Here are some movies that show the relationship between contours and topography.
Most of them are more than 1 MB, so if you have a dialup or otherslow link it will
take awhile to download them. You must have Quicktime installed in order to view
them. You can download Quicktime free for Windows or Mac from Apple at http://www.apple.com/quicktime/products/qt/
All are available as Quicktime movies or as mp4 movies. Quicktime files are larger
and take longer to download. The latest version of Quicktime will play mp4 movies,
so it is recommended that they be viewed if possible.
This animation slowly adds shading to give a 3D perspective to the contours.
These two animation movies show the water level rising to flood the topography,
illustrating the concept of contour lines as 'intersection of the landscape with
a level plane', in this case creating shorelines with the rising water.
The interactive movies are large size, but may not play on all computers, although
they should with the latest version of Quicktime.
To change the water level in the interactive animation, move the hand cursor
up and down with the right mouse button held down. Or click on the red arrow to raise
the water stepwise, one-half contour interval at a time.