I thought that it would make sense to look at the Aeronautical Chart Users
Guide, which is published for the specific purpose of answering questions
like this.

In the section "VFR Aeronautical Charts," under "Culture," we find that the
yellow areas represent "Cities and Large Towns," with a larger blotch of
yellow identified as "Large Cities." Nothing about lights or anything other
than population.

I tell my students to pay no attention to the boundaries of the yellow
blotches, because there is no way to identify city limits from the air, and
towns/cities simply change too fast for chart designations to make any
sense. The only practical use of the yellow blotches is, in my opinion, to
identify places where it is going to be difficult to find a place to land
(in-town airports excluded).

Bob Gardner

"Teranews" wrote in message
news:1119295818.456e1bd0d1dc4312bea6e25f65e9e825@t eranews...
A pilot recently asked me a question, that I cannot find the answer to.

On a sectional chart, around cities, are yellow areas.
What are they?
Where on the legend can this be found?

My answer was "congested areas of a city or town" which I though sounded
official
enough to work. Ah-Ha, he says, "Show me."

The specific area in question is just south of Sunriver, on the Klamath
Falls sectional. (DSD 175 @ about 25nm) I've flown over it, and it is a
combination of golf courses.

Over beer last night, one fellow suggested that it is marked that way
for "National Security Reasons".
Wink, Wink, nudge, nudge, "You are not supposed to ask.", "Why do you
think they left it off the legend."

Am I just blind? Is the print too small? Can anyone else find it on
the legend?

Al Gerharter