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GSD is an abbreviation for ground sample distance. In photography, it refers to the distance between the centers of pixels next to each other. The smaller this value is, the better image we are able to obtain, the representation of reality in the image is better; smaller details are visible.

It’s the same if we look at the world from orbit – we’re able to see constantly occurring changes on a larger scale – both in terms of terrain, but also over a longer period of time. The balcony from which we take a picture may be obscured by another building, while the view from orbit would never be so obscured – having satellite image processing software, we are able to easily compare two pictures from two different time periods.

The first ever aerial photograph was taken by Gaspard-Félix Tournachon in 1858 from a balloon. He photographed the town of Bievre in France using the wet plate collodion process photography.

Thirty years later, in 1888, Arthur Batut using a camera hooked up to a kite, took aerial photos of the town of Labruguiere. Interestingly, the photos were taken only after the kite had reached a certain assumed altitude; an altimeter was attached to the system.

In today’s article, we will answer some basic questions that may be on the minds of aspiring space enthusiasts.

Water covers more than 70% of our planet’s surface, which has a direct impact on our daily lives. Acquiring up-to-date, high-resolution information makes it possible to predict the weather, but it also makes it possible to observe climate change, map the ocean floor, observe coral reefs, or measure tidal heights.

Before discussing the tests themselves, let’s go back in time a bit. The system (telescope, satellite, subsystem) was designed in CAD software – but unfortunately, the reality is often (almost always) different from the theory – some calculations may have been made incorrectly, some details may have been overlooked, and various problems or errors may have occurred during the integration itself.