In the present paper was developed and investigated based on numerical simulation method of calculation errors in determining the coordinates of points of thermal images. These images can be used for remote investigation of the technical condition of some facilities of electric networks, especially overhead power lines. The article describes in detail the analytical method developed by the error estimates of coordinates of points given thermal images. The main sources of errors in determining the coordinates of points of thermal images are errors in determining the coordinates and angular orientation of objects - carriers of diagnostic equipment. The developed method makes it possible based on the specified number of errors of measurement characteristics of the primary parameters to calculate the values ​​of mean square errors in determining the coordinates of the given point thermal images. A comparison of errors obtained by an analytical method with the results of error estimates obtained by the method of statistical modeling, which confirmed the correctness of the calculated ratios.