He also debunked the myth that the yellow areas were ever used for night flying - saying that was never the case.
There is no explicit explanation saying "we use yellow because...". The reason for this color being chosen is really not known. They've been doing it since day one on sectionals (Late 60's for Washington, for example). It was established by the powers that were, at that time...Dept of Commerce...FAA....Military, and whoever else was involved. As Jeff said, there is no authoritative source saying that yellow mimics light...not even in our specs. That being said, we're left to our logical explanations for them choosing yellow...which was touched upon in this thread....mainly due to light emitted from populated places. I personally believe they chose yellow because it best mimics light emitted from these populated places...at night in particular. With regards to the outlines of these populated areas & cities, we do update them as often as possible. This is primarily done thru satellite imagery. The frequency of these updates depends of how often we get updated imagery. And its nothing fancy...we dont have any special sources providing this for us. Personally...I use google earth for my chart *shrug*..Others use Terraserver...some use Globe Explorer. Quite often we cross reference these sources as well. I have been on a test team to try using imagery from other sources coupled through our GIS software...so other options are still in the works. Also, we have our flight edit program. These guys fly around in a King Air and verify what we have charted, including city tint/outlines. If they see populated areas that are in need of updating, they give us a rough depiction of what the area should look like. For the those interested, check out the city tint/outline for Harrisonburg, VA on the next edition. It's gotten much bigger based on the latest imagery I received, and has been changed accordingly. I'm gonna post a screen shot of the change I called for. And this was based on the latest imagery from Google Earth, so you can actually see my reasoning for doing such. Chart change: http://i14.tinypic.com/4ujs5y9.jpg Based upon: http://i19.tinypic.com/4umz67s.jpg *FYI, for the local guys, or anyone using the washington secional: The 82nd Edition will be delayed until August 30th. So you can ignore the expiration date of 8/2. A notice will be published. And NO, the new, delayed chart WILL NOT have the new ADIZ...go figure I'll bet my money that they will make the changes shortly after August 30th...and have to re-issue the chart
Cities and large towns are a yellow rectangle and Large cities are noticeably yellow in color and are supposed to have the general shape of the city at night.
What is glare like for a tablet in an open-cockpit legal eagle? Is it still pretty readable dawn-to-dusk?
