Occupation & Backsight

This article will cover how to perform the Occupation & Backsight survey workflow while using Collage Site.

Occupation & Backsight is a traditional survey workflow for localization in which the instrument is set up on top of one known control point and its height is measured to establish a position. Then, the second known point is measured using a prism or other target to establish orientation.

  • The position of the instrument is determined by entering the known point’s coordinate value and measuring the height of the instrument above the point.
  • The orientation is determined by measuring a second known point away from the instrument. This second point can also be used to check the position of the instrument.

After having created a new station, choose the Localize option from the right side of the screen. Then, choose the Occupy & Backsight option.

If no point layer exists in the project, the following dialog will be displayed.



Create blank points layer or go back to the workflow panel to import point list in csv format. Please refer Import References for how to import point list file.



On the right side of the screen, you will see the Occupation and backsight localization workflow panel. In this panel you will set the following fields:

  • Occupation Point: Select by using the drop down in the dialog, or by picking the point graphically in the model pane as shown in the image below.
  • Instrument Height: You can enter this manually, or by turning on the GLS' ability to measure its own height using the special target supplied with your GLS.
  • Backsight Point: Select by using the drop down in the dialog, or by picking the point graphically in the model pane.

Also, you can create a new reference point by tapping the button to show the dialog below to specify coordinates as necessary.



Once you have entered the points you want to use, along with the instrument height, tap the Measure Target button and you will be taken to the Target Measurement screen to measure the backsight point. Further instructions to complete the observation can be found at the Target Measurement article.



Once you have measured the backsight point, tap the Localize Station button to run the localization process. After the process is complete, the Registration Quality Report will be viewable.



Tap the X button in the top-right of the report. Then, next operable options will be displayed on the Workflow panel.