OMNI Plot File Format

The plot file format from the National Geodetic Survey's PAGES program suite actually encompasses two files: the plot file itself and the limits file. The limits file was originally created to speed the appearance of some part of the plot on screen as an indication that the file(s) were being read. As computer processor speeds have increased and other, standardized tools have become available to indicate progress, the limits file has become unnecessary and Vupos does not make use of them. This format is called the OMNI for historical reasons. The plot file has two distinct sections: a header and the data. Fortran format codes are given with each value.

The OMNI plot file header, which spans the first few lines, contains

the Y-axis label (A)
number of stations (I5) and number of frequencies (I5)
station 1, frequency 1 plot title (A)
station 2, frequency 1 plot title (A)
   ·
   ·
   ·
station M, frequency 1 plot title (A)
station 1, frequency 2 plot title (A)
   ·
   ·
   ·
station 1, frequency 2 plot title (A)
   ·
   ·
   ·
station M, frequency N plot title (A)
Thereafter, the data are written in blocks. The first line of each block contains the epoch date and time, the number of satellites observed in this epoch and the satellite IDs using the format (5I3, F6.2, I3, 1X, I2, 58I3). The epoch is always the independent or X value for these plots. The next line, or in some rare instances lines, contains the actual dependent or Y values in the same order as the station/title listing given in the header, namely a loop over all stations inside a loop over all frequencies. The format (960E13.6) is used to write these values.
 YR MO DY HR MN SS.sss  N 01 02 … NN
 +.00000E+00 +.00000E+00 +.00000E+00 …  +.00000E+00
These blocks are repeated for all epochs.

Despite the fact that specific formats exist defining each line, considerable flexibility in writing these files has developed over time. However, the fundamental rule of staying within the indicated format space should be kept.

Two truncated examples of this format are given here. Note that each contains multiple plots in one file. The first is an a priori data processing plot file, which rigidly follows the format. It contains three plots in one file: the L1 frequency observations, the L2 and the ionosphere-free combination of L1 and L2. 

 DD A PRIORI (CY)
    1    3
L1        tnb1-mcm4 (aaab01)
L2        tnb1-mcm4 (aaab01)
ION FREE  tnb1-mcm4 (aaab01)
 98 12 10  0  0   .00  5  4  5 24 25 30
 -.679396E-02 -.679396E-02 -.381850E-02 -.358828E-02 -.358828E-02 -.201677E-02 -.478561E-02 -.478561E-02 -.268972E-02 -.611804E-03 -.611804E-03 -.343861E-03 -.186284E-02 -.186284E-02 -.104700E-02
 98 12 10  0  0 30.00  5  4  5 24 25 30
 -.255585E-01 -.473506E-01  .288636E-01 -.736340E-01 -.938130E-01 -.135666E-02.254248E+00  .325732E+00  .109758E-02 -.790955E-02 -.600692E-02 -.821975E-02  .338513E-01 -.309635E-01  .147598E+00
 98 12 10  0  1   .00  5  4  5 24 25 30
 -.233948E-01 -.407554E-01  .212889E-01 -.609865E+00 -.765481E+00 -.340776E-01 -.108205E+00 -.143559E+00  .931396E-02 -.477051E+00 -.582423E+00 -.590987E-01 -.363956E+00 -.495171E+00  .557319E-01
 98 12 10  0  1 30.00  5  4  5 24 25 30
  .315313E+00  .399576E+00  .100699E-01 -.854795E+00 -.113101E+01  .674824E-01.368703E+00  .454342E+00  .373479E-01 -.548905E+00 -.689278E+00 -.300532E-01 -.860545E+00 -.111965E+01  .303217E-01
 98 12 10  0  2   .00  5  4  5 24 25 30
  .802709E+00  .102208E+01  .159964E-01 -.996603E+00 -.130298E+01  .476211E-01.586772E+00  .761172E+00 -.161631E-01 -.548624E+00 -.676650E+00 -.543860E-01 -.107294E+01 -.137760E+01  .131826E-02
The second is from the ion.plt, which is the source for all the figures shown in the help information, and loosely follows the formatting. Note that this file contains two plots: the ionospheric residuals seen from the rover and a reference station. 
Ion Residual (cy)
    2    1
rover
reference
2003   3   4  16  54 40.000  5  4 20 28  7  8
       -0.838       -0.895       -0.975       -1.018        0.230        0.194     -0.448       -0.492        3.276        3.310
2003   3   4  16  54 41.000  5  4 20 28  7  8
       -0.834       -0.899       -0.977       -1.022        0.233        0.195     -0.453       -0.494        3.293        3.321
2003   3   4  16  54 42.000  5  4 20 28  7  8
       -0.833       -0.899       -0.987       -1.021        0.235        0.194     -0.455       -0.494        3.315        3.330
2003   3   4  16  54 43.000  5  4 20 28  7  8
       -0.836       -0.905       -0.994       -1.027        0.237        0.195     -0.457       -0.495        3.334        3.343
2003   3   4  16  54 44.000  5  4 20 28  7  8
       -0.835       -0.907       -0.996       -1.030        0.240        0.198     -0.459       -0.495        3.352        3.354

$Id: omni.html 24 2008-04-25 15:12:21Z mark $