Re: Garmin GPSmap 76C Review

From: Hans-Georg Michna (hans-georgNoEmailPlease_at_michna.com)
Date: 07/27/04 

Date: Tue, 27 Jul 2004 21:44:31 +0200

Jack,

I found the time to test the highway blockage question again and
conducted several more tests.

My results are that the function is not entirely reliable and
shows the occasional odd behavior, but it almost always works,
i.e. I am routed off the freeway and back on in typically 20 km.

I've had one or two cases in which this didn't quite work, i.e.
I was not routed off the freeway at the next opportunity, but
some distance later. But such exceptions, if rare, could be
explained by lack of alternative routes and exits or by some
weakness in the firmware algorithm, and a very useful function,
which almost always works, is still useful, particularly since
it is much better than all known alternatives.

I also saw some odd behavior when I wanted to change the route
back to the shortest way. There the device occasionally refused
and stuck stubbornly to the off-highway route, although I had
removed the Avoid Highway check mark and recalculated. The only
workaround for that situation was to choose a different
destination, calculate a useless route, then choose the original
destination and calculate the desired route again. When I did
this, the device forgot the old route and made an entirely new
one. This seems to be a defect, but it is inconsequential here
and not relevant to our tests. It only shows that the device is
not perfect.

But we have not found out why the Avoid Highway setting works so
very differently for you.

I would greatly appreciate if some other Garmin GPSMAP 60/76
C/CS users could test this too and report here which firmware
version, which maps, and which procedures you used.

The procedure to route around a freeway blockage is described on
http://www.michna.com/gps.htm#Garmin_GPSMAP_76C, second
subchapter, "Reroute Around Road Blockages".

You can test it easily in demo mode by placing the device on or
near a freeway with the following actions: PAGE to the satellite
page, MENU, Use With GPS Off, MENU, New Location, Use Map. Then
you select a far away destination and let the device drive along
the freeway in demo mode. Then follow the instructions mentioned
in the preceding paragraph.

The last time we discussed this here, there was a widely felt
regret that this function is not there. Now that it looks as if
it is there, I think we might as well learn more about it.

Hans-Georg 

-- 
No mail, please.

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