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

• 08-10-2017, 02:11 PM
christian Bendis
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.

[ATTACH=CONFIG]1963[/ATTACH]

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.
• 08-11-2017, 07:39 AM
Kelly Bramble
Here's a couple of training videos on the use of a Surveying Theodolite.

[B][URL="http://www.engineersedge.com/video/Operating-a-Theodolite-Part-1_v1702"]Operating a theodolite Part 1
[/URL][/B]
[B][URL="http://www.engineersedge.com/video/Operating-a-Theodolite-Part-2_v1703"]Operating a theodolite Part 2[/URL][/B]
• 08-24-2017, 02:16 AM
sandesh_bukate
Thanks Kelly...
• 04-06-2018, 11:53 AM
ahmetkultransplan
Thank you Kelly. This is a great demonstration of a surveying theodolite.
• 01-03-2019, 05:10 AM
petronextinternational
The terms "Face Left" and "Face Right" originally refered to which side of the telescope the vertical circle of a theodolite lay when the telescope was reversed by rotating it 180° about its tilting axis. It the vertical circle was on the left side of the telescope from the observer's point of view at the eyepiece, that was the Face Left position.