Geological map is a graphical representation of geological featuresand related interpretations on a horizontal plane. A geological section isidentical in nature to a map except that data are recorded and interpreted on avertical rather than a horizontal surface. Maps and sections are essentialtools in visualizing spatial, three dimensional, geological relationships. Theyallow theories and controls to be applied and lead to predictions (orhypothesize) being made on the location, size, shape and orientation of bodies.Geological maps are the essential tools to aid in developing 3-dimentionalconcepts about geology and relation of the structures to endogenic and exogenicprocesses (Marjoribanks, 2010).
John Proffett (Proffett, 2004), a widelyregarded and one of the most skilled geological mappers commented thatgeological mapping is a method of recording and organizing observations, muchof its power in targeting lies in providing conceptual insight of value.Making, or otherwise acquiring, a geological map is invariably the first stepin any geological investigation programme and it remains an important controldocument for all subsequent stages to envisage the history of evolutionincluding geochemistry, geophysics, geostatistics.There areseveral types of geological maps. With large-scale geological maps, thegeologist generally aims to perform and outline every significant rock andstructure of the outcrop in the mapped area. For that reason these are oftencalled “fact” maps, although “observation” or simply “outcrop” map is a muchbetter term.
In a small-scale map, visiting every outcrop would be impossible;generally (in context of Earth) only selections of outcrops are examined in thefield and interpolations have to be made between the observation points. Suchinterpolations may be made by simple projection of data or by making use offeatures seen in remote sensed images of the area, such as satellite images.Small-scale maps thus generally have a much larger interpretational elementthan large-scale maps.