Land Surveyor

### In Traverse Calculation which Rule is used mostly? Bowditch Rule or Transit Rule?

In Traverse Calculation which Rule is used mostly for corrections?

Bowditch Rule or Transit Rule?

I mostly prefer Bowditch Rule what you will prefer?

I have prepared an Excel spreadsheet for traverse calculations by both Bowditch Rule and Transit Rule.

I also attached the excel file with this discussion.

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#### Replies

• The transit rule was more or less the standard here in the US until PC's came into use and Least Squares was developed.  Even today with smaller traverses transit is superior to Least Squares.

Good Luck

Kevin

• Land Surveyor

Dear Mr. Samata,

That looks like a very useful Excel workbook! Thank you for the download.

COMPASS RULE (Bowditch)

The compass or bow ditch rule which was named after the distinguished American navigator Nathaniel Bowditch (1773-1838). His book The New American Practical Navigator (1802) is still carried on board commissioned U.S. Naval vessels.

The compass rule is based on the assumption that all lengths were measured with equal care and all angles taken with approximately the same precision. It is also assumed that the errors in measurement are accidental and that the total error on any side of the traverse is directly proportional to the total length of the traverse.

The compass rule may be stated as follows: the correction to be applied to the latitude or departure of any course is equal to the total closure of latitude or departure, multiplied by the ratio of the length of the course to the total length or perimeter of the traverse. These corrections are given by the following equations.

TRANSIT RULE

The method of adjusting a traverse by the transit rule similar to the method using the compass rule. The main difference is that with the transit rule the latitude and departure corrections depend on the length of the latitude and departure of the course respectively instead of both depending on the length of the course.

The transit rule fits better with the rules of the U.S. Public Lands System that relies heavily on cardinal directions. The Bowditch rule inherits its properties from navigation.

JAC

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