Great Circle mapper; sci.aeronautics.airliners WWW page news
Karl Swartz
In May, 1994, Terry Drinkard started a thread on Really Long Range
Commercial Transports. That sent me scurrying for my atlas and to
find an equation for computing great circle distances, and was the
genesis of a much larger project -- not just to compute distances
along a great circle route, but to show them on a map.
Well, nearly two and a half years later, the fruits of that project
are ready for the world. The latest addition to the collection of
WWW pages for sci.aeronautics.airliners is the
Great circle flight path display
The URL for this page is http://www.chicago.com/airliners/gc.html.
If you don't feel like exploring by yourself, try the following:
http://www.chicago.com/cgi-bin/gc?range=7750nm,8700nm@SFO
http://www.chicago.com/cgi-bin/gc?path=HKG-SCL,HKG-EZE
The first illustrates the range of the proposed 747-600X and -500X,
respectively, from San Francisco. The second shows some of the more
remote routes I've seen that are at least plausible. (Santiago and
Buenos Aires from Asia came up in the 1994 discussion.) HKG-SCL is
just a bit shorter than the unlikely New York to Perth, but unlike
the latter route it isn't even close to being flying with ETOPS. I
hadn't realized that in 1994 but HKG-SCL/EZE covers some incredibly
desolate expanses of the world.
ETOPS maps will be added to these pages soon. Right now, I've got
some holes in the alternate airport database which must still be
filled. If anyone has a good list of ETOPS alternates, especially
for some of the obscure places like military bases on islands way
out in the oceans, I'd very much appreciate your help.
On the subject of the sci.aeronautics.airliners WWW pages, people
sometimes ask what my involvement is with the airline(r) industry.
Professionally, none -- airliners are just an interest. I work for
a company called Network Appliance, which makes filers ("network
file server appliances"). On September 3rd, we announced the Web
Filer, new software that allows our filers to act as WWW servers.
A few days before that, my own WWW server, including the newsgroup
WWW pages (http://www.chicago.com/airliners), became the first Web
Filer site on the Internet. Alas, this is only a test project for
me to use in developing an application note, and to get some good
testing on our new product, so within a few weeks the pages will
move back to their old FreeBSD/Apache server.
--
Karl Swartz |Home k...@chicago.com
|Work k...@netapp.com
|WWW http://www.chicago.com/~kls/ *** #1 Web Filer! ***
Moderator of sci.aeronautics.airliners -- Unix/network work pays the bills
Bill Frensley
In article <airliners...@ohare.Chicago.COM>, k...@ohare.Chicago.COM (Karl Swartz) writes:
|> In May, 1994, Terry Drinkard started a thread on Really Long Range
|> Commercial Transports. That sent me scurrying for my atlas and to
|> find an equation for computing great circle distances, and was the
|> genesis of a much larger project -- not just to compute distances
|> along a great circle route, but to show them on a map.
A few years ago I was looking through an almanac and found a table of
airline distances between world cities. The longest distance listed was
Bangkok to Lima, Peru, which was a bit over 12000 sm (i.e. nearly half
of the earth's circumference). I got out my globe, placed an index finger
on each of the said cities, and the sphere was balanced. Are there any
other "antipode pairs" of major cities? And how plausible would airline
service between them be?
--
Bill Frensley
Electrical Engineering
University of Texas at Dallas
P.O. Box 830688, MS. EC-33
Richardson, Texas 75083-0688
Karl Swartz
[This is drifting away from aviation -- is there any newsgroup
appropriate for maps and cartography?]
>I have seen (in a restaurant!) a large number of maps each of which
>was centered on a major world city and any straight line form which
>was a great circle.
That would be a map drawn using an orthographic projection, in oblique
form unless you center on a pole (polar) or the equator (equatorial).
The reference section of the Perry-Castaneda Library Map Collection
has a nice description of this and other projections -- look at
http://www.lib.utexas.edu/Libs/PCL/Map_collection/Cartographic_reference.html
> Does anyone know where I can buy such maps?
Polar ones shouldn't be too hard to come by, but finding good ones
based on arbitrary centers might be a challenge.
> Does anyone know of any PC or workstation software that generates
> such maps?
Some of the PC mapping software might be able to do this for you but
I don't know much about those packages. For workstations, various
mapping tools can be found on the net but they're essentially kits,
with some scavenging needed to collect the data and glue everything
together, so you'd have to want these maps pretty badly.
The most popular WWW mapper, at Xerox, has several projections but
orthographic isn't one of them. Several other WWW sites do support
this projection:
http://www.aquarius.geomar.de/omc/
This generates nice maps, but the interface wasn't thought out
clearly for the orthographic projection -- you specify the top
and bottom latitudes for the map, which is fine for rectangular
or Mercator projections, but nearly meaningless for orthographic
which most logically is based on a center point. (The comments
indicate the author is aware of the need for some interface
enhancements.) With some tinkering (try N=90, S=89.99, E=180,
W=180 for the north pole, almost) you can get something decent.
http://www.neosoft.com/~forge/java/Cartog/Cartog.html
If your browser has Java support, the Cartography Applet is nice,
if a bit slow to load, and it can do orthographic projections
based on any center point you choose.
http://puddle.mit.edu/jg/mapoptjg/
This also works from a center point and can do orthographic maps.
It's not as refined as the other two, but works reasonably well.
--
Karl Swartz |Home k...@chicago.com
|Work k...@netapp.com
|WWW http://www.chicago.com/~kls/
John Ahlstrom
In article <airliners...@ohare.Chicago.COM>, k...@ohare.Chicago.COM (Karl Swartz) writes:
>In May, 1994, Terry Drinkard started a thread on Really Long Range
>Commercial Transports. That sent me scurrying for my atlas and to
>find an equation for computing great circle distances, and was the
>genesis of a much larger project -- not just to compute distances
>along a great circle route, but to show them on a map.
I have seen (in a restaurant!) a large number of maps each of which
was centered on a major world city and any straight line form which
was a great circle.
Does anyone know where I can buy such maps?
Does anyone know of any PC or workstation software that generates
such maps?
Thanks
--
John Ahlstrom jahl...@cisco.com
408-526-6025 Using Java to Decrease Entropy
Any neural system sufficiently complex to generate the axioms
of arithmetic is too complex to be understood by itself.
Kaekel's Conjecture
Keith Brewster
In article <airliners...@ohare.Chicago.COM>,
Karl Swartz <k...@ohare.Chicago.COM> wrote:
>[This is drifting away from aviation -- is there any newsgroup
>appropriate for maps and cartography?]
>
>>was centered on a major world city and any straight line form which
>>was a great circle.
This is a topic important for radio communication.
There is PC software written by amateur radio enthusiasts to do this.
I suggest checking the amateur radio newsgroup(s) for recommendations.
-Keith