WinTri (Win = Windows, and Tri = Trilateration) is a computer program that accepts trilateration survey data and calculates the corresponding coordinates of survey points.  WinTri contains extensive error checking of the input data and provides detailed  messages when errors are found.  For further help in locating errors, the program offers the possibility of printing out the results of intermediate calculations.

WinTri was initially developed for the Geotechnical Branch of the St. Louis District of the U. S. Army Corps of Engineers and has been tailored to fit the formats of the Geotechnical Branch's input survey-data and output (to a database program).  Other prospective users of the program may either (1) change the format of their survey data to match that used by WinTri, or (2) modify the source code of WinTri to accept their survey data in its original format and to produce output in a newly specified format.  WinTri is written in Visual Basic and was designed to allow the source code that handles input and output to be modified relatively easily.  Because program development was paid for by the Corps, the executable and the source code are available at no charge.

A self-extracting compressed file containing the program executable is available to  download.  The downloaded file may be expanded by clicking on the file name in your Windows file manager.

WinTri may then be installed by running the set-up program, "setup.exe" and may be run by selecting "WinTri" from the Start/Programs menu on the Windows Desktop.  Complete details of the required format of input data are given in the Help screens.

Questions about the program or requests for obtaining the source code should be directed to the author at

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Edited by M. P. Rossow