Declination Statistics

Compass can adjust survey data in a variety of ways. For example, it can adjust surveys based on book-declination, calculated declination and it can also apply UTM convergence to surveys. Each of these adjustments can be set on a survey-by-survey basis, making it difficult to understand what is going in a large cave.

To help clarify and simplify what is happening in a cave project, Compass can display statistics on how these adjustments are applied to each individual survey. Here is a sample report:

Declinations/Convergence Adjustments By Surveys:

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                                Dec   Book    Calc    Work  Converge        Combined

Index      Dat File   Survey   Status    Dec     Dec     Dec    Status    Conv  Adjust

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0      ENTRANCE.DAT  Precisn     Book   0.00    0.00    0.00     Local   -0.26    0.26

1      ENTRANCE.DAT       AB     Book   9.96    0.00    9.96     Local   -0.26   10.22

2      ENTRANCE.DAT       AA     Book   9.85    0.00    9.85     Local   -0.26   10.11

3      ENTRANCE.DAT      AAA     Book   9.85    0.00    9.85     Local   -0.26   10.11

4      ENTRANCE.DAT        B     Book   9.96    0.00    9.96     Local   -0.26   10.22

5      ENTRANCE.DAT        A     Book   9.96    0.00    9.96     Local   -0.26   10.22

6      ENTRANCE.DAT       BF     Book   9.96    0.00    9.96     Local   -0.26   10.22

7      ENTRANCE.DAT       AC     Book   9.96    0.00    9.96     Local   -0.26   10.22

8      ENTRANCE.DAT       AD     Book   9.96    0.00    9.96     Local   -0.26   10.22

9      ENTRANCE.DAT       AE     Book   9.96    0.00    9.96     Local   -0.26   10.22

10     ENTRANCE.DAT       AG     Book   9.85    0.00    9.85     Local   -0.26   10.11

Here is a description of each field:

Dat File. This is the file where the surveys are found

Survey. This is the survey to which the adjustments are applied.

Dec Status. This field indicates the source of the declination adjustment. There are four options:

Ignore - This indicates that declination is ignored and is neither read from the book or calculated.

Book - This indicates that the declination value is taken from the survey book as entered into the computer.

Calc. Error - This indicates that the declination couldn't be calculated because of an invalid date, invalid location or a mathematical error.

Calculated - This indicates that the declination was calculated from the cave location and survey date.

Book Dec. This is the declination as entered in the survey book and entered into the computer.

Calc. Dec. This is the declination calculated from the cave location and survey date.

Work Dec. This is the actual declination that is applied to the survey. It can be either the book or the calculated declination.

Converge Status. This item give information about where Compass got the UTM convergence data.

Disabled. Indicates that convergence is disabled and no convergence was used.

No Data. Indicates that no convergence data was available.

Local. Indicates that Compass got the convergence data from the local survey data.

Project. Indicates that Compass got the convergence data from the project.

Unknown. Indicates and data file or software error.

Conv. This is the actual convergence value that Compass used.

Combined Adjustment. This is the total adjustment combining declination and convergence.