Dallas wrote:
On 10 Jul 2008 12:09:47 GMT, Robert Moore wrote:

Just to not confuse those that don't know, the yellow on the
sectional chart indicates the area that could be expected to be
illuminated at night by street lights, lights in buildings, etc. It
is an aid to night visual navigation.

I found a reference which doesn't state it that way. Mine you, this
reference just comes from a post in another forum, but he claims to
quote the map makers:

"The "yellow" area on the charts is supposed to correspond to
developed urbanized areas. The only significant change regarding
charting in these "yellow" areas involves the depiction of
obstructions. Generally, obstructions 201' and higher above the
ground are depicted on the charts. However in these "yellow" areas,
only obstructions 300' and higher above the ground are depicted.


Seems to me the developed urbanized areas are the areas that could be
expected to be illuminated at night by street lights, lights in buildings,
etc.