Wednesday, 20 August 2008

What all the fuss is about.

You can get google earth by clicking

Google Earth is basically a huge montage of aerial and satellite photographs overlaid onto a sphere. You can move around, zoom in and out, and the terrain rises and falls on the globe to create mountains and valleys etc. Because it's like sticking photograhphs onto a globe, what you get is a slightly impressionistic view of the world, particularly when flying around. Trees don't stick up. They are flush with the terrain for example, but overall the effect can be spectacular. Many areas, particularly in less developed parts of the world, are pretty low resolution, taken from space, and not particularly detailed.

Here's an example taken from roughly a kilometre above ground level. ( 54°37'22.40"N, 89°24'9.29"E) It's near Chërnoye Ozero in Russia apparently.

A few years ago, more of the map was like this, but google are gradually replacing satellite imagery with much higer resolution aerial photography...

Like this image of Derwent Water in the Cumbria, England. Also taken from about a kilometre above the ground. The co-ordinates for this one are ( 54°34'56.56"N, 3° 7'58.34"W) by the way.

Clicking on either of the pictures will open full sized versions. Obviously the level of detail is much higher using aeroplanes than it is using satellites. High enough to make out cars, people, even sheep in fields. This has led to concerns about security and privacy. Generally google have complied with governmental requests not to use hi res pictures of sensitive areas.

Google earth contains optional layers, often created by its' userbase. You can click on webcams, hi res panoramic photographs, layers highlighting environmental concerns, such as boxes giving emissions data for large factories. Most of these layers will have just a few icons on the globe, but clicking on them gives you the option of showing them all. Clicking on the boxes these open in google earth will often open up a webpage in your browser of choice, giving you further information and links to other similar things.

Most options can be toggled on and off by using the sidebar on the left. This too can be toggled on and off to give you a full screen display, or a mixture of display and options.

There's much more to it, but that'll do for now.

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