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Post by Hutch on Sept 17, 2005 8:07:34 GMT
Google EarthI don’t know if any of you have explored this free online resource yet but my job pointed me in its direction and it is quite magnificent. Simply, it contains satellite imagery of the whole Earth some of it quite detailed and I would highly recommend it. The resource is Google Earth and it’s causing quite a stir in the mapping world. I have a 2MB broadband connection on Windows XP so it may not work for all. Most of the USA is extremely high resolution, as one would expect for a home audience. We used to live there until recently and in the image of our old house I can see my wife’s car in the drive way! Only parts of the UK are high resolution but the parts that are include London and the surrounding LUL system. This picture by way of example shows an oblique aerial shot of the Barking flyovers northwest of the station. Simply type in your destination (place and country) into the search box and hold on as you zoom out fly around the Earth and then auger in. Warning:- it can induce vertigo in the more sensitive of viewer  Explore and enjoy.
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Post by Deleted on Sept 17, 2005 11:32:09 GMT
Alas, the coverage is VERY patchy!
Central London is covered in excellent detail, but get as far out as Finchley and it's all blobs. Much the same for other European countries and Australia: detail in the major cities, but elsewhere there's not really anything you could not get from a good map.
I'm a geographer by training, and I suspect that the really detailed material comes from mapping photos taken from planes rather than satellites, with the fuzzy stuff coming from satellites.
I don't believe the claims that there are satellites that can read a car number plate. Quite apart from the fact that number plates do not face upwards, the distortions arising from the atmosphere would make it totally impossible to resolve that detail from a satellite.
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Post by Hutch on Sept 17, 2005 18:55:55 GMT
I agree its patchy and not what you would get everywhere from a really good map (and I love maps) but how many maps and what global coverage do you have? How many maps do you have at a scale to see cars, or trains, or planes?
I do not think they are aerial photograph montages. Check the parallax on the buildings across the scene.
The scenes are too big and they have that characteristic rhombohedral shape of a polar orbit satellite scan. LandSat has a 15m pixel size (I think these comprise the majority of the material). ASTER can get you down to 5m and the European SPOT gets you down to 2m. There are other commercial sats with resolution in the sub-metre range if you are prepared to pay – the amazing thing about this resource is that it's available for free online!
I was just looking at the layout west of Turnham Green and can see that there are the outlines of two disused underpasses only one of which was used by the Midland coal trains post 1912. The space between the tracks left by the lifted goods loop is very visible on the image east of the station.
There is so much to see at the resolution available. Yes, my house in south Oxfordshire is lost in a low resolution blob, likewise the house I was raised in up north but those areas with the detail more than make up for it. Have a squiz at Singapore International Airport ...
or the Gibraltar border crossing – it’ll warm the cockles of your geographic heart! ;D
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Post by Tomcakes on Sept 17, 2005 20:26:44 GMT
Multimap gives good quality arial photographs, I agree Google Earth is good but to see a brown splodge for my street isn't that awe-inspiring.
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Post by Deleted on Sept 17, 2005 20:32:37 GMT
Multimap gives good quality arial photographs, I agree Google Earth is good but to see a brown splodge for my street isn't that awe-inspiring. Isn't a brown splodge an appropiate image of Doncaster then? *Ducks down to avoid heavy flying objects* |
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Post by Tomcakes on Sept 18, 2005 9:57:58 GMT
I thought you lived in Upminster  ? |
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Post by Deleted on Sept 18, 2005 14:35:13 GMT
I thought you lived in Upminster ? Oooh! Handbags at dawn! ;D |
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Post by ikar on Sept 18, 2005 15:50:44 GMT
My home town is a green splodge in stage 4 zoom  But you can see it good from stage 5-6 zoom |
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Post by Deleted on Sept 18, 2005 20:29:25 GMT
You can see my house clearly in Google Earth, even able to tell that, 1/ I was re-building my garden fence, 2/ I was at work, as my car can be seen in the car park at work (Jeffs Coaches Greens Norton at that time) so that view must have been taken in 2003.
What other trivia can you spot for your area?
/sad git
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Post by Deleted on Sept 18, 2005 20:30:58 GMT
Multimap gives good quality arial photographs, I agree Google Earth is good but to see a brown splodge for my street isn't that awe-inspiring. The last time I went to Donny, it was indeed a brown splodge! |
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Post by Dmitri on Sept 19, 2005 7:45:45 GMT
I don't believe the claims that there are satellites that can read a car number plate. Quite apart from the fact that number plates do not face upwards, the distortions arising from the atmosphere would make it totally impossible to resolve that detail from a satellite. You're quire right - I've seen calculations showing that you would need a telescope with a lens several metres (if not over 10 metres) in diameter, and air distortions will certainly make the whole undertaking hopeless. |
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