# Thread: Surveying - Understanding How Face 1 and Face 2 Value Are Observed

1. ## Surveying - Understanding How Face 1 and Face 2 Value Are Observed

Hello all

I have trying to learn how to survey. I am not an engineer or work in surveying however I have access to a Trimble S8 Total station and i am trying to learn how to use it off my own back.

I was wondering if anyone out there in the community could explain how Face 1 and Face 2 angles are observed using a total station or theodolite for that matter.

Below is a diagram of how I think face 1 and face 2 observations are recorded.

Is This Correct.jpg

The picture on the left is an angle measured to target 1 in the forward face (face 1), in this case it measures 60 Degrees - I am happy with this.

The picture on the right shows the telescope reversed, so the instrument is now in the reverse face, face 2 (Blue line). The angle the instrument reads is still 60 degrees, but is now read from the opposite side of the circle. The instrument then sights back to target 1 (clockwise) but continues to increment the angle from 60 degrees.

Have I nailed it or shall I get my head examined?

Can someone confirm?

Thank you.

2. Here's a couple of training videos on the use of a Surveying Theodolite.

Operating a theodolite Part 1

Operating a theodolite Part 2

3. Thanks Kelly...

4. Thank you Kelly. This is a great demonstration of a surveying theodolite.

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