One of the important tasks of geodesy is to investigate the deformations that occur in the earth's crust and structures. Control measurements are made especially in engineering structures both during and after construction. The measurements are evaluated for investigating whether there is a threat or not. Different methods of analysis are used in the evaluation of the measurements. In this study, Relative Confidence Ellipses Method, which is one of the static evaluation methods used in the determination of deformations in the horizontal direction, is theoretically examined, using direction observations and ranging data measured in Ermenek Dam for two periods and deformation measurements were conducted by analytical and graphical methods. Geodetic network consists of 13 reference points... and 10 object points which were located on the crest. Evaluation was made separately both for direction observations and for direction observation + ranging data. With 95% statistical confidence, any deformation was not observed on 6, 7, 8, 9, 12, 13 reference points and 104, 501 object points in the evaluation according to direction observations and on 6, 12, 13 reference points in the evaluation according to direction observation + ranging data At the points subjected to deformation, deformations between 1.91 mm- 7.35 mm based on only direction observation and deformations between 1.46 mm- 6.60 mm based on both direction observations and ranging data were determined.