10 Supported data formats

The simplest form of input for FROG is an ASCII file.

The file may contain any number of rows, but is expected to have either two or three columns only. In the case where the file has two columns, the first is taken as the time axis, while the other is taken to be the data values. In the case of three columns, the third column is assumed to be the error in the data value and treated as such. For example,

  # This is a comment
  #
  681.464894  0.015 0.05
  681.469584  0.114 0.05
  681.470124  0.076 0.05
  681.470674 -0.030 0.05
  # An embedded comment
  681.471204 -0.053 0.05
  681.471754  0.000 0.05
  681.473544  0.105 0.05
  681.474084  0.022 0.05
            .
            .
            .
  681.616134 -0.067 0.05

columns starting with # or ! will be ignored by FROG as a comment.

FROG can also read FITS format files. These should consist of two HDUs: a primary one containing minimal headers, and a single extension of type BINTABLE containing the table data.

The BINTABLE may contain two, three or four column. In the case where the file has two columns, the first is taken as the time axis, while the other is taken to be the data values. In the case of three columns, the third column is assumed to be the error in the data value and treated as such. Finally in the case where the file has four columns the first is assumed to be an index number, while the second, third and fourth are the time, data value and data error respectively.

The FITS format read and written by FROG is interoperable with the Starlink TOPCAT application. However, it should be noted that the two applications ASCII file formats are incompatible.