; longitude; latitude; refFrame; convention; velocity;

A delimiter must be present for every field. Since there are nine fields, each line in the text file must have nine delimiters.


Handling of Leading and Trailing Whitespace

Whitespace (e.g., space character, tab character) at the beginning and end of lines is permitted but will be ignored. Likewise whitespace immediately preceding or following the delimiter is also permitted but will be ignored.

For example, the following two lines will be handled identically by parsers:

a b c;d;e;f;g;h;i;j;k;
   a b c ; d ; e ; f ; g ; h ; i ; j ; k ;  

Note that whitespace within a field, as in "a b c", above, is preserved.


Handling of Optional Fields

Optional fields are permitted (see Field Details Section, below). An optional field may be left unspecified. For this purpose unspecified means either that there are no characters present for that field, leading to consequtive delimiters (e.g., ";;"), or that the only characters in that field are whitespace characters (e.g., "; ;").


Fields Containing Multiple Values

Some fields are allowed to hold multiple values. The comma (,) character will be used to separate the multiple values. The same rules regarding whitespace apply here as in between fields -- i.e., that whitespace immediately preceding or following the value delimiter is ignored. The comma after the final value is not mandatory.

For example, the following lines all represent the use of multiple values in the second field and will be handled identically by parsers:

a b c; d1, d2, d3; e; f; g; h; i; j; k;
a b c; d1, d2, d3,; e; f; g; h; i; j; k;
a b c;d1,d2,d3; e; f; g; h; i; j; k;

Field Details

sourceName

Name of a source.


groupNames

The group, or groups, to which this source belongs.


coordSystem

The celestial coordinate system in which the later longitude and latitude fields are expressed.


epoch

longitude

An east-west angle.


latitude

A north-south angle.


refFrame

Reference frame against which velocity is measured.


convention

The convention used to relate emitted frequency, source velocity, and observed frequency.


velocity

The velocity of a source.


For the three velocity fields either all must be specified or none must be specified. In other words, if the velocity value is specifid, then the rest frame and convention must also be; parsers will not make assumptions about unspecified values here.
A recent email to alma-sw-ssr has suggested that none of NRAO's software expose the relativistic convention.


Examples

Minimalist. Uses default coordinate system and epoch and does not specify velocity.

J0433+0521;;;;04:33:11.095535;05:21:15.619420;;;;
J1119-0302;;;;11:19:25.3;-03:02:51.32;;;;

Explicit. Same data as minimalist, above, but with coordinate system and epoch stated in long form, and spaces for eye relief.

J0433+0521; ; equatorial; J2000; 04:33:11.095535; 05:21:15.619420; ; ; ;
J1119-0302; ; equatorial; J2000; 11:19:25.3;     -03:02:51.32;     ; ; ;

Full. All fields used; multiple values in those fields that allow.

Secret Source; Favorite Recipes, Private; equatorial; J2000; 12:34:56.789; 87.654321; LSRK; Optical; -987.6,0.0,123.45,;