Volume 2021 Number 98
  • E-ISSN: 27887138


Ever since humans have felt the need to survey what was happening in the environment around them, a higher vantage point has been considered useful. Trees, hills and mountains served this purpose until humans were able to ‘fly’. Balloons, airplanes and later satellites offered observation platforms that enabled a more general and complete perception of the earth’s surface. The need for such a view was initially driven by military purposes, but other applications have also greatly exploited the possibilities.

Sustainable Development Goals:

You do not have access to article level metrics. Please click here to request access

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error