Home > Survey Mode > Reductions > Control Network > Introduction

Control Network Fieldbook

Display the Control Network fieldbook.

This function allows you to adjust provisionally fixed points that have redundant observations, by means of a least squares solution.

A rough fix for the free points should be calculated prior to using this routine, which is usually done under Survey Calculations. The data for the calculation must be provided in the form of a field book.

Requirements

Any control network survey requires at least two fixed points from which to adjust the network. At least one free point (provisionally fixed) must be present in order for the solution to calculate.

The free points must have provisional coordinates. These can be obtained using the various survey calculation routines such as Resection, Intersection and Trilateration.

Below is an example of a control network.

As can be seen from the diagram, it is not necessary to set up at all stations. There must, however, be redundant observations in the network like, for example, the observations to FREE1 from FIXED1, FREE2 and FREE3.

The network also conforms to our requirements, in that there are four fixed points (TRIG1, TRIG2, FIXED1 and FIXED2), and five free or provisionally fixed points (FREE1 to FREE5).

Procedure

1. The Control Network Fieldbook displays.

2. Select one of the Fieldbook menu options:

• • New

  • Load

  • Save

  • List

3. Select the Reduce option to reduce the fieldbook data.

4. Select Assistant to interactively load the data from the Observations and Figures database.