Resection

Resection is used when setting up a Total Station on an unknown point.  The occupied point coordinates are calculated from two or more angle and distance measurements to known reference points.  This command only applies to total stations.

The dialog above has options for EDM Mode and Robotics.  These options will only show up for supported total stations (ie. robots, etc).

Configure Std Errors can be used to set standard errors for the measurements, as shown below.  These settings allow you to take advantage of network least squares and weighting in the resection calculation.  The default values are shown below:

Reference points are distinct known points that are measured to calculate the unknown occupied point.  Direct and Reverse measurements are optional by using the toggle Direct and Reverse located in the Add Reference Point section.

Reference points can be specified in several ways:

1. Manually entered point number
2. Selected from a list of points stored in the coordinate file (via List button)
   
3. Picked from the CAD screen (via Pick button)
4. Manually entered coordinates (via Create button)
   

There are input boxes for the target (or rod) height, and instrument height.  The Store Picked Points toggle controls whether or not the user is prompted to store screen picked points that are not found in the coordinate file.

After a reference point is chosen, it's description and coordinate information are displayed.  Press the Read button to initiate the measurement for the currently displayed reference point.  After a successful measurement, the user will be prompted to verify the measurement information.  This gives the user a chance to verify the target (or rod) height, and the option to discard the data and take another measurement.  The user will be prompted to determine whether or not to zero the instrument on the first reference point.

A minimum of two distinct reference points and measurements are required to calculate the occupied point.  The calculated occupied point information is displayed in the Resection Results section.  The input data is displayed in a list structure and the user has the option to turn certain measurement on or off using the On/Off button or remove an unwanted measurement using the Remove button.  The resection results are calculated automatically anytime a reference point measurement is added, a list item is removed, or a list item is toggled on or off.  A resection with three inputs 'on' and one input 'off' is displayed below:

The Resection Results section shows the calculated occupied point's northing, easting, and elevation and the difference between the calculated coordinate and the individual solutions as the residuals.  The residual indicate the quality of the data.  High residuals suggest a problem with the input data.  When you press the OK button, you will be prompted to verify the calculated occupied point.  If accepted, the calculated point will be stored to the coordinate file and you will be setup on the calculated point backsighting the first point shot in the resection.