Surveying methods. 16th-century coloured woodcut showing the methods used by surveyors. Four men on the tower at left are using surveying equipment to measure the position of the stars and to take sightings of other landmarks in the surrounding area. Trigonometric analysis of the angles allows calculations of the distances and heights of the landmarks, allowing accurate maps to be drawn. This artwork is from 'Methodus Geometrica' (Nuremberg, 1598) by German cartographer Paul Pfinzing (1554-1599).