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[aprssig] Re: TIGER maps what-s the problem?

VE7GDH ve7gdh at rac.ca
Sun Jun 18 19:16:47 UTC 2006


Bob WB4APR wrote...

> In an airport? At the convention center? On the subway?
> My D7 fits in my shirt pocket (with slim-line battery). A GPS
> does not work indoors, and the wire is a cumbersome entrapment.
> Yes, you and I do use APRS quite diffrently. But APRS must
> accomodate ALL users, not just favorite modes. Hence
> it must allow for users without GPS.

This is getting kind of ridiculous, but here goes anyway. Perhaps you didn't
read where I said...

   "I don't have a D7, but about the only time I can think of that I would
    manually key in a position would be if I absolutely had to send a
    message and I was indoors and the GPS couldn't acquire a fix. "

Remember... no one is telling you that you HAVE to use a GPS - whether you
are indoors or outdoors. I just said that I would find it quicker to plug a
GPS in than to manually key in a position. Maybe you need BPS™ (ball
positioning system) instead of GPS - hi! www.radargolf.com However, unlike a
D7, they say that BPS should not be used indoors!

> If you depend on GPS to do that <beacon a position>, then I fear
> that in many travel situations (besides a car) you are probably
> often beaconing the *wrong* precise (last aquired) position. I
> prefer to enter a manual posit with an ambiguity covering the
> area where I am wondering (including indoors) so that somone
> can see where I am generally, and not be incorrectly
> lead to a past precise position where I am not.

Now you are stepping over the line. I have never beaconed a "wrong" position
(other than playing around with "ambiguous positions" yesterday). OK... the
odd time I might have manually entered an incorrect position, but it was
immediately noticed and corrected. your fears are unfounded and frankly,
quite silly. You seem to be imagining that I or anyone else operates exactly
like you. Again, I don't have a D7. IF I did, and IF I needed to enter a
position manually, I would enter it as precisely as I could. If a GPS was
able to operate where I was, I would use it. Nothing that I have will beacon
a "past precise position" unless set improperly. What could beacon a "past
precise position"? I suppose a TinyTrak 3 set (improperly as far as I'm
concerned) with "only send valid" NOT enabled. A TNC used as a tracker
(ancient history and really not recommended in populated areas) not
programmed properly... e.g. KPC-3+ with a GPS attached and not having
CLEAR in the BLT settings so that copies of (old) NMEA strings could be
transmitted. Anything else? Well, I have seen D7s and D700s saying they
were at home instead of where the attached GPS would have said that they
were but that was operator error. <g>

No one is tell you that you are "doing APRS wrong" by manually entering a
position - ambiguous or not - but you seem to be trying to tell other APRS
users how to operate. Please don't try and say that I am beaconing "wrong"
positions. OK... you didn't say that I was beaconing "wrong" positions but
you said that you "fear" that I am. Fear not.

Besides... I navigated just fine for years before consumer grade GPS
receivers were available, i.e. with a map and a compass. Whether hiking or
skiing, the map and compass were mandatory equipment. For me, starting about
12 years ago, the became an additional piece of mandatory equipment. That
doesn't mean that I stopped knowing how to use a map and compass - I just
had to use them less often. Whether I am sighting two landmarks with a
compass, looking at a street map or watching a GPS, it is seldom that I
wouldn't know EXACTLY where I was if I needed to know. If you want to enter
a non-precise location in your D7, that's up to you - whether it is because
you just don't know exactly where you are, or whether you don't want to
beacon your exact position, or whether it is just quicker to enter an
ambiguous position. Again, no-one is telling YOU how to operate.

> I can visualize you now, a GPS on your head with a wire
> hanging down to a D7 clipped to your belt and a
> full size whip dangling off to one side... (chuckle)...

Now you are getting silly again. Well, I have actually mounted a GPS on my
helmet when skiing on occasion. In dense tree cover, it does a bit better
with the GPS level instead of on the shoulder strap of my backpack where it
only sees about half of the sky. This was however before I became an APRS
user. I doubt if I would be hiking or skiing with a "full size" whip but I
do have some super-flexible quarter wave antennas that are used on occasion.
If I had a D7, the more likely scenario would be that the D7 would be in a
pouch on one shoulder strap and the GPS would be in a pouch on the other
shoulder strap. The wire in between would be held in place by Velcro. Down
the road, maybe the D7 will have a GPS receiver built in as it should have
had from day one or it will become blue-tooth capable. If I had a D7 and was
wandering (not wondering - hi!) about in an airport or a subway (I shudder
at the thought... I would rather be in the hills skiing, hiking or biking)
the D7 wouldn't have a GPS connected. They tend to not work very well when
they can't see the sky.

> Well, I like to travel light, with my D7 in my breast pocket
> whenever I am traveling through airports and public
> transportation. I can whip it out at anytime to send a
> message back to the wife on delays, re-routes, and travel
> changes. I would find it a big inconvenience to have to
> carry a laptop and a GPS just to send an email message
> from my HT.

I like to travel light too. I carry the laptop because I have to... not
because I want to. These days, the only time I don't have a laptop or a
bunch of PCs in front of me is when I manage to escape for a bike ride and I
haven't been able to do that enough recently. When I have the laptop with
me, I just have more options than you do. I really only consider it
"travelling light" when I don't have the laptop with me.

> We are quite different. To me, APRS is a communications
> system. When I travel it is for communicating not only
> back home but also with other local APRS users nearby.
> Although precise positioning is a capability of APRS, I
> simply do not get so dependent on a GPS and precision
> that it gets in the way of just doing what I am doing
> and communicating.

It must be a matter of opinion. I use a GPS because I have one (well, more
than one) and it works. GPS makes a precise location (limited by all of the
usual... SA if ever implemented again, accuracy of the GPS receiver itself,
multi-path etc.) easy to do. I can understand your need to enter a
non-precise location so you can send a message from your D7. I can
understand you entering a non-precise location when hiking because you want
to travel light and don't want any dangling wires. Having or not having a
GPS would not get in the way of doing whatever I was doing or in
communicating. It is just a tool that I will make use of if it's available.

> APRS was designed to cover as many different ways
> of operating as possible including manual positioning
> and position ambiguity.

I'll go along with that.

> Each individual may only use a few capabilities, but
> that does not mean that the other capabilities should be
> denied or ignored in software clients. Especially if ignoring
> these fundamentals leads receipents to false, incorrect,
> missleading displays of a sender's intent.

I think I can fairly safely translate "software clients" to mean UI-View.
However, the number of times I have looked at a station's position and been
affected by that station having intentionally entered in non-precise
position is exactly ZERO. I have seen a few imprecise locations, but they
were cars and houses hundreds of km away from their real location up in the
hills or out at sea. I think those occasions have all been explained by
either trackers or TNCs that were beaconing invalid positions by not having
"valid only" selected or occasionally by manually entered positions that
were entered erroneously. Possibly a few times were caused by severe RF
problems with too much RF messing up a tracker. 99% of the time, it only
takes a glance at the digi path used to prove that they weren't up in the
mountains or bobbing around off-shore.

Should any APRS clients released down the road be able to handle ambiguity?
Yes. Will UI-View ever be updated to handle ambiguity? Not by Roger G4IDE.
Can an add-on allow it to indicate ambiguity or cause a position-less beacon
to show up on my station list? I don't know.

I still haven't remembered what this has to do with TIGER maps though! Let's
just agree to disagree and each use APRS in the way that we want to use it.

73 es cul - Keith VE7GDH
--
"I may be lost, but I know exactly where I am!"





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