in case anyone is interested, those areas In ATC-speak are called approach and departure "corridors". If you know the direction of the wind, (and of course, you should,) you can probably determine which corridor is being used on any given day. On the takeoff side, the crew will climb quickly for noise-abatement reasons so that side will rarely be an issue. On the approach end, using 300 feet per mile, you can get pretty close to the glideslope altitude (where the landing aircraft will be.)
Here is an example of an ILS approach (Instrument Landing System) to Memphis runway 36L. (For those who aren't aware, runway designations are determined by their magnetic heading +/- ten degrees.) The "feather" you see pointing north along the runway centerline is the path the aircraft will follow for landing. Down below is the "profile" view of the approach and here you can see the altitudes during the descent to landing. So those blue/gray areas on the Go4 map correspond to these "feathers" and will be depicted for every runway that is used for takeoff and landing. BTW, this is a Jeppesen "approach plate."
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