STAR*NET V6 - Circe
STAR*NET V6 - Circe
STAR*NET V6 - Circe
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Chapter 8 Analysis of Adjustment Output<br />
8.11 Adjusted Observations and Residuals (Optional)<br />
<strong>STAR*NET</strong> next lists all adjusted observations and their residuals. A residual is the<br />
difference between the observed value and the corresponding value computed from the<br />
adjusted coordinates. The sizes of the residuals are an indication of how well your<br />
observations have fit into the adjusted network. The observation standard errors you<br />
specified are also listed to show you how much weight each observation had in the<br />
adjustment. Although this section of the listing is optional, it is an important one that you<br />
normally will want included.<br />
Adjusted Observations and Residuals<br />
===================================<br />
Adjusted Angle Observations (DMS)<br />
At From To Adj Angle Residual StdErr StdRes<br />
1 701 2 123-40-27.22 -0-00-00.12 4.55 0.0<br />
2 1 3 217-11-36.03 -0-00-00.94 4.99 0.2<br />
3 2 4 113-53-19.28 0-00-21.27 5.18 4.1*<br />
Adjusted Distance Observations (FeetUS)<br />
From To Adj Dist Residual StdErr StdRes<br />
1 2 537.5551 0.0351 0.0211 1.7<br />
2 3 719.5360 0.0260 0.0273 1.2<br />
3 4 397.6922 0.0322 0.0202 1.5<br />
Adjusted Observations and Residuals<br />
You should examine the residuals carefully to see whether they appear reasonable.<br />
<strong>STAR*NET</strong> computes an additional value called the Standardized Residual (StdRes),<br />
which is equal to the residual divided by its standard error. This ratio takes into account<br />
the different types of observations (i.e. angles and distances) and the different units of<br />
standard error (i.e. seconds and feet) assigned to them, and and lets you easily make<br />
comparisons of the changes to all observations as “Standardized” residuals.<br />
You can also think of this value as the ratio between your observation’s actual fit in the<br />
adjustment (its residual), and your estimate of the strength (your input standard error). If<br />
the ratio is less than 1.0, it actually fit better than you had estimated. If it is larger than<br />
one, it didn’t fit as well. However, Standardized Residuals usually have a value greater<br />
than 3.0 before we can really say that there is a problem. Values greater than 3.0 are<br />
flagged with “*” to help you locate them quickly.<br />
The cause of any flagged values should be investigated. However, no observation should<br />
be deleted until a good reason is found for the problem. A large residual in a particular<br />
observation may be the result of a blunder in some other observation.<br />
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