DISTANCE                                                               DISTANCE



     The DISTANCE command is summarized as follows:

          DISTANCE is a data description command that measures distance in
          kilometers, miles, and feet between any two points on the CRT.
          Distance may be along a straight line or along a path, such as a
          road or a stream.  The beginning and end points of the DISTANCE
          measurement are identified using the crosshairs (cursor) on the
          graphics display terminal.


     The DISTANCE command is specified as follows:
     (* denotes parameters which can only be entered in a prompted mode)

          DISTANCE (type) (crosshair input)* (crosshair input)*


     The individual parameters of the DISTANCE command are described below:

          (type) is an option to specify the type of distance measurement.
          The user must enter either [A]irline or [P]ath.  AIRLINE measures
          tance "as the crow flies" between two or more points identified on
          the CRT.  PATH measures distance between two points along a discrete
          line segment or path.  Distance is calculated in miles, kilometers,
          feet, and nautical miles.

          (crosshair input) is where the user points with the cursor to the
          beginning and end points of the measurement.  Use of any key other
          than the space bar will terminate the command.


     The following is an example of use of the DISTANCE command:

           ENTER COMMAND
          ? DISTANCE
           Enter: [A]irline or [P]ath
          ? PATH
           Point to locations (hit anything except space to terminate)

           DISTANCE =      .1698 MILES
                           .2732 KILOMETERS
                           896.4 FEET
                         .15 NAUTICAL MILES


     The limitations of the DISTANCE command are as follows:

          -- Window must be set.

          -- If the PATH option is used, the shortest distance will be found.

          -- If the PATH option is used, only distance along discrete lines is
             found, i.e., you cannot cross segments.

          -- If the PATH option is used, it may be to the user's advantage to
             blowup the study area (see ZOOM).  This increases the tolerance
             range for finding and selecting points within a line segment.
