VISPLOT VISPLOT produces plots of visibility data (amplitude, phase, closure phase, and/or closure amplitude) versus time, with the option of plotting model curves. The data are read from a MERGE-format file (formats 1 and 2 are accepted). Any graphics device supported by PGPLOT can be used for the plot (e.g., Tek, VT125, Grinnell, ARGS terminals; Printronix, Versatec, LaserWriter printers). Examples $ VISPLOT input = da193.c plotfile = /gr np=10 ut htlet=0.06 cscale = 30 modfile = point.mod / $ VISPLOT input = "0235.MRG" plot = PLOT.PLT/PRINTRONIX modfile = "0235.MOD" np=3 utm amp phase close bas=12,13 tria=123,134 / $ PRINT/PASSALL PLOT.PLT Parameters The input parameters are listed below, with defaults in brackets. The input file name (INPUT) must be specified; the other parameters are optional. End the list of parameters with a slash (/). File names: INPUT = "file" : the name of the input Merge-format file (must be specified). PLOTFILE = "device/type" : a PGPLOT graphics device specification for the plot; e.g., "/GRIN" for a Grinnell TV display, "VISPLOT.LIS/VPS" for a PostScript file. The default is logical name TEKTERM, which is defined in VLB:LOGIN.COM, and may be redefined with a VMS ASSIGN or DEFINE command, e.g., $ DEFINE TEKTERM "XAA0:/ARGS" MODFILE = "file" : (optional) the file name of a model file; if this is specified, the model visibility curves will be drawn in addition to the data points. For real experiments involving orbiting stations, the present version of VISPLOT may not plot the model accurately enough to allow proper comparison with the data. However, the for data generated by FAKE, the model calculation will be accurate (see "Limitations" noted below). VISPLOT Page 2 Plot control parameters: NP = n : number of plots per page [5]. MODEL = n : This parameter specifies the number of points at which to calculate the model. [Default 100, maximum 500]. LINEWIDTH = n : Linewidth for plotting [Default 1]. COLORS = c1,c2,c3 : PGPLOT color indices for grid, data, and model. [Default = 5,3,1 = cyan, green, white]. NOPLTMS = s1,s2 : Do not plot model for baselines or triangles involving specified station numbers (up to 2). NOTEXT Do not plot filenames for printer plots. ONEPAGE Plot closure phase following amp or phase plots without paging. Time-axis parameters: TIMEA units for time axis, one of 'UT', 'UTM' (UT modulo 24 hours), 'IHA', 'GST' ['IHA']. TIMEC units for time axis for closure phases, one of 'UT', 'UTM', 'GST' ['GST']. UT set TIMEA='UT' and TIMEC='UT' (overrides TIMEA and TIMEC). UTM set TIMEA='UTM' and TIMEC='UTM'. IHA set TIMEA='IHA' and TIMEC='GST'. When orbiting VLBI stations are included in the array and TIMEA='IHA', TIMEA is reset to whatever TIMEC is. The interferometer hour angle concept is not valid for baselines involving orbiting stations as such baselines do not vary modulo 24 hr and are not necessarily even periodic. In fact, UT is perhaps the only useful time coordinate in this case. GST set TIMEA='GST' and TIMEC='GST'. NOMOD24 (only effective when UT time scaling is selected) if specified, the UT time axis will be labelled in straight hours rather than modulo 24. UTMIN=hh.hhhh[,ddd] (def = minimum UT in dataset) UTMAX=hh.hhhh[,ddd] (def = maximum UT in dataset) UTMIN and UTMAX allow the user to select only part of the dataset for plotting (i.e., only those sections with UTMIN <= UT <= UTMAX), regardless of whether UT, UTM, IHA, or GST is selected). There are two ways of specifying UTMIN and UTMAX: (1) Straight hours; i.e., set "hh.hhhh" equal to the number of hours since 00:00 hours UT on the first day in the data set. Leave "ddd"=0. ("hh.hhhh" can be found by specifying NOMOD24 and UT only in a preliminary run.) Example: UTMIN=108 UTMAX=136 instructs VISPLOT to select only data between 12:00 on the fifth day in the dataset and VISPLOT Page 3 16:00 UT on the sixth day. (2) Modulo 24 hours; i.e. set "ddd" equal to the day of year on which UTMIN or UTMAX occur and "hh.hhhh" equal to the UT on that modulo 24 hours. Example: assume that the first datapoint (whether deleted or not) occurs at 17:23 on DOY 113 in the above example. Then UTMIN=12,117 and UTMAX=16,118 would also select only data between 12:00 on the fifth day and 16:00 on the sixth. Data-selection parameters: AMP plot amplitudes. PHASE plot visibility phases. CLOSE plot closure phases. CLOSEAMP plot closure amplitudes (logarithmic scale). If this option is specified, the program will ask if all closure amplitudes are desired (there may be a very large number). If you type "Yes", it will ask for the range of the log of the closure amplitude: type the lower and upper limits (usually symmetric about zero, e.g., -1.5, 1.5). If you type "No", for each plot it will ask for a specific set of baselines (eg 12,34,13,24 for closure amplitude (12*34)/(13*24) ), and the range. You can type a / instead of the range to get the default (i.e., that specified for the previous plot, or -1.5, 1.5 for the first plot). To get out of this mode, type either control-Z or "0 /" in response to the question. If no data type is given, AMP and CLOSE are assumed. Otherwise, only the types requested are plotted. BAS array of baselines to plot [All found in data]. TRIA array of closure phases to plot [All found in data]. BAS and TRIA array elements consist of numbers such as 13 or 134 for the baseline from station 1 to station 3 or the closure phase involving stations 1, 3, and 4. The station numbers must be in ascending order. Plot format parameters: ASCALE eg ASCALE=1.0 : provides an upper limit of the amplitude axis on all baselines. If ASCALE is omitted, each amplitude is scaled independently so that the maximum is on scale. PSCALE eg PSCALE=30.0 : in phase plots, vertical axis will run from -PSCALE to PSCALE [180.0]. CSCALE eg CSCALE=45.0 : like PSCALE for the closure phase plots; this parameter can be used to blow up the scale of the closure phase plot [180.0]. NTICKS number of ticks on the vertical scale for amplitudes [5]. HTPLOT height of each plot in inches [adjusted so NP fits]. MAXWID max width of plot in inches (<8) [8]. MINWID min width of plot in inches [4]. HTSCAL height of vertical scale on each plot [less than HTPLOT]. HTTICK length of short ticks [0.07]. HTLET height of letters and numbers [0.10]. PHTSCAL height of scale as a fraction of HTPLOT but only if VISPLOT Page 4 specified. Default is HTSCAL value. Useful if HTPLOT is not known beforehand. SETWID alter calculated width to fill SETWID inches (up to the maximum on the device; SETWID=0.0 sets MAXWID) The above parameters can be used for nonstandard plots. for example, for 10 baselines per page, MAXWID should be about 5 and HTLET should be about 0.07. Experiment and see what seems to work well. Limitations 1. The maximum number of stations is 20. 2. The calculation of model visibilities when orbiting VLBI observatories are included in the stations array is not very sophisticated. The subroutine to follow an orbit through time includes only the central force due to the earth with oblateness ("J2") corrections. Higher order earth terms, the sun, moon, etc. are not included. As a result, if data from real orbiting VLBI observatories is being plotted, the model and data may cease to agree after a few orbits. The subroutine is the same as that in FAKE, however, so for simulations the model computation in VISPLOT will agree with the "data". Program History Version 1.0: - new program (R. Craig Walker). Version 1.1: 1981 Nov 12 - phase plotting added and moved to 15 stations (RCW). Version 1.2: 1982 Apr 6 - misc bugs fixed (RCW). Version 1.3: 1982 Jun 14 - bug in SYSPLT fixed (TJP). Version 1.4: 1982 Jun 18 - Subroutines MODAP and MODCAL changed to make model visibility calculation using lookup tables. Also, definitions of the major axes of model types 2-5 redefined (see $ VHELP INTRO). Use colors for Grinnell plotting, add GRTERM in some places (SCU). Version 1.5: 1982 Oct 2 - Fix bug in PHSAMP and MODCAL (type for CTYPE). Change colors for Grinnell. Increase NCP to 10000. Add LINEWIDTH parameter (default thickness=1) (SCU). Version 1.6: 1982 Dec 15 - Fix bug in CLOSEAMP scales. Allow 8 character station names. Prevent attempt to look at 2 station closure phases. Add ASCALE, PSCALE, CSCALE (RCW). Version 1.7: 1983 Feb 11 - Add UTMIN, UTMAX, NOMOD24; add day of month to plot label (DLM). Version 1.8: 1983 Mar - On an interactive device, reduce number of queries for to one per page plotted; allow for erasure of text written over plot (DLM). VISPLOT Page 5 Version 1.9: 1983 Apr 1 - Fix bug which draws boxes when no closure amplitude exists (DLM). Version 2.0: 1983 Aug 3 - Extend to include version 2 files. Include W in version 2 files (DLM). Version 2.1: 1985 May 14 - Alter error bars on closure amplitude plots to reflect the nonlinearity of the LOG display (RCW). Version 2.2: 1986 Aug 28 - Increase from 15 to 20 stations (TJP). Version 3.0: 1986 Nov 17 - Change to use parameter input for file names (INPUT, PLOTFILE, MODFILE); also update the header comments to include retrospective version numbers (TJP). Version 3.1: 1986 Dec 3 - Fix program to plot vertical scale labels correctly when all baselines or triangles are not present. Introduce new parameters PHTSCAL, COLOR, NOPLTMS, NOTEXT, ONEPAGE and SETWIDTH (from A.K. Tzioumis 1986 April 28).