[photo-3d] Re: Hyperstereo artists?, aerial topography

["Abram Klooswyk" <abram.klooswyk@xxxxxx>]

John A. Rupkalvis 21 Oct 2000:
>These (which very possibly could be the largest single use of 
>stereo photography of all) are the twin pass aerial images 
>made for aerial mapping. They have to be in stereo for 
>drawing isolines on topographic maps, delineating height 
>boundaries.  I understand that the entire United States has 
>been mapped this way.

The entire United States? The entire world you probably mean. 
And apart from airplanes, some satellites are making stereo 
images all day, also this very moment, the circumpolar tracks
form stereopairs 90 minutes apart for example. Some of the most 
detailed images are held secret, having military significance, 
but some are publicly available. 

The topographical institutes of many (at least the western) 
countries have files of mostly 60% overlapping air photographs 
which often go back to the 1920-30s, and are often repeated 
every 5 or 10 years, depending on population density and wars. 

Already since many years I have some of these vertical aerial 
stereopictures of my house with surroundings. I just had to 
give the topographical coordinates to our national topographic 
institute and could _borrow_ the picture set for free to copy 
them (this is no longer possible now in this country, you have 
to buy prints :-(). 

Depending on security restrictions, I guess that you can order 
similar aerial stereo pairs from your living area.

Abram Klooswyk