7 ms·

If you (like me) wondered why go back decades to what is pressumably lower quality imagery than what is available today, here is the spoiler: > They (cold war

If you (like me) wondered why go back decades to what is pressumably lower quality imagery than what is available today, here is the spoiler: > They (cold war era) “preserve a high-resolution, stereo perspective on a landscape that has been severely impacted by modern-day land-use change”

morkalork 3y ago
How did they get the stereo perspective, did they use a delay between photos from the same satellite so there was enough time for it to travel?
- sigmar 3y ago
  >The first CORONA satellites had a single camera, but a two-camera system was quickly implemented.[40] The front camera was tilted 15° aft, and the rear camera tilted 15° forward, so that a stereoscopic image could be obtained https://en.wikipedia.org/wiki/CORONA_(satellite)#Cameras https://en.wikipedia.org/wiki/CORONA_(satellite)#Cameras
  - _whiteCaps_ 3y ago
    And then you can view them with something like this: https://en.wikipedia.org/wiki/Stereoscope https://en.wikipedia.org/wiki/Stereoscope
- ska 3y ago
  There are different ways to do it, that's one of them. A lot of the techniques were first used with airplanes, then later with satellites. Lots of overlap because planes allowed for easier localization and better resolution, especially earlier on in remote sensing.
  - 13of40 3y ago
    I've done this from a plane before and got some very epic 3D images. I think Mt. Rainier at sunset was one of the best. So yeah, the easy way if your camera is on a moving platform, is take a shot, count three aligators, then take another shot.
lapetitejort 3y ago
Not only that, but > In addition, many of the likely Roman forts we have documented in this study have already been destroyed by recent urban or agricultural development, and countless others are under extreme threat.
deleted 3y ago
[deleted]
kristopolous 3y ago
How does this happen? Do you just see a bunch of ruins on your land and think "well if it was important people would know about it! Let's toss all this stuff in dumpster!"? I can't imagine how many things went down like that. Large Dinosaur repositories and people trying to plant some vegetables were like "geez another bunch of bones. Alright, into the fire"
- timeon 3y ago
  There were Roman excavations in area of castle in my city. They were replaced by underground garages.
- kortilla 3y ago
  Yes. Altruism does not scale. It is very likely they thought, “oh, this is some old looking shit but doesn’t look that important. Better clean it up quickly before the preservationists come in and bankrupt this project.”
- calvinmorrison 3y ago
  Certain groups of islamofascists intentionally destroyed known artifacts, ruins and even excavated and preseved sites like Palmyra during earlier stages of the Syrian Civil War. Also in areas that are in war time conflicts, or in poverty, preserving may not be a top priority. For example Gaza is the site of many historic cities dating thousands of years old.
  - deleted 3y ago
    [deleted]
- newsclues 3y ago
  Lots of people are highly motivated by the need to eat and don’t have the luxury of caring about history.
- Swizec 3y ago
  In most of Europe (and probably elsewhere), you can’t throw a rock without hitting some sort of historically significant thing. We used to smoke weed on the local Roman wall. It was also a popular destination for rock climbers to practice. The wall has been there for 2000 years. It’s fine.
fritzo 3y ago
I find stereo pair aerial imagery hugely helpful in understanding terrain. While Google Earth is great to get a gross overview, our eyes are much better at inferring sub-meter detail from pairs of stereo photos, e.g. from a single airplane taken a few seconds apart. What are some good sources of public aerial stereo imagery? The only source I've found is NOAA https://www.noaa.gov/topic-tags/aerial-imagery https://www.noaa.gov/topic-tags/aerial-imagery
- jakecopp 3y ago
  I wonder if it means photogrammetry can be used (eg. OpenDroneMap) to construct a 3D model of the landscape/buildings...

morkalork 3y ago

How did they get the stereo perspective, did they use a delay between photos from the same satellite so there was enough time for it to travel?

sigmar 3y ago
>The first CORONA satellites had a single camera, but a two-camera system was quickly implemented.[40] The front camera was tilted 15° aft, and the rear camera tilted 15° forward, so that a stereoscopic image could be obtained https://en.wikipedia.org/wiki/CORONA_(satellite)#Cameras https://en.wikipedia.org/wiki/CORONA_(satellite)#Cameras
- _whiteCaps_ 3y ago
  And then you can view them with something like this: https://en.wikipedia.org/wiki/Stereoscope https://en.wikipedia.org/wiki/Stereoscope
ska 3y ago
There are different ways to do it, that's one of them. A lot of the techniques were first used with airplanes, then later with satellites. Lots of overlap because planes allowed for easier localization and better resolution, especially earlier on in remote sensing.
- 13of40 3y ago
  I've done this from a plane before and got some very epic 3D images. I think Mt. Rainier at sunset was one of the best. So yeah, the easy way if your camera is on a moving platform, is take a shot, count three aligators, then take another shot.

lapetitejort 3y ago

Not only that, but > In addition, many of the likely Roman forts we have documented in this study have already been destroyed by recent urban or agricultural development, and countless others are under extreme threat.

deleted 3y ago

[deleted]

kristopolous 3y ago

How does this happen? Do you just see a bunch of ruins on your land and think "well if it was important people would know about it! Let's toss all this stuff in dumpster!"? I can't imagine how many things went down like that. Large Dinosaur repositories and people trying to plant some vegetables were like "geez another bunch of bones. Alright, into the fire"

timeon 3y ago
There were Roman excavations in area of castle in my city. They were replaced by underground garages.
kortilla 3y ago
Yes. Altruism does not scale. It is very likely they thought, “oh, this is some old looking shit but doesn’t look that important. Better clean it up quickly before the preservationists come in and bankrupt this project.”
calvinmorrison 3y ago
Certain groups of islamofascists intentionally destroyed known artifacts, ruins and even excavated and preseved sites like Palmyra during earlier stages of the Syrian Civil War. Also in areas that are in war time conflicts, or in poverty, preserving may not be a top priority. For example Gaza is the site of many historic cities dating thousands of years old.
- deleted 3y ago
  [deleted]
newsclues 3y ago
Lots of people are highly motivated by the need to eat and don’t have the luxury of caring about history.
Swizec 3y ago
In most of Europe (and probably elsewhere), you can’t throw a rock without hitting some sort of historically significant thing. We used to smoke weed on the local Roman wall. It was also a popular destination for rock climbers to practice. The wall has been there for 2000 years. It’s fine.

fritzo 3y ago

I find stereo pair aerial imagery hugely helpful in understanding terrain. While Google Earth is great to get a gross overview, our eyes are much better at inferring sub-meter detail from pairs of stereo photos, e.g. from a single airplane taken a few seconds apart. What are some good sources of public aerial stereo imagery? The only source I've found is NOAA https://www.noaa.gov/topic-tags/aerial-imagery https://www.noaa.gov/topic-tags/aerial-imagery

jakecopp 3y ago
I wonder if it means photogrammetry can be used (eg. OpenDroneMap) to construct a 3D model of the landscape/buildings...