Using RDODDA : Dump of skymap source point information



In this exercise RDODDA will be used to extract to the output file "Vel.dat" the time (UT), Vertical velocity, horizontal magnitude, horizontal Azimuthal angle, horizontal North-South component, horizontal East-West component, root mean-square error, velocity line of sight, line of sight RMS error, and Filter % of sources. The data is extracted from the *.vel files generated from the DDAV package and placed in flat column formated files for use with other packages.


Computer generated responses are given in Red, the required typed inputs are given in black, Comments are preceded by // and are in green. The <function> qualifier specifies keyboard function keys, e.g.




Refers to the enter or return key

Refers to the escape key

Refers to the F1 key … etc…..


Remember before starting the program, delete any Vel.dat file that exists, or rename it for archiving the data set. Otherwise RDODDA will not allow you to overwrite this file and report an error if this file exists.

In the DOS (VM) window, or from the command line enter the following;


C: \DDA>rdodda <Enter> // Start Program

Enter path and file name.

7010u06c.vel <Enter> // Enter filename

Specify Skymap=1, DDA.Vel=2, Q.C.=3 or

GDDA.Vel=4 ??

2 <Enter> // Select processing velocity data

0 = Choose parameter.

1 = Old Drift output.

2 = Select number of parameters.

3 = Select parameters and set SG error bars.

2 <Enter> // Select option to extract number of parameters

Select Statistical parameter.

1 = Mean of all velocities

2 = Standard Dev. of all velocities

3 = Median of all velocities

4 = Up. Quartile of all velocities

5 = Lo. Quartile of all velocities

6 = M.P.V of all velocities

7 = Least Sq. fit of all velocities

1 <Enter> // Select mean values for each parameter

Stop - Program terminated.


Result :

The file Vel.dat will be generated with the following format.


20.1031 -4.73 121.20 175.69 -116.59 …

20.1033 1.26 96.23 156.15 -84.88 …

20.1050 -1.07 96.82 142.05 -51.05 …

20.1053 -10.33 100.44 103.58 -25.00 …





Refers to decimal Universal Time.



Refers to Vertical Velocity Vz (m/s).



Refers to Horizontal velocity magnitude Vh (m/s).



Refers to the Horizontal velocity azimuthal angle of arrival Az (Degree).



Refers to the horizontal north-south velocity component Vns (m/s).



Refers to the horizontal east-west velocity component Vew (m/s).



Refers to least squares root mean square error.



Refers to the group Line Of Sight velocity (m/s).



Refers to the L-O-S RMS error.



Refers to the % number of sources kept after the filter option in DDAV has been used.

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