Over maps, envisioning the atmosphere


The idea is to take an ordinary road map and envision the stuff which lies above it. One takes various altitudes of interest, and figures out how far above the map they are, given the map's scale.

For example, say a map of Massachusetts is hanging on a wall. Its scale is something like 1 inch for 10 miles.
Now one factoid of interest is that most all weather lies below an altitude of 7 miles. 7 miles is a bit less than 1 inch. All weather is within an inch of the map! All clouds, storms, etc are in that shallow area above the map.
A perhaps surprising result.
90% of all air is within that inch, with the rest of it dribbling off for a foot or so.
FAA regulations require pilots to use oxygen above a quarter of an inch.
Humans cannot survive unaided above 3/4 inch.
Low earth orbit, and the space shuttle, are around 1.5 feet from map.

More generally, when using a map, one can envision the third dimension. With a street map, the buildings. With a subway map, the city above. And more generally still, when using any representation, it can be interesting to envision some of the dimensions which have been sacrificed.

For another example (rather crufty), there is the map below. Its scale is about an inch for 10 miles. I've sortof tilted the map down, and added some altitude stuff to scale on the side.
Some weather information from http://www.atmos.uiuc.edu/.
Map from http://www.mapquest.com/.
Regrets: Cloud height numbers are for bases. Mt Everest is far far flatter, so here I am reinforcing a common misconception of mountain pointiness.

I still haven't found a good online orbital picture of clouds and their shaddows. Here are some approximations...

Possible improvements for this page:
Clean up boston example numbers.
Get good cloud numbers, rather than the current _base_ of clouds.
Add a narrower scale map example. Metro boston for instance.
Flesh out a list of interesting heights...
thing km miles feet
FAA requires pilots use suplementary oxygen above 14,000 ft. 4.2 km 2.7 mi 14 kft
Earth's moon 190,000 km 120,000 mi 630 Mft
... km mi kft
How fast does the terminator rise at sunset?

Comments encouraged. - mcharity@lcs.mit.edu.
1997.Jul.19  Added `clouds and their shaddows' images.
1996.Dec.05  Light dusting.
1996.Nov.17  Some work.
1996.Nov.15  Begun.