Brief History of Maps and Cartography (Modern Maps part 4)

MODERN MAPS
Maps became increasingly accurate and factual during the 17th, 18th and 19th centuries with the
application of scientific methods. Many countries undertook national mapping programs. Nonetheless ,much of the world was poorly known until the widespread use of aerial photography following World War II.

Modern Cartography
Finally, in the XIX, large Cartography Institutes were established and started to produce maps using more and more advanced systems. Modern technology widened the development of cartography , especially after World War II; thanks to aerial surveys that allowed accurate representations of the environment and with the birth of  photogrammetry, cartographical techniques  evolved enormously. The development of electronic calculators, the electronic measuring of distances through laser beams and the use of computer for the drawings together with more and more sophisticate software, led to a very rapid evolution in cartography.

Today’s most widely used system for the production of topographic maps is the aerial photogrammetric survey.

(photo made by Italian air force 1957)

To produce them an airplane has to fly in a straight line, at a constant altitude and speed and within a specified interval of time: it has to take a series of pictures of a given site  thus acquiring spatial data from different angles.

Satellite Charts
A true revolution has been made by ERTS (Earth Resource Technology Satellites),

 equipped with remote sensing instruments able to detect portions of the electromagnetic spectre that are invisible to human eyes. Information is transmitted to special stations where, through very sophisticate programmes, it is decoded an transformed into readable images. In this way data for high precision map making is acquired which includes places that are practically inaccessible. As a rule this equipment utilizes the infrared band wave because it can detected energy given off by different kind of materials on the surface such as rocks, soil, vegetation, water sites, buildings, infrastructures and then translates it into pictures or images necessary for the drawing up of thematic maps.  A great numbers of satellites fly above our heads following regular orbits that, on a daily basis, survey portions of land of varying sizes.