PRACTICAL 1: TOPOGRAPHIC CONTOURS, STRUCTURAL CONTOURS AND GEOLOGICAL MAPS.
		Problem: Can we construct - on a 2D map - the trace of the intersection between the geological surface and the topographic surface, this trace is called a form line.			Solution: we superimposed both the structural map and the topographic map. Since the elevation of each contour is known it is straitforward to find the intersection between the two sets of contours. On the map below these intersections are marked with red dots. The line connecting theses dots represents the intersection between the geological surface and the topography surface. This line is also called a "form line".