station, uvmin, uvmax, ampmin, ampmax, phsmin, phsmax, docursor Plot visibility amplitudes and/or phases versus UV radius. EXAMPLE ------- 0> radpl "BONN" 0> This example plots baseline amplitude against UV radius, plotting all but the data in the first sub-array associated with BONN in green. BONN data is plotted in a different color to highlight it. Model data if present is plotted in red. If the display device has a cursor then interactive mode will be invoked after the initial display has been completed. PARAMETERS ---------- station - (Optional) The name of a station to highlight in the plot. If not given or given as an empty string "", no station will initially be highlighted. (Stations can be specified subsequently with the cursor). uvmin - (Optional) Default=0. The minimum UV radius to display. Unless changed with the mapunits command, the units are millions of wavelengths. uvmax - (Optional) Default=0. (0 specifies the whole range). The maximum UV radius to display. Unless changed with the mapunits command, the units are millions of wavelengths. ampmin - (Optional) Default=0. The minimum amplitude to display. ampmax - (Optional) Default=0. The maximum amplitude to display. If you want to set later arguments while keeping the default amplitude range set both ampmin and ampmax to 0. phsmin - (Optional) Default=-180. The minimum phase to be displayed (degrees). phsmax - (Optional) Default=+180. The maximum phase to be displayed (degrees). If you want to set later arguments while keeping the default amplitude range set both phsmin and phsmax to 0. docursor - (Optional) Default=TRUE. If the display device has a cursor but you don't want to enter the interactive cursor mode, make this FALSE. CONTEXT ------- This task is useful for getting an over-all look at the whole data set in one plot. By default it plots the amplitude of visibilities of all IFs versus radial distance from the origin of the UV plane. Optionally it can also be used to display visibility phases instead or in addition to the plot of amplitudes. See below for details. For each baseline, one point is plotted per IF. Where multiple spectral-line channels are selected from a given IF, the visibility is the average of those channels and is displayed at the corresponding mean UV radius. It is often possible to get a vague idea of how the map will appear from looking at this plot. Unresolved point sources appear as flat amplitude distributions. Resolved sources display one or more gaussian fall-off distributions. Multi-component sources beat against each other, modulating the gaussian fall-off. In some cases you may be able to get a better impression by running the alternate 'projplot' command. See help projplot for details. If the distribution is reasonably smooth, it is also possible to see the effects of poor calibration. The highlighting function is invaluable here. Highlighting each station in turn will eventually reveal the identity of a bad station or baseline. The 'S' option key described below provides a more direct way of identifying the origin of discrepant points. INTERACTIVE MODE ---------------- If your display device has a cursor, then there are a number of interactive options that you can use. These are selected by moving the cursor into the plot window, and pressing the following keys: X - Quit the radplot session, and return to the difmap prompt. L - Re-display the plot. . - Toggle the marker symbol used to display the data between the smallest available and the next largest. By default the smallest possible marker symbol is used for speed, but if if the data are sparse then the larger marker symbol may be more convenient. H - (Help) Briefly list all keyboard options. n - Highlight visibilities from the next telescope in the currently highlighted sub-array. Initially no telescope is highlighted. If this key then pressed, the visibilities of the first telescope of the first sub-array will be highlighted. Pressing this key again highlights the second telescope, etc.. When the last telescope of the current sub-array has been plotted, the first telescope of the next sub-array will be plotted. So by repeatedly pressing this key you will eventually have seen each telescope of all sub-arrays individually highlighted. p - This has the reverse the effect to the 'n' key, highlighting the visibilities of the previous telescope in the current sub-array, and wrapping back to the last telescope in the previous sub-array, after the first telescope of the current sub-array is highlighted. N - [Upper-case n] Similar to the lower-case 'n' key this key results in the first telescope of the next sub-array in the observation to be highlighted. In this way you can jump between sub-arrays without having to see all the telescopes of the intermediate sub-arrays highlighted one at a time. P - [Upper-case p] This has the reverse effect of the 'N' key, allowing one to directly step backwards through sub-arrays. T - To have a specific telescope of a specific sub-array highlighted without having to step through all the intermediate telescopes and sub-arrays, press this key. On the text window you will then be prompted for the name of the telescope to be highlighted. Telescopes are specified by an optional sub-array number delimited by a colon, followed by an unambiguous telescope name prefix. If the sub-array number and colon are omitted then the sub-array from which telescopes are currently being highlighted will be assumed. For instance, both 3:BONN and BON refer to a telescope named BONN in sub-array 3 if another telescope of sub-array 3 is currently being highlighted. Also, provided that sub-array 2 does not contain more than one telescope starting with the prefix JBN, 2:JBN is sufficient to refer to a telescope called JBNK1 in sub-array 2. S - This key invokes a report on the baseline and time of the nearest point to the cursor. The result is displayed on your terminal. The actual data point is unaffected. A - This key (left-mouse-button) flags the nearest data-point to to the cursor. Note that the preferred method for editing points is through the vplot command in station editing mode. Individual points should only be flagged in radplot if they are clearly singled out as being extremely bad, as opposed to being part of a group of bad points manifesting a bad telescope. If you delete too many points singly, rather than by station you may find that subsequent self-calibration will produce wild solutions due to incomplete or ambiguous un-connected closure triangles. C - This initiates cut area selection, through which a rectangular area may be selected within which to flag data. After pressing 'C' you will be expected to enter the locations of two opposite corners of the area, by pressing 'A' (left-mouse-button) over the corresponding points of the plot. To cancel a half selected area press 'D' (central-mouse-button). Once two corners have been selected, all visibilities displayed in that area will be flagged and will then disappear from the plot. W - Toggle the scope of edits with respect to spectral-line channels. Each point in the plot comes from a single IF, and its UV radius in the plot is determined by the mean frequency of the channels currently selected from that IF. By default, if you select such a point to be flagged, then all spectral-line channels of the source IF will be flagged, irrespective of the channels which actually went into making the plot. The alternative is to edit just the channels that went into making the plot. The 'W' key toggles which of the two options is used, and a mode line above the plot describes which option is currently in effect. U - Select a new UV-radius display range. Having pressed this key, you will be expected to either press it a second time to select the full available UV-radius range (and enable future autoscaling), or to select a new range by pressing the 'A' key twice, once at each of the two UV-radii that enclose the desired range. To abort the selection press the 'D' key (middle mouse button) and the display will remain unchanged. Z - Select a new amplitude display range. Having pressed this key, you will be expected to either press it a second time to select the full available amplitude range (and enable future autoscaling), or to select a new range by pressing the 'A' key twice, once at each of the two amplitudes that enclose the desired range. To abort the selection press the 'D' key (middle mouse button) and the display will remain unchanged. Display mode options. The following keys each change how the data are displayed. In order that you can change more than one attribute at a time, they may be grouped by pressing one key after the other. When you have speficied all the attributes that you want to, press the RETURN key and the display will be refreshed. M - This key toggles whether the model is plotted. Model amplitudes/phases are plotted as red dots. 1 - Only display amplitudes versus UV radius. 2 - Only display phases versus UV radius. 3 - Display both amplitudes and phases in vertically adjacent plots. + - This key toggles whether the cursor is shown as a small cross or as a cross-hair that extends the full width and height of the display. Currently only the /xserve and /xwindow PGPLOT devices support this feature. CONFIGURATION VARIABLES ----------------------- The display-mode option keys listed above may be preset in the variable, 'rflags'. If rflags is an empty string, "", then the default option string "m1" is substituted. This requests that the othrwise optional plotting of the model be selected by default and that only amplitudes be displayed. To override this default and have radplot start up by displaying both amplitudes and phases, on the command line one would type: 0> rflags="m3" If you always want to override the default, then place such an assignment line in your difmap login file (the file named in the optional DIFMAP_LOGIN environment variable). OTHER DISPLAY COMMANDS ---------------------- projplot - Display visibilities amp/phase vs. projected UV distance. uvplot - Display the sampling of the UV plane. vplot - Display observed and model visibilities from the current IF. tplot - Display the time-sampling of each telescope of the current IF. corplot - Display the self-cal corrections of the current IF. cpplot - Display observed and model closure phases interactively.