Historical Development of Geospatial Technologies in 20-21 Century:
Geospatial Technologies would not be possible without the development of computer industry since 1970s, but many principles and functions in these tools were used and developed more than 3,000 years. For example, geometric measurements and algebraic computations were known in Ancient world of Egypt and Asia. Earth measurements were conducted by Eratosthenes in 150s BCE, revolutionary geographic principles of navigation were in use in 18th and 19th centuries during great geographic discoveries. But only in 20 century computer technology allowed geospatial technologies to become what they are today.
Additional References:
Berry, J. 2007. A Multifaceted GIS Community, GEOWorld, January, 20 (1),16
Geography, Computer (hardware, software), English Language (read, write), Mathematics (algebra, statistics, arithmetic, calculus, etc.), Use of Training and Educational materials.