Author Topic: GooogleEarth / satellite Question  (Read 1185 times)

0 Members and 1 Guest are viewing this topic.

Offline Steve F

  • I have "some-timer's disease" because I'm an
  • Old Timer
  • ******
  • Posts: 2,928
  • "To Ride Is The Reason, The Destination The Excuse
GooogleEarth / satellite Question
« on: April 14, 2009, 07:23:23 PM »
Anyone here know anything about the satellite photos taken and how certain things appear as they do?  I have a particular question about an image that I found, and it really puzzles me.  I was snooping around Chicago O'Hare airport, and spotted a plane that had just taken off, going south-east.  The plane apears twice in the image, and separated by maybe 200 feet.  Weird.  Why is that?
Here are the coordinates, (copy/paste into GoogleEarth) and zoom in really close to see the cool details:
41 57 16.83n 87 50 38.29w
« Last Edit: April 14, 2009, 07:24:54 PM by Steve F »

Offline myhondas

  • Not really such a
  • Expert
  • ****
  • Posts: 1,439
Re: GooogleEarth / satellite Question
« Reply #1 on: April 14, 2009, 07:46:30 PM »
When you see the high detail photos, they are not taken from a satellite but from an airplane. These are multiple shots that are composite of many photos. In fact, they are usually overlapped by 60 to 80% so as the photos are being taken, something as fast as another airplane can exceed the overlap and show up on multiple photos. Cars and people are not moving fast enough to do this but an airplane can during some aspects of flight in relationship to the plane that is taking the photos.
1974 CB 750 K4 SHOWROOM
1974 CB 750 K4 IN PART-OUT PROCESS (my original bike)
1965 C100 CUB 50 (PIT BIKE)
1996 VF 750 CD daily rider
1983 VF 1100 V65 Magna in restoration process
SOHC# 5105 11228

Offline kghost

  • Really Old Timer ...
  • *******
  • Posts: 6,853
  • www.facebook.com/RetroMecanicaAustralia
Re: GooogleEarth / satellite Question
« Reply #2 on: April 14, 2009, 07:51:17 PM »
Yup.

Its a mexicana bird too...prolly coming my way.

Oh well my house doesn't show.....
Stranger in a strange land

Offline 333

  • Time for change
  • Really Old Timer ...
  • *******
  • Posts: 7,558
  • Mail List Member #162 - Call me Stan
Re: GooogleEarth / satellite Question
« Reply #3 on: April 14, 2009, 07:59:59 PM »
My guess is that some sort of composite/panoramic photography is used so that in the time it took to pan for the next shot, that plane was in that next shot.

As for it being satellite or not, I believe it is.  Google specifically calls it that.  As opposed to aerial.  That and the copyright mentions the U.S. Geological Survey, which I know uses satellite imagery.

What I just noticed was how old the image is of my house.  A tree next door was cut down 2 years ago, and it is in the picture tonight.  As well as all the leaves on the rest of the trees.  And while I didn't specifically didn't look at the trees today, I'm pretty sure the leaves haven't popped out yet
Go metric, every inch of the way!

CB350F0  "Scrouching Tiger"
CT70K0    "Sneezing Poodle"

www.alexandriaseaport.org

Offline myhondas

  • Not really such a
  • Expert
  • ****
  • Posts: 1,439
Re: GooogleEarth / satellite Question
« Reply #4 on: April 14, 2009, 08:24:05 PM »
I suppose I should have posted my qualifications to answer the question as I did.  I fly a aerial survey plane that takes these kinds of photos. Google Earth uses a composite of both satellite and aircraft photos. You can tell the difference by the detail available as you zoom in. We take photos for the usgs and in fact, they certify our equipment. We take photos for everyone from the us government, states, counties, cities, and contractors and developers. Even the composites can be put together from multiple flights. That can be seen via cloud shadows and building/structure shadows changing within a line of pics. As you zoom out, you will see a patch work of different shades that look a lot like a quilt. The air photos are usually a little darker since they have much more detail than the satellite. Most often, except when they are on the ground or just taking off over the runway, aircraft are removed from the photos since they obstruct the photo of the ground. I would have to say that this aircraft somehow escaped the eraser tool. You can sometimes find a shadow of an aircraft that has just taken off and has left the airport environment, but there is no airplane. I think I saw that just east of atlanta, ga. Shadow of plane on building roof, but no plane to be seen.
« Last Edit: April 14, 2009, 10:24:19 PM by myhondas »
1974 CB 750 K4 SHOWROOM
1974 CB 750 K4 IN PART-OUT PROCESS (my original bike)
1965 C100 CUB 50 (PIT BIKE)
1996 VF 750 CD daily rider
1983 VF 1100 V65 Magna in restoration process
SOHC# 5105 11228