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14.2 $ uv$ data plots

A procedure is available to do various plots from a continuum or line table. Its name is UVALL and it is called by clicking on ``Interferometric UV operations'' in the GRAPHIC standard menu. One has to select the first and last channel to be plotted (0 0 to get all channels) and the name of the parameters to be plotted in abscissa and ordinate. The following examples are the most useful plots:

$ uv$ coverage:
to get an idea of the imaging quality that may be obtained, to check if one configuration has been forgotten, ...

Figure 14.2: Example of a $ uv$ coverage plot
\resizebox{14.0cm}{!}{\includegraphics{rl3f1r.eps}}

weight vs. number:
check if some data got strange weights (e.g., zero) for any reason

Figure 14.3: Weight versus visibility number plot
\resizebox{14.0cm}{!}{\includegraphics{rl3f2r.eps}}

Amplitude vs. antenna spacing:
quite useful if a source is strong to see if it looks resolved. Also check for spurious high amplitude points.

Figure 14.4: Amplitude versus antenna spacing plot
\resizebox{14.0cm}{!}{\includegraphics{rl3f3r.eps}}

Amplitude vs. weight:
another useful check: spurious high-amplitude points with non-negligible weight can cause a lot of harm in a map.

These plotting facilities are also implemented in the MAPPING program as a command (SHOW UV).


next up previous contents
Next: 14.3 Data editing Up: 14. Plane Analysis Previous: 14.1 tables   Contents
Anne Dutrey