Replacement for DAFIF Airspace Data

On Dec 21, 11:01 pm, Tuno wrote:
2KA,

I haven't dived into the gory details of the NASR, but after browsing
the SUA table of the primary data, the format descriptions for all the
tables, and the class B-E shapes in the "Additional" data, I have the
following observations:

* The APT table can be used in conjunction with the FAA NFD (what I'm
using onwww.justsoar.com) to provide the comm frequencies missing
from the latter. (They have a common key.)

* Similarly, the SUA table provides active times missing from the NFD,
for Restrictive, Alert, and MOA areas.

(Alas the good news seems to end there.)

* The SUA table does not provide precise descriptions of the
restrictive areas. Arcs and circles, instead of being described by
[center, radius, begin point, end point, and direction to travel], are
lists of approximated points. They are not suitable for navigation
purposes, and I believe the NASR description even says so.

* The shapes data (for class B-E) have nice vector renderings (I used
TNTatlas), but this data appear to be 2 dimensional only, and also not
suitable for navigation purposes. (To be useful for navigation, top
and bottom elevations must be provided.) It seems this data are useful
only for 2D plotting. Also, at least the Class B file is out of date;
I got the 20 Dec 07 - Feb 08 download, but it still has the old
Phoenix Class B.

I don't want to discourage you from your project, but potential users
should be aware of these limitations.

I do think that creating an airport turnpoint list from the APT table
would be very useful. I hope you don't mind if I add this feature to
what I provide on justsoar.com.

2NO

2NO

What you say about the SUA is absolutely true. The line segments are
accurate, but arcs and irregulars are only approximate. I hope the
FAA will add them.

The shapefile descriptions actually do include the elevation data you
mention, as well as the name of each segment. The shapefiles are
currently beta only; the FAA says they will be official and updated
regularly sometime in mid-2008.

Please do add the airport turnpoint list to turnpoint.com. I'll send
over some of my source code for comparison, so you can see how I
handle things like unique short name generation.

2KA

2KA

Thanks 2KA, I'd love to see your source code for the airport turnpoint
stuff. You can find my e-addy at justsoar.com.

I've completed a program that takes a Cambridge turnpoint file (for
boundaries) and outputs (1) a new version of the same file padded with
all APT entries not closer than a mile to any turnpoint already in the
file, (2) a separate file of the same format with all APT entries in
the same boundary, and (3) a SeeYou (.cup) file with all APT entries
as turnpoints. The last one is nice to load in SeeYou and do whatever
with from there.

The entire APT file creates a file with 13520 turnpoints. And that's
facility type = "AIRPORT" or "GLIDERPORT" only.

Interesting that Turf Soaring (Pleasant Valley Airport) is listed as
an airport and not a gliderport.

Lots of info available to plop into the "Description" field. CTAF and
runway idents?

2NO

Tuno wrote:
Thanks 2KA, I'd love to see your source code for the airport turnpoint
stuff. You can find my e-addy at justsoar.com.

I've completed a program that takes a Cambridge turnpoint file (for
boundaries) and outputs (1) a new version of the same file padded with
all APT entries not closer than a mile to any turnpoint already in the
file, (2) a separate file of the same format with all APT entries in
the same boundary, and (3) a SeeYou (.cup) file with all APT entries
as turnpoints. The last one is nice to load in SeeYou and do whatever
with from there.

The entire APT file creates a file with 13520 turnpoints. And that's
facility type = "AIRPORT" or "GLIDERPORT" only.

Interesting that Turf Soaring (Pleasant Valley Airport) is listed as
an airport and not a gliderport.

Lots of info available to plop into the "Description" field. CTAF and
runway idents?

My priorities are *runway width*, and then 100LL availability (I fly a
motorglider). Here's how John L. does it in the CU cup description:

"RLD, RW width: 100, Fuel: 100LL"

He puts the main airport frequency in the cup Frequency box, and it
would be *very* useful to have the ATIS/AWOS frequency in the description.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly
* "Transponders in Sailplanes" http://tinyurl.com/y739x4
* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

If you want the runway width, do you also want the lengths and widths
of all runways at the airport? (can do, as well as the fuel)

Neither ATIS nor AWOS freqs are in the NASR's APT table -- UNICOMs and
CTAFs only.

Hopefully the NFD will have all the freqs we see on the charts.
(They're supposed to add comm frequencies sometime in 2008.)

2NO

Tuno wrote:
If you want the runway width, do you also want the lengths and widths
of all runways at the airport? (can do, as well as the fuel)

John L.'s solution for SeeYou format was to pick the widest runway for
each airport, then list it's length in the Length: box and width in the
Description: box. That's been adequate for my purposes, and made it
easier for him to produce multiple formats (cup, dat, etc) that didn't
have all the same fields.

Listing all the runways by direction, length, width, and surface (e.g.
RWY 12/20, 2400, 50W, grass) would be quite useful, I think, as the wind
may dictate another choice, and I can't always determine the width from
the air, and for recognizing it more easily.


Neither ATIS nor AWOS freqs are in the NASR's APT table -- UNICOMs and
CTAFs only.

Odd.

Hopefully the NFD will have all the freqs we see on the charts.
(They're supposed to add comm frequencies sometime in 2008.)

I'd love that, so I don't have to dig out a map and find the frequency.
At home, I keep a list on the side of the cockpit, but I travel all over
the country flying from airports as soaring weather happens, so I don't
have a list prepared.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly
* "Transponders in Sailplanes" http://tinyurl.com/y739x4
* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

JL and I think alike. I ended up using the widest runway too for the
runway specified in the length field, and I also specified the longest
runway if more than one at that width.

The descriptions look like this:

"12/30 2000x50ft DIRT"
"C122.8 U122.8 100LL 10/28 4000x75ft ASPH-E"
"C126.1 U122.95 100LL 04L/22R 4401x75ft ASPH-G 04R/22L 4870x75ft ASPH-
G"
"03L/21R 10012x150ft ASPH 03R/21L 9904x150ft CONC"

From left to right, they contain:

[CTAF-freq] [UNICOM-freq(s)] [100LL] [Runway1 ...]

.... where each Runway looks like

[Designation LxWft Surface]

.... and in many cases only one or two of the first three fields have
values.

Does that look useful? Any other suggestions?

2NO

Tuno wrote:
JL and I think alike. I ended up using the widest runway too for the
runway specified in the length field, and I also specified the longest
runway if more than one at that width.

The descriptions look like this:

"12/30 2000x50ft DIRT"
"C122.8 U122.8 100LL 10/28 4000x75ft ASPH-E"
"C126.1 U122.95 100LL 04L/22R 4401x75ft ASPH-G 04R/22L 4870x75ft ASPH-
G"
"03L/21R 10012x150ft ASPH 03R/21L 9904x150ft CONC"

From left to right, they contain:

[CTAF-freq] [UNICOM-freq(s)] [100LL] [Runway1 ...]

... where each Runway looks like

[Designation LxWft Surface]

... and in many cases only one or two of the first three fields have
values.

It's obvious, which is good, except for the E and G after ASPH (for
"asphalt" I assume): G = grass/gravel/?; E = ??

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly
* "Transponders in Sailplanes" http://tinyurl.com/y739x4
* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

2KA wrote:

Please do add the airport turnpoint list to turnpoint.com. I'll send
over some of my source code for comparison, so you can see how I
handle things like unique short name generation.

Speaking of name generation...

I'm probably telling you stuff you know already, but there is the
problem of airports with identical names. I fly from Richland airport in
Washington state, but there are Richland airports in MO, NY, and WI.
John Leibacher solved that for the airport databases he generated by
appending the state name to airports names that weren't unique: Richland
WA, Richland MO, etc.

If you use small turnpoint areas, it may not be problem, but I put the
entire USA into SeeYou, and I typically use large portions of it in
SeeYou mobile, like WA, OR, ID, MT, or WA, OR, ID, northern CA and NV.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly
* "Transponders in Sailplanes" http://tinyurl.com/y739x4
* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org