A method, tool, and device for determining the coordinates or a plurality of points on a substantially plane surface by means of an accelerometer and a camera. The coordinates of each point are computed by determining a perpendicular projection of the camera onto the surface, identifying each point, measuring an inclination (the angle between the line of sight of the camera and gravity) using the accelerometer, and determining an azimuth (the angle of the line of sight of the camera around gravity).