West of Heathrow - one plane, two shadows discussion

manxIX · 06-07-2009, 09:25 PM

This is a discussion thread for the following file:

West of Heathrow - one plane, two shadows

The same location as http://www.gearthhacks.com/dlfile32098/Airbus-A340-from-Qatar-Airways.htm but here you can see that there is one original plane with two shadows. For the second shadow there is no photographed original, it seems to be vanished. Very strange...

manxIX · 06-07-2009, 09:34 PM

Hi
Surely you mean one aircraft THREE shadows.

The correct shadow, if you follow the direction of the thrown shadows, is on the squareish reservoir almost due north of the aircraft.

That leaves the problem(s) of the other two shadows to the west. Higher flying aircraft perhaps?

Why 3 aircraft throwing shadows in almost the same place, at the same time and over the busiest airport in the world?

Well spotted and very hard to explain.

geronimo · 06-09-2009, 09:14 AM

Thanx for your correction. You are right, there are THREE shadows. Very mysterious...

SpiderX22 · 06-10-2009, 12:59 AM

File edited so that "two shadows" is now "three shadows" to avoid further confusion.

Fritriac · 06-17-2009, 07:29 PM

Looks like shadow #3 is the original one (just look at the shadow direction of the power poles in the west of the plane).

So why? Not all pics from Google Earth are satellite photos, the most of them (with much better quality) are aerial photos from planes. So when each of these photos covers -let's take a number- 600m x 600m of the ground, the plane takes one photo every ~500m. Then the next series, 500m away from the first flight path etc.

Later the single photos are stacked together with some graphics software and - voilá.

But: To avoid gaps in the resulting picture, the photos have to overlap!

Here a scenario:

Photo plane on its first flight path
Photo 1-1: Plane and shadow are both on the picture
Photo 1-2: Plane and shadow on the picture, but plane in the overlap-area
Photo 1-3: Shadow is still on the pic, plane is outside

Photo plane on its next path, 500m to the south
Photo 2-1: No plane, doesn't affect 1-1
Photo 2-2: No plane, overlaps plane on 1-2
Photo 2-3: No plane, overlaps again

My scenario, let me show you it

:

Link to a bigger version

I know a guy who does exactly this (not actual taking the aerial photos but processing photos this way). The software they use is really sophisticated: You don't need to stack photos per hand anymore, different saturations and/ore hues will be automatically corrected, soft transitions ... yadda, yadda, yadda.

Maybe this will also clarify some other "map quirks" ...

Appletom · 06-17-2009, 08:21 PM

This has to be the best explanation - with photographic evidence [complete with with circles and arrows and a paragraph on the back] for missing planes (or, conversely, for missing shadows) I've seen yet.

Thank you Fritriac!!!

I'm bookmarking this thread for reference for the next time someone asks "Where's the shadow?"

06-07-2009, 09:25 PM	#1
manxIX Junior Member Join Date: Oct 2008 Location: Isle of Man, Great Britain (not in the UK or EU!) Posts: 12	West of Heathrow - one plane, two shadows discussion This is a discussion thread for the following file: West of Heathrow - one plane, two shadows The same location as http://www.gearthhacks.com/dlfile32098/Airbus-A340-from-Qatar-Airways.htm but here you can see that there is one original plane with two shadows. For the second shadow there is no photographed original, it seems to be vanished. Very strange...

06-10-2009, 12:59 AM	#4
SpiderX22 ṨῤἵḋểṙẊƻƻ Join Date: Feb 2006 Location: Massachusetts Posts: 3,603	File edited so that "two shadows" is now "three shadows" to avoid further confusion. __________________ 1 + 1 = 11

06-17-2009, 07:29 PM	#5
Fritriac Member Join Date: Oct 2007 Location: 50°35'2.06"N, 8°31'51.24"E Posts: 37	An explanation - maybe... Looks like shadow #3 is the original one (just look at the shadow direction of the power poles in the west of the plane). So why? Not all pics from Google Earth are satellite photos, the most of them (with much better quality) are aerial photos from planes. So when each of these photos covers -let's take a number- 600m x 600m of the ground, the plane takes one photo every ~500m. Then the next series, 500m away from the first flight path etc. Later the single photos are stacked together with some graphics software and - voilá. But: To avoid gaps in the resulting picture, the photos have to overlap! Here a scenario: Photo plane on its first flight path Photo 1-1: Plane and shadow are both on the picture Photo 1-2: Plane and shadow on the picture, but plane in the overlap-area Photo 1-3: Shadow is still on the pic, plane is outside Photo plane on its next path, 500m to the south Photo 2-1: No plane, doesn't affect 1-1 Photo 2-2: No plane, overlaps plane on 1-2 Photo 2-3: No plane, overlaps again My scenario, let me show you it : Link to a bigger version I know a guy who does exactly this (not actual taking the aerial photos but processing photos this way). The software they use is really sophisticated: You don't need to stack photos per hand anymore, different saturations and/ore hues will be automatically corrected, soft transitions ... yadda, yadda, yadda. Maybe this will also clarify some other "map quirks" ... __________________ To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts. ... but never eat the yellow snow! (Inuit wisdom) Last edited by Fritriac; 06-18-2009 at 12:01 AM.

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06-07-2009, 09:34 PM	#2
manxIX Junior Member Join Date: Oct 2008 Location: Isle of Man, Great Britain (not in the UK or EU!) Posts: 12	Hi Surely you mean one aircraft THREE shadows. The correct shadow, if you follow the direction of the thrown shadows, is on the squareish reservoir almost due north of the aircraft. That leaves the problem(s) of the other two shadows to the west. Higher flying aircraft perhaps? Why 3 aircraft throwing shadows in almost the same place, at the same time and over the busiest airport in the world? Well spotted and very hard to explain.

06-09-2009, 09:14 AM	#3
geronimo Junior Member Join Date: Aug 2005 Posts: 10	Thanx for your correction. You are right, there are THREE shadows. Very mysterious...

06-17-2009, 08:21 PM	#6
Appletom Moderator Emeritus Join Date: Jul 2005 Location: El Paso, Texas Posts: 1,051	This has to be the best explanation - with photographic evidence [complete with with circles and arrows and a paragraph on the back] for missing planes (or, conversely, for missing shadows) I've seen yet. Thank you Fritriac!!! I'm bookmarking this thread for reference for the next time someone asks "Where's the shadow?"