On 09/19/2011 04:07 PM, HB-GRAL wrote:

> To improve our map resources with further data I started an experiment 
> with free available airspace data. Actually this is far from being a 
> good map and finished design, it is just a start to implement 
> (unofficial!) airspace information:
> http://maptest.fgx.ch/navaid.html
> 
> I need probably some advice from real pilots around here for what is 
> useful to map for FlightGear airspace, and how this should be displayed. 
> I think I am aware of regular ICAO graphics definitions etc. But I dont 
> want to design well known (and also free available) maps, I just want to 
> develop a design as a "overview" and some really necessary items i.e. 
> for learning the basics or whatelse. There is no RFC for what I am doing 
> here, I am just playing around with data and an new Mapnik Server and 
> ask for discussion and contribution.
> 
> (Notice, my new signature since I send this links to the list and 
> elsewhere: Please do not use any of this material for real navigation! 
> NEVER. Do only use this to help developing and improving the design of 
> my maps ;-).

A few remarks:

1) Real pilots are concerned about airspace, but they are also
 concerned about terrain and obstructions.  Also weather and 
 winds aloft.  You don't want to follow the example of Cory Lidle 
 and his instructor.  Their flight path was compressed by airspace 
 and they ended up flying into the side of a high-rise apartment 
 building.  Violating the airspace would have been a better choice.

2) It is good to provide disclaimers, and people should take those
 seriously.  However:
 2a) Pilots are trained to cross-check everything, and never rely 
  on a single source of information.
 2b) People *are* going to use whatever maps they can get their hands
  on -- in conjunction with other information -- to help with real-world
  flight planning and training.

For example, I commonly use FlightGear to familiarize myself with the
IFR approach procedures and other details before flying into an unfamiliar 
airport.  Of course I crosscheck the apt.dat description of the airport 
against satellite photos et cetera.  Discrepancies abound, as previously 
described.

3) Interactive computerized maps offer some treeemendous advantages.  For
 one thing, the ability to turn layers on and off is very powerful.  The
 total amount of detail that is /sometimes/ useful is more than can be
 shown on any one map.

 Here's a rough scenario, aka "use case":

  1) Turn on airport names (not just 4-letter identifiers) because I have
   not memorized every identifier in the world.

  2) Sketch a rough route.

  3) Turn off the names, to declutter the map.

  4) Turn on navaids, intersections, and fixes, so as to facilitate defining
   the route in terms that can be used on an ATC flight plan.

  5) Turn off everything but the route and the terrain, to see what sort
   of obstructions there are.

  6) Apply safety margins required by regulations.  Apply additional personal
   margins.

  7) Revise the route to get around the worst of the obstructions.

  8) Cross-check against the VFR sectional, IFR enroute chart, et cetera.

  9) Go back to step 4 and iterate.

 10) Turn on weather and winds aloft.

  *) et cetera.

Note that I have a tool that not only highlights the route centerline, but
also the /corridor/ extending some distance on either side.  For example, a
half-width of 4 nm is relevant to FAR 91.177.
  http://www.av8n.com/fly/grass-intro.htm#fig-colored-fix-pass

These tools are painfully difficult to use.  The only thing that would be
worse would be not having them.  Flight planning is relatively easy if you
stick to IFR airways, but sometimes in mountainous regions (e.g. Alaska
among many others) this can lead to insanely high MEAs (minimum enroute
altitudes).  As soon as you start planning an off-airways flight, trying
to do it just by penciling in lines on a chart is exceedingly laborious 
and error-prone.

So, you have to decide what you want to do.  You could go for a map that
is merely pretty to look at ... or you could go for a map that is actually
useful.

One more thing:  You don't want to go too far with the disclaimers.  Lives
are at stake, and /not/ providing information can be just as much of a
problem as providing not-quite-perfect information.  CFIT i.e. controlled
flight into terrain makes a large contribution to the fatal accident rate.
Sometimes a contributing factor is compression between airspace or weather
above and terrain below ... but sometimes it just comes down to bad planning
and really bad luck.  Providing something that helps with this would be a
Good Thing.

Again:  It doesn't have to be perfect.  Note that the FAA provides (via
contractors) a service that will prepare a computerized flight plan for
you.  There are scenarios where you can file such a flight plan, get 
cleared "As Filed", and fly it as cleared ... and fly right into the side 
of a mountain.  Hence the need for cross-checking.

This probably isn't the ideal forum for discussing such things.  There is
a lot of information available on this general topic.  I get 150,000 
hits from
  http://www.google.com/search?q=google-earth+flight-planner

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