STAR*NET V6 - Circe

Chapter 6 Running Adjustments
The STAR*NET adjustment produces a number of files. For example, the listing file
contains the complete results of the adjustment run. The points file contains the
coordinates of your adjusted points. The error file lists any errors or warnings generated
during the run. These files, other output files and a network plot can be viewed from
selections in the Output menu.
6.3 Data Check Only
Before you run an adjustment the first time, you may wish to simply check the input data
rather than run the adjustment. Choose Run>Data Check Only to run this routine. This
is not an adjustment! When you run Data Check Only, a modified version of the listing
file is generated, and you can plot the unadjusted network.
The Data Check Only feature performs two functions:
1. First, all input data is read into memory. If you have any syntax errors in your data
files, STAR*NET will issue error or warning messages in the error file which you
can review and take any action required. Your input data observations will be
summarized in the listing file.
2. Secondly, all observations (angles, distances, etc.) found in the input data are
checked for consistency with the approximate coordinates.
Whenever STAR*NET reads in data, approximate coordinates are computed for all
points using the observations found in your data. The program then calculates the
difference between each “entered” observation and its respective “inversed” observation
calculated from the approximate coordinates. Your listing file will contain a section
entitled “Differences from Observations” for each data type. Some observations will
show no differences since they may have been used to actually calculate the approximate
coordinates. But other observations not used to calculate coordinates may show some
differences. When observations in a network are consistent with each other, differences
shown in the listing should be quite small. The appearance of large difference values
likely indicates bad observations, or errors in preparing data.
This ability to check consistency of input observations to approximate coordinates is
particularly useful for finding “badly” fitting observations being added to a known
“good” network. Simply supply the coordinates from your previous good adjustment of
the network as approximate coordinates in your new data. (When approximate
coordinates are supplied, they won’t be computed from the observations.) Run the Data
Check Only routine and then check the listing for any of the new observations not fitting
the “good” approximate coordinates.
As indicated above, the Data Check Only routine only reads in data and does a simple
check of consistency between observations and approximate coordinates. For a more
rigorous method of finding blunders, see Blunder Detect in the next section.
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