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Re: VitoNavigator II .SMT tracks?

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Re: VitoNavigator II .SMT tracks?

Ron Parker-2
At 01:44 PM 6/8/2005, Robert Lipe wrote:
> > If I multiply all values by 57.295, I get latitude/longitudes that are very
> > close to actual coordinates.
>
>Offhand, I really can't think of anything I've seen that uses a scaling
>like that and can't come up with any logic behind that number.

180/pi is approximately 57.295779513082320876798154814105.  That'd mean
that the values in the file are in radians, presumably.


--
Ron Parker



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RE: VitoNavigator II .SMT tracks?

Tasse, Etienne
R.L> Offhand, I really can't think of anything I've seen that uses a scaling
R.L> like that and can't come up with any logic behind that number.  I won't
R.L> say that multiplying by 57.295 isn't the right approach, but let me
R.L> offer a general word of caution about "magic" conversions like this.


R.P>180/pi is approximately 57.295779513082320876798154814105.  That'd mean
R.P>that the values in the file are in radians, presumably.

 lat =  ((*buf)   * 180) / M_PI;
 lon =  ((*buf+8) * 180) / M_PI;
 printf( "%ld,%ld\n",lat,lon);

Pi has always been a magic number IMHO  :-)

Next hurdle, the speed / timestamp values.

I've been Googling and searching forums all over for information about
VITO's SMT format.
This is the first real breakthru I've seen

Thanks to Rob and Ron for the insight.  Now I need to get off my butt and
code
the filter functions for GPSbabel.


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RE: VitoNavigator II .SMT tracks?

Ron Parker-2
At 03:19 PM 6/13/2005, Tasse, Etienne wrote:

>R.L> Offhand, I really can't think of anything I've seen that uses a scaling
>R.L> like that and can't come up with any logic behind that number.  I won't
>R.L> say that multiplying by 57.295 isn't the right approach, but let me
>R.L> offer a general word of caution about "magic" conversions like this.
>
>
>R.P>180/pi is approximately 57.295779513082320876798154814105.  That'd mean
>R.P>that the values in the file are in radians, presumably.
>
>  lat =  ((*buf)   * 180) / M_PI;
>  lon =  ((*buf+8) * 180) / M_PI;
>  printf( "%ld,%ld\n",lat,lon);
>
>Pi has always been a magic number IMHO  :-)
>
>Next hurdle, the speed / timestamp values.

Could you send me (off list) one or two files in this format along with what
you think should be in them?  I've got a little experience with reverse-
engineering binary formats, though of course I can't guarantee anything.

Two things to keep in mind: First, the header (that first 24-byte chunk)
might contain magic numbers or other settings that you want to check before
jumping into reading the rest of the data and assuming it's a known format,
and second, you want to make sure your code will work on big-endian and
little-endian hardware (which means using the various functions provided in
util.c for the purpose.)



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