From Sweden:

Hello!
We are two students at the university of Linkoping in Sweden, writing
two
essays for our county-museum. Outside town there's an area (about 7*3
km)
with lot's of archeological findings that the museum wants to show to
the
public. Our task in the project is to evaluate the possibilities of
using
IT for this. Our idea is that the visitors with a little computer in
their
hand walk along a marked woodland path while a GPS-coordinator locates
their position in realtion to the objects (graves, old roads, etc). They
are guided via the computer by text, pictures and animated sequences and
hopefully also sound.

---------------------------------------------------

I assume that by IT you mean Interactive Technology.  In Europe this
acronym is also used for Information Technology (which is a broader
subject). Nonetheless, your idea is quite interesting.

To my knowledge there is no system that currently exists that does what
you described.  Currently there are portable systems that will give
audio information about certain objects or locations.  The most common
system would be handheld recorders that plays back recorded information
in sequence.  If the visitor goes to location #1 and listens to the
information then proceeds to location #2, etc.

There are also systems that are based on limited range
tranmitter/receiver combination. Using a handheld receiver the visitor
can hear a continuous loop audio message when the receiver is within
range (e.g. 3 meters radius).

Using GPS (Global Postioning System) to select the information for the
particular site is a novel idea.  This certainly allows a lot of freedom
to the visitor.

(I hope you wanted a technical explantion)

The main limitations that I see comes from the accuracy and resolution
of the GPS.  Accuracy, having to do with the difference between the
coordinates of actual location and the reading on the GPS.  Resolution,
has to do with what is the the smallest difference in readings
detectable by the GPS.  That is, how far do you have to move before the
GPS displays a new reading.

Commercial GPS units (as opposed to Military) have a built-in inaccuracy
(courtesy of the US military).  However, the manufacturers have used
some clever ways to compensate and get better accuracy.  I don't know
exactly what the current accuracy is for commercial GPS units is but I
would guess that it is around 30 meters (100 feet).

Since most landmarks are located at a specific and known location it is
important that the GPS  unit is accurate particularly if there are
several sites within 30 meters of each other.  For example, let us say
that we have a site located on a grid at x=2, y=2. and your GPS says you
are at position x=3, y=2.  According to your INFO-System (let's call it
that for now) there is nothing located at x=3, y=2 so it has no
information for you.  No problem, we'll just make the INFO-System give
you information about the nearest site.  This works fine if there is a
definite "nearest" site.  What happens if there is another site at x=4,
y=2, which site is it?  Are you with me so far?  In other words,
according to your GPS you are located exactly between two sites.  Which
site's information does it give you?  This is where resolution comes
in.  If the GPS could give you finer detailed information such as your
position is x=3.9, y=2 then the INFO-System knows that you are slightly
closer to x=3, y=2.

So as far as the GPS is concerned, it will work if your sites are far
enough apart relative to the accuracy and resolution of the GPS used.

Now the question of storing and outputing "text, pictures and animated
sequences and
hopefully also sound".  This can all be done, it is simply a matter of
resources.  Money being one of the main restricting resource.  If cost
is not a consideration (yeh, right!) then the other limiting factors are
size, weight, battery life, etc.

As I see it, your proposed system is viable if the individual sites are
located far enough apart (for the GPS) and you don't mind spending a lot
of money for each portable unit.

-Mark-

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