Creating an Observation Using a Face1 or Face2 Angle
 
 
 
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Create an observation from a traverse station using a horizontal angle measured on Face1 or Face2 of your instrument.

You can then input the measurements, using the Face1 (direct) and Face2 commands. These commands apply collimation (if set), and automatically average the sightings after you input observations.

Face1/Face2 angles can be collected in any order. The only requirement is that the Face1 backsight be recorded first. If Face2 observations are recorded, then a corresponding Face2 backsight should also be recorded. In the case where Face2 foresight observations are recorded previous to the Face2 backsight, the Face2 backsight is assumed to be the Face1 backsight plus 180°.

AutoCAD Civil 3D uses all reciprocal observations to a point (both foresight and backsight) by calculating an average horizontal and vertical distance of all the observations as long as the distance is a non-zero value to calculate the average horizontal and vertical position of a point.

The correct average for all Face1/Face2 and reciprocal observations is applied when the [adjust] command is used. An adjustment may be done to get the correct average values whether there is a closed traverse or not.

Procedure
Creating an Observation Using a Face1 or Face2 Angle
Quick Reference

Survey Command Window Syntax

F1 (point) [angle] [distance] (description)

F2 (point) [angle] [distance] (description)

or

F1 VA (point) [angle] [distance] [vertical angle] (description]

F2 VA (point) [angle] [distance] [vertical angle] (description]

or

F1 VD (point) [angle] [distance] [vertical distance] (description)

F2 VD (point) [angle] [distance] [vertical distance] (description)

Parameter Definition
point The point identifier of the new point. You do not need to assign a point number if auto point numbering is on.
angle The measured horizontal angle. It is assumed to be clockwise (right). Use a negative number (-) to turn counter-clockwise (left). Type the horizontal angle in the current angular units (DMS, grads, decimal degrees, radians, or mils).
distance The distance from the instrument point to the point being located. It is measured in the current units unless otherwise specified. The distance is assumed to be a horizontal distance unless VA is used. When VA is used, the distance is recognized as a slope distance.
vertical angle The direction of the vertical angle (zenith, horizontal, or nadir). Type this value in the current angular units (DMS, grads, decimal degrees, mils, or radians).
vertical distance The elevation difference from the instrument to the prism. If the prism is higher than the instrument, then this is a positive value.
description An optional description associated with the point. If you use a description key, then specific information is assigned to the point.