[Loadstone] Approaching Question

Shawn Kirkpatrick shawn at odyssey.cm.nu
Sun Nov 12 01:59:49 GMT 2006


The max search radius has nothing to do with the point announcing. Having 
that set to 2000 (it's in kilometers) is probably pretty high unless you 
have 
very few points in your area. If you get a search that goes off the end of 
your database it may take a very long time to complete.
Point announcing is controled by the max approach distance (in meters) and 
min approach time (in seconds) settings. The system mainly uses the min 
approach time setting. The max approach distance is used as a fall back, 
mainly for very low speeds where the time calculations wouldn't work 
propperly. The distance method would appear to be a good choice until it's 
used in a vehicle. If you're on a bus going 60 miles per hour you're moving 
at around 30 meters per second (a very rough calculation). So if you have 
your max approach distance set to 50 meters that means you have just over 1 
second of warning before you pass your point. That's not nearly enough if 
you're trying to hit a bus stop. This is why the time method is used. This 
takes your speed in to account and tends to work much better. This also 
means that you have to set the min approach time to something reasonable. If 
it's too high then you'll get announcements too early and too low you won't 
have enough time to react. I find that 30 seconds works well but you can go 
as low as 10 seconds. Another thing that will effect this is the point's 
accuracy. If you enter a point using the gps for its position then this 
probably won't be a problem. If you enter a point manually or it's a point 
in the database that's been calculated then the accuracy may be within 100 
meters or so. In that case that point may be announced sooner then you'd 
expect.

On Sat, 11 Nov 2006, Michael O. Hanson wrote:

> I have the max approach distance set at 50 and the max search radius set to
> 2,000.  I installed version 0.65 before the event described below happened.
>
> I was on a bus yesterday.  I got to about 1,000 yards of a point of
> interest.  Loadstone informed me I was approaching that point.  How do I get
> Loadstone to use the approach distance I put in?
>
> Thank You,
>
>
> Mike Hanson
>
>
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