Celestial Navigation

(Abdul Ahad) wrote in message . com...

I wonder if some day GPS references might replace street names and
people's home addresses. It may look more convenient in the modern
fast moving, computerised world to do that!

How do you figure that?

GPS does not have enough resolution to identify individual
houses. Accordingly, it cannot be used for addressing
them.

I recently spent a week in Costa Rica, which (like
many Latin American countries) doesn't use street
numbers, but instead specifies locations as distances
from landmarks. My San Jose hotel address was "250m
west of the country club, old highway to Santa Ana,
San Rafael de Escazu".

I'll stick to street numbers thanks.

Laura Halliday VE7LDH "Que les nuages soient notre
Grid: CN89mg pied a terre..."
ICBM: 49 16.05 N 122 56.92 W - Hospital/Shafte

Barry Schwarz wrote:

On 18 Mar 2004 09:04:36 -0800, (Laura Halliday)
wrote:


GPS does not have enough resolution to identify individual
houses. Accordingly, it cannot be used for addressing
them.

Why not? Mine is an el cheapo and is good to 7 meters. That should
be adequate for most except that really narrow house they always point
out on the canal tour in Amsterdam.

At any rate by taking repeated readings from a fixed location (or
preferably from a few, several metres apart) one can improve the
precision a great deal, as the random errors tend to cancel out.

--
Odysseus

Martin Frey wrote in message . ..
(Abdul Ahad) wrote:

At the risk of sounding old fashioned, I think I prefer to keep my
sundials, sextant, moving needle compass and wind up watches, as
they:-

"...call back a time when there was flowers all over the Earth and
there were valleys and there were plains of tall, green grass that you
could lie down in, that you could go to sleep in. There were blue
skies and there was fresh air and there were things growing all over
the place - not just in some domed enclosures blasted some millions of
miles out into space!" - 1970s movie "The Silent Running".

And you'd better enjoy every minute of it because disease and insecure
food supplies killed most of the inhabitants of this Utopia before
they reached 35.

True. But you probably died with less stress.
There were blue skies and there was fresh air...

On 18 Mar 2004 09:04:36 -0800, (Laura Halliday) wrote:

GPS does not have enough resolution to identify individual
houses. Accordingly, it cannot be used for addressing
them.

Many inexpensive GPS receivers are WAAS enabled, which gives them an accuracy
better than 3m in North America. That should be plenty good for locating a
house. Even non-WAAS receivers will usually be within 10m, which is also good
enough in most cases (although a backup numeric address wouldn't be a bad idea).

Indeed, I have seen some stores that provide GPS coordinates along with their
regular address.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

(Laura Halliday) wrote in message . com...
(Abdul Ahad) wrote in message . com...

I wonder if some day GPS references might replace street names and
people's home addresses. It may look more convenient in the modern
fast moving, computerised world to do that!

How do you figure that?

GPS does not have enough resolution to identify individual
houses. Accordingly, it cannot be used for addressing
them.

My eTrex pocket GPS gives an optimum accuracy of +/-5 metres when
there is smooth terrain and good triangulation with at least 4 or 5
satellites scattered in the local sky view. I made thorough use of it
in Florida last September -
http://uk.geocities.com/aa_spaceagent/florida2003.html

I also read somewhere military GPS service provides even greater
accuracy than the civilian version (precision guided missiles, etc
will need them), so the potential is there for resolving even the
smallest house.

(Abdul Ahad) wrote:

I also read somewhere military GPS service provides even greater
accuracy than the civilian version (precision guided missiles, etc
will need them), so the potential is there for resolving even the
smallest house.

Didn't the Clinton administration remove this selective filter? I
thought we all had access to th same info now.

--
Martin Frey
http://www.hadastro.org.uk
N 51 02 E 0 47

"Martin Frey" wrote in message
...
(Abdul Ahad) wrote:

I also read somewhere military GPS service provides even greater
accuracy than the civilian version (precision guided missiles, etc
will need them), so the potential is there for resolving even the
smallest house.

Didn't the Clinton administration remove this selective filter? I
thought we all had access to th same info now.
Not quite.
There are two different 'errors'. Selective availability (which was turned
off), added a deliberate shift to the data being sent, degrading accuracy.
Seperately, there are inherent errors associated with atmospheric signal
distortion etc.. The military system uses a second set of frequencies to
reduce these errors. This latter improvement is not available on the
civilian system. SA, had been rendered fairly useless, since sytems using a
local receiver, rebroadcasting the current 'error' at a known site, had
effectively removed it's effectiveness (DGPS). DGPS systems offer accuracies
in some cases to centimetre levels. Versions using a 'wide area' correction
(not so accurate, but simpler to use - WAAS), allready easily exceed the
ability to discern individual houses. Systems using this ability, can
happily tell which side of a single carriageway road you are on.
That having been said, though I like lat/long coordinates (and if somebody
is trying to tell me how to find their house, I'll normally just ask for the
coordinates), an address is more memorable/easier to use most of the time.

Best Wishes

On 18 Mar 2004 09:04:36 -0800, in uk.sci.astronomy ,
(Laura Halliday) wrote:

(Abdul Ahad) wrote in message . com...

I wonder if some day GPS references might replace street names and
people's home addresses. It may look more convenient in the modern
fast moving, computerised world to do that!

How do you figure that?

GPS does not have enough resolution to identify individual
houses. Accordingly, it cannot be used for addressing
them.

Eh? Mine frequently pinpoints me to within a few metres, certainly
accurately enough to find my house.


--
Mark McIntyre
CLC FAQ http://www.eskimo.com/~scs/C-faq/top.html
CLC readme: http://www.angelfire.com/ms3/bchambless0/welcome_to_clc.html


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On 18 Mar 2004 21:51:05 -0800, in uk.sci.astronomy ,
(Abdul Ahad) wrote:

I also read somewhere military GPS service provides even greater
accuracy

No need for military hardware - DGPS will pinpoint you to within a metre.
--
Mark McIntyre
CLC FAQ http://www.eskimo.com/~scs/C-faq/top.html
CLC readme: http://www.angelfire.com/ms3/bchambless0/welcome_to_clc.html


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On Thu, 18 Mar 2004 16:40:39 +0000, in uk.sci.astronomy , Martin Frey
wrote:

(Abdul Ahad) wrote:

"...call back a time when there was flowers all over the Earth and
there were valleys and there were plains of tall, green grass that you

And you'd better enjoy every minute of it because disease and insecure
food supplies killed most of the inhabitants of this Utopia before
they reached 35.

So you prefer to live to 80 in a trashcan?
And remind me, Copernicus? Gallileo? Socrates? Died at 35?

--
Mark McIntyre
CLC FAQ http://www.eskimo.com/~scs/C-faq/top.html
CLC readme: http://www.angelfire.com/ms3/bchambless0/welcome_to_clc.html


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