Providing a New Approach to Optimize Combined Scale Factor Allocation Insurveying Projects

Nowadays, given the widespread use of global projection systems such as the UTM projection system in surveying projects relying on elliptic referents, finding a suitable composite scale factor for each project to implement construction projects using mapping equipment such as devices Total station is necessary. Unfortunately, today the method of calculating and assigning average composite scale factor in survying projects is not fully scientifically performed, and usually inappropriate composite scale factors are calculated and applied, causing unacceptable errors in the project. In this research, an executive project was investigated and a number of scaling factors were calculated for it. The results showed that the method that calculated the scale factor by considering the whole project scope in three dimensions yielded the most accurate case. Evaluation of the accuracy of work showed that the highest error was related to the average scale factor in a thousand meters length, 0.048 m to the east and west end of the project and 0.002 m to the center of the project. It was also found that if the permissible error of the mean scale factor is 5 mm, about 1266 m can be survey from the project center east and west with the same mean scale factor and if more than That range of surveying activity should be done, either more error must be accepted or another average scale factor calculated for the new range.