$BEG_SKIP


OVERVIEW:

This sample file contains data for a Bearing-Distance/Bearing-Distance
intersection problem based on horizontal distances and bearings. 

For this example, there are two points with known geodetic latitude and
longitude (points AAA and BBB) and one unknown point (CCC provided with an
approximate latitude and longitude). From each known point (AAA and BBB),
the known bearing and distance (to CCC) has been measured or is known.

By performing a 2D geodetic network adjustment (at an average project height), 
COLUMBUS can easily determine the position of the unknown point CCC. 

In this example, we have redundant observation data. We don't really need both
a bearing and a distance from each known station. Therefore, a least squares
result will be determined with redundancy (degrees of freedom) of TWO. The
standard deviation for each observation will influence the results.



DETAILED STEPS:

1) Start COLUMBUS and load this data file (BearDist2DGeoIntersection.txt). 


   **** Options Setup:
2) Enter the Options - Units dialog box and set the Active linear units to 
   be U.S. Feet.

3) Enter the Options - Datums dialog and set the datum to be NAD 83 if it
   is not already set.

4) Enter the Options - Global Settings Tab and set the 2D Height to be 
   6000.0 feet. If the bearings you are providing are average bearings 
   (PLSS bearings are usually average bearings between each corner), 
   then enable the Rotate Bearings option in this same dialog. If the 
   bearings are equivalent to an azimuth (based on true north), then do not 
   enable the Rotate Bearings switch.


   **** Adjusted the network
5) Set the View to be 2D Geodetic.

6) Select all stations to be included in the adjustment.

7) Select station AAA and BBB to be fixed in 2D.

8) Enter the Select Observations dialog, select all observations.

9) Start the network adjustment. The latitude and longitude of station CCC 
   should be:

   N  44-26-46.54310
   W 105-05-34.04538

10) Keep the adjustment summary window open and view the results (Adjusted
    coordinates, observations, etc.)


$END_SKIP




$STATION_TYPE_FOR_OBS
  2D_GEO

$DATUM
  NAD 83
  6378137.0
  298.257222101

$UNITS
  U
  D
  1


! Station AAA and BBB have known latitude and longitude
$GEO_COMPACT; AAA; 44.2620283; 0; -105.0534081; 0; 6000.0; 0; 0; 0; 6000.0; 0; 0; 0; 0; 0
$GEO_COMPACT; BBB; 44.26468378; 0; -105.0457644; 0; 6000.0; 0; 0; 0; 6000.0; 0; 0; 0; 0; 0
! Station CCC has an approximate latitude and longitude
$GEO_COMPACT; CCC; 44.2646542; 0; -105.0534044; 0; 6000.0; 0; 0; 0; 6000.0; 0; 0; 0; 0; 0


! Observation data (bearings and horizontal distances)
$BEAR_COMPACT; BBB; CCC; 89.21100000; 15.000; SW; 2641.60000; 0.66001
$BEAR_COMPACT; AAA; CCC; 0.03200000; 15.000; NE; 2659.95000; 0.66001