Landsat started in 1972....it was an American initiative. Weather satellites had been operational since 1960 but no-one had thought about looking at terrain until the idea was put forward in the mid 60s as a direct result of fly by viewings of distant planets..... a case of "Hey guys, why don't we look at our own planet too?"
I guess companies and researchers paid money for pictures from the Landsat satellite dataset in the 70s, 80s and 90s. I recall buying a satellite image to help when hiking in Tierra del Fuego in 2001 due to the lack of decent topographical maps - it's all sensitive border country. Unfortunately its scale was such that a three day hike was equal to the width of the tip of my little finger, so not much use for hiking, but a very pretty picture of the south of Patagonia (both sides of the border).
The internet, with images, rather than just text got going in the early 90s.
So question - when did you personally get hold of a computer in your house, connect online and start looking at web pages with pictures? Painfully slow over a dial-up modem.... then domestic connections got faster. I recall the day that I had two web pages open simultaneously(!) on my home computer without the whole thing timing out and grinding to a halt.
The Sentinel 1* (radar imagery) satellite launched in 2014.
Sentinel 2 (day light imagery) launched in 2015.... both are a European initiative.... with every image made available for free (at poorer resolutions) or at a cost (for really good resolutions of specific areas).
Make something free and people will find all sorts of unexpected uses for them. Keep improving the resolution and more things become possible. (I recall reading a study by an Australian PhD student who was monitoring the effectiveness of the rabbit-proof fence they built across western Oz - the vegetation was clearly different just after the rainy season - with a clear north-south line.)
I started following GGP's progress and learning how to use the available online satellite imagery courtesy of folks like PaddyG, AM90 and Value_Seeker (and probably others whose names I have forgotten) in mid 2018 inspired by reading the GGP LSE board.
Since then I have discovered that relatively fresh satellite imagery has all sorts of handy uses courtesy of "good enough" resolution for Scottish hiking such as working out snow cover on ridges in spring; reaching normally inaccessible islands courtesy of dry summers and low water levels in lochs; and for large beaches where sands shift a lot working out the arrangements of spits and lagoons at low tide so you can plan a walk without getting caught out.
*Sentinel-1B was declared official dead on 3rd August 2022 - "bad soldering" was blamed for weakening a capacitor in a power supply, tsk tsk, always wipe your soldering iron tip properly - and not on your trouser leg. Sentinel-1B is the satellite that did radar for our latitude at HAV. The good news is that they are launching Sentinel-1C in 2023 - or maybe even sooner - in late 2022. The rocket used is part manufactured in Ukraine - so we can blame that pesky Putin for causing uncertainty about quite when. The intention is for 1C to fill in the blanks left by the sad demise of 1B.
Read more here:
https://spacenews.com/esa-ends-efforts- ... ntinel-1b/