In looking at the Antarctica and Arctic in Google Earth the shore portions are mapped but the middle seems to be mostly a featureless whitish grey surface with almost no detail. Is this the real surface or is it simply unmapped at this point?
Well, the Arctic is ocean, and the oceans on Google Earth are mostly just blue fill draped over a relief map of the sea bed.
I’ve noticed that land close to both poles (e.g. northern Greenland and the Canadian Arctic Islands) shows up pretty distorted on satellite imagery, often breaking up into “strips”, with clear images only in those parts with aerial photography. I believe this is because of the orbit of the satellites - the view of polar areas is very oblique.
I don’t know, but this was what I came up with from googling, so you may want to just drop the topic :eek:
Actually I realised I’m talking about Google Maps, where a lot of the distortion is probably due to the stretching to fit a rectangular map projection. I don’t have Google Earth on this computer, so can’t check, but the imagery of Antarctica looks genuine, if low-res. Satellites in polar orbits can of course cover the polar regions.
I just checked, and it seems the interior of Antarctica is just “filler”. If it is actual, it is very lo-res.
They have low res imagery only for most of the Arctic and Antarctica, but they do have higher res images of places with permanent settlements. They even have street view in Antarctica.
And as colophon points out, there are some differences between Google Maps and Google Earth when it comes to areas close to the poles.
I do recall seeing an application called Google Ice which, like Google Moon and Google Mars offered a custom overlay of antarctic imagery. But a quick search turns up nothing, so it probably was not an official google project.
If you zoom into the North or South Pole in Google Earth, the display frizzes out looking straight down and converts to “street view” (FWIW) and looking out towards the horizon. I note my computer’s fan starts going wild at this point (I guess because of all the meridians coming together?). I note that neither overhead view or a street view of Scott-Amundsen base does *not *show up on Google Earth
I punched the base coordinates Latitude / Longitude base coordinates
-90.000000 0.000000
into the Google Earth address bar at the top left then zoomed in. It was like Google Earth was finding God.
Oh, the traffic is terrible!
So, what’s God like at the South Pole? Is it like Dante’s The Empyrean in Paradiso?
I love that in the bottom right corner panel, the orientation indicator is a penguin instead of the usual little orange man.
Ok, Try this. Hit Control L to turn on lat and long lines.
Zoom in close to the north pole and angle down for an oblique view.
There is definitely some kind of cone structure built by aliens there.
Mine turns into a cone and then the screen goes spastic because of the longitude lines.
He said something about wanting a starship.
Mine Gott, Vat haf I dun!
Not only that, but the particular projection used by Google Maps makes it impossible to show the poles themselves. It uses some variant of the Mercator projection, whose linear scale becomes infinitely high at the poles.
Geosynchronous satellites are pretty useless for mapping, they are too high for good detail and have a limited footprint. Much lower altitude polar orbits are used, which allow the satellites to cover the entire earth (not at the same time though!). In the case of weather satellites, the images are raster scanned. The orbit does the vertical scanning and the horizontal scanning is done either by a spinning mirror or the entire satellite is spun. The orbits are chosen so that scans just overlap at the equator and this means that there is great overlap at and near the poles. This would have the potential of much greater resolution if digital filtering were used to exploit the redundancy, though there is not high demand for detailed polar images, so this seems to to be done.
Not “some variant of”-- The exact Mercator Projection itself. Mercator is seriously over-used, and there are very few situations where it’s actually appropriate, but Google Maps is one. There’s only one projection where longitude lines are vertical, where you can zoom in, and where the distortion goes to zero in the limit of extreme zoom, and that’s Mercator.
That’s not what I’ve read. Every cartographical source I’ve come across claims that Google Maps uses the Spherical Normal variant of the Mercator projection. See for example OpenLayers’s discussion of the projection, or this one from the Barcelona Field Studies Centre, or this blog entry from a computational cartographer. Even Wikipedia’s article on Google Maps is careful to point out that the projection isn’t standard Mercator.
I’m not sure what that means. Does that just mean that the globe is normalized to a sphere before the Mercator projection is applied? I was neglecting any deviations of the globe from a sphere.