NAME:
  mkspace
 PURPOSE:   (one line only)
  Make spacing file for creating occultation tracks
 DESCRIPTION:
 CATEGORY:
  Occultations
 CALLING SEQUENCE:
  mkspace, ntracks, spread, [prefix], spacing=spacing
 INPUTS:
  ntracks  :Integer, number of tracks to generate
  spread   :Float,   spread of deployment in km
 OPTIONAL INPUT PARAMETERS:
  prefix   :String,  prefix to use before track number
 KEYWORD INPUT PARAMETERS:
  spacing  :Float,   space between tracks in meters
 OUTPUTS:
  A file is created with track names and cross-track positions in km.
 KEYWORD OUTPUT PARAMETERS:
 CONFIGURATION:
 COMMON BLOCKS:
 SIDE EFFECTS:
 RESTRICTIONS:
 PROCEDURE:
  If the SPACING keyword is provided, its value is used as the track spacing instead
  of the value inferred from SPREAD.
 MODIFICATION HISTORY:
  Written by Brian Keeney, Southwest Research Institute, August 2019
    2023-08-25, BAK: Modified to use the spread to drive spacing by default
    2023-10-23, BAK: Modified to create .info file for tracking purposes