TPC can reduce random error inherent in survey measurements through a Least Squares adjustment. A Least Squares adjustment can be applied to something as simple as a resection and as complicated as a 3-dimensional network. The result is adjusted coordinates that are statistically more accurate than those derived from simple intersection and traverse adjustments. Learn more about Least Squares in the Least Squares Overview.
The Least Squares Network Adjustment tool is displayed when you choose Tools | Least Squares Network Adjustment from the main status bar, or from the Traverses Manager.
TPC's Least Squares Network Adjustment tool streamlines the process of creating and reviewing a least squares network. The dialog box's tabs are labeled in the logical step order for creating a least squares network.
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Step 1- Analyze -----> Step 2 - Solve -----> Step 3 - Report -----> Step 4 - Update
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In this step, TPC analyzes your survey data and builds a model that Least Squares can solve. TPC considers protected points, traverses, extra field ties, control points, side shots, and so on. You determine which traverses to consider and whether to do a 2-D or 3-D analysis and TPC does the rest.
Once TPC has built the network, you can edit it. You might want to fix certain points, exclude certain observations or edit precisions. Once you have the network the way you want it, you can solve and evaluate it.
For additional information on how to preform this step from the Least Squares Network Adjustment window in TPC see: Step 1 - Analyze
In this step you tell TPC to solve the network using Least Squares. TPC computes the adjusted coordinates along with all the statistics for coordinates and observations. Your survey is NOT affected during this step. TPC assumes you will want to evaluate the solution before you update your survey.
TPC reports the statistics associated with the network solution. This information allows you to evaluate the strength of the adjustments. If you find weak adjustments, you can edit the data and solve it again. You can repeat the Edit – Solve – Evaluate steps as many times as needed to improve your Least Squares solution.
For additional information on how to preform this step from the Least Squares Network Adjustment window in TPC see: Step 2 - Solve
Once TPC has computed a Least Squares solution, you can include information about the solution in a report.
For additional information on how to preform this step from the Least Squares Network Adjustment window in TPC see: Step 3 - Report
Once you are ready to accept the Least Squares solution into your survey, you just tell TPC to update the survey points. Your survey doesn’t care if the adjusted coordinates came from a Compass Rule adjustment or Least Squares. The adjusted coordinates are all treated the same. And of course you can always undo any adjustment at any time.
For additional information on how to preform this step from the Least Squares Network Adjustment window in TPC see: Step 4 - Adjust
Least Squares
Least Squares Overview
Least Squares Traverse Adjustment
Least Squares Network Adjustment
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