Documentation on imstat

Task: imstat
Purpose: Calculate and plot map statistics
Categories: map analysis

  Imstat calculates statistics for images. These are the sum, mean,
  rms, maximum and minimum value of a region. Statistics can be found
  for profiles or planes, specified using the axes-keyword.
  The data can be converted to Kelvin, by using 'options=tb' and the
  beam keyword.
  Output can be written to the terminal, a log file, or a plot. The
  options keyword gives control over the plot.
  The plotheader can be suppressed by using options=noheader. An
  alternative title can be put on the plot by options=title. A useful
  combination is 'options=noh,ti,title', to get only the string 'title',
  instead of the full header.

Key: in
	Standard in keyword. See the help on in for more information.

Key: region
	Standard region keyword. See the help on region for more information.

Key: plot
  This selects which statistic will be plotted as function of e.g.
  velocity. Minimal matching is applied. The default is 'rms'.

   'sum'         Plot the sum
   'mean'        Plot the mean
   'rms'         Plot the rms
   'maximum'     Plot the maximum
   'minimum'     Plot the minimum

Key: options
  The options control the characteristics of the plot.
  Possible options are (minimal matching is done):

   'tb'          Convert the units to brightness temperature, using
                 the input for the beam keyword

   'noheader'    Do not write the header information, just the numbers,
                 producing an ASCII file for a plotting program
   'nolist'      Do not write the statistics to the screen/logfile
   'eformat'     Always use format 'e' instead of 'g' to write results

   'xmin,#'      Give lower x-value on axis
   'xmax,#'      Give upper x-value on axis
   'ymin,#'      Give lower y-value on axis
   'ymax,#'      Give upper y-value on axis
                 (for these four options the default is autoscaling)
   'title,#1,#2,#3' Put the string #1 at x-position #2 and y-position #3,
                 with positions measured in units of the coordinates
                 on the axes. If 'title' is the last option, the title
                 is put in the upper left hand corner.
   'style,#'     This selects the plot style.
                 #=connect means connect the datapoints
                 #=step means make one-bin wide connected horizontal
                 line segments
                 #=histo means bins are drawn as a horizontal line
                 surrounded by two vertical lines

Key: cutoff
  All datavalues below the cutoff are not used for the calculation of
  statistics. Give one real value, which may be followed by the string
  ',abs' to get a cutoff in the absolute value of the datavalues.
  Default is no cutoff.

Key: beam
  If options=tb is used, imstat calculates the sum divided by the sum
  of the beam to get the flux in the selected area, if the units of the
  input data are 'per beam'. This is then converted to Kelvin by
  dividing by 2k/lambda^2 * omega, where omega is found from the beam
  keyword.
  If the name of a dataset is given for 'beam', imstat assumes it
  contains a beampattern and sums the data in a region of the same
  size as the input region.
  Else, it assumes that 'beam' gives the major and minor axes of the
  beam in arcsec and it calculates the sum for a gaussian beam of that
  size.
  If 'beam' is omitted, but 'options=tb' was selected, the beam is
  found from the header (items bmaj and bmin). If neither is present,
  no conversion is done.

Key: axes
  This keyword gives the axis (for profiles) or axes (for planes) along
  which statistics are calculated. E.g. 'axes=ra,dec' means that
  statistics are found for ra-dec planes (irrespective of their
  orientation in the dataset). 'axes=vel' gives statistics of a velocity
  profile at each ra and dec position in the selected region.
  The default is to calculate statistics for each ra,dec plane as
  function of velocity.
  Possible values for are: 'rascension', 'declination', 'longitude',
  'latitude', 'glongitude', 'glatitude', 'velocity', 'frequency',
  'channel', 'stokes', 'x', 'y', 'z', 'a', 'b'. Upper case and
  capitalized versions and the string 'R.A.' are also recognized.
  Minimal matching is applied. One or two axes may be given.

Key: device
	Standard device keyword. See the help on device for more information.

Key: log
  If specified, output is written to the file given by log= instead
  of to the terminal.