balloonatic
Posts: 18
Joined: Mon Aug 16, 2004 7:17 pm
Location: Canada

Magnetic Variation and Compact Framework

Tue Aug 31, 2004 10:40 pm

The online docs. for GPSTools state that...

"The RMC event is not supported by the Compact Framework version."

Why is this?
Is there any other way I can get Magnetic Variation?

I know this information is available in the following sentences:
-RMA
-RMC
-VTG
Has anyone pulled this info. before?

I would like to be able to display both Magnetic and Ture headings in my application.

Thanks...

See Yah

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johan
GpsGate
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Location: Sweden
Contact: Website

RE: Magnetic Variation and Compact Framework

Wed Sep 01, 2004 10:12 am

Catch the GpsTools.NmeaParser.OnMovement() event or call GpsTools.NmeaParser.GetMovement(). There you got properties for magnetic variation and true heading.

Read more about it in the reference manual.

Regards,
Johan

Franson Support

balloonatic
Posts: 18
Joined: Mon Aug 16, 2004 7:17 pm
Location: Canada

RE: Magnetic Variation and Compact Framework

Fri Sep 03, 2004 2:35 am

I use these two lines (one right after the other) and the heading works but the magnetic variation does not.

drNewRow.Item("db_heading") = objMove.Heading
drNewRow.Item("db_magnetic_variation") = objMove.MagneticVariation

I've examined the RMC sentence and I'm not getting magnetic variation?

Looks like the GPS is not sending the data to the objMove object???
Any ideas why this would happen?


See Yah

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johan
GpsGate
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Location: Sweden
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RE: Magnetic Variation and Compact Framework

Fri Sep 03, 2004 1:39 pm

No I have no idea, if you post a short dump of your NMEA data I might be able to say something.

Regards,
Johan

Franson Support

Duncan
Posts: 1
Joined: Tue Sep 07, 2004 4:53 pm
Location: South Africa

RE: Magnetic Variation and Compact Framework

Tue Sep 07, 2004 5:15 pm

There are many GPS devices out there that do not support Mag Var. If you see that your NMEA string does not return any values, then you can be sure that this feature is not supported on your GPS. Typically I have seen that the SiRF chipest in most BT and CF type devices does not support mag var. These devices are typically designed for in-vehicle navigation where mag var is normally not required.

If you capture a few lines of NMEA code with a Garmin type device, you will see the difference straight away.

Normally, as soon as your device receives a valid 2D or 3D fix, then there will be a value for mag var and W or E.

I recommend that you question the manufacture about this. You will most probably find that you are going to have to buy yourself a different GPS that supports this function.

It might be interesting to compile a list of known devices so that if your application requires this feature, then you will at least know what devices not to buy.

Duncan

balloonatic
Posts: 18
Joined: Mon Aug 16, 2004 7:17 pm
Location: Canada

RE: Magnetic Variation and Compact Framework

Wed Sep 08, 2004 10:42 pm

Duncan,

I think you've got it!

I checked the RMC senetence and the GPS is not providing the data.
It's a Holux GM-270 (non-ultra) CF Card GPS.

I've checked the manuf. web site and there is no mention that the MagVar is not generated?? It does use a SiRF chipset though!

I just emailed the manuf. about this. I'll report back to this forum when I hear back from Holux.

I'll try connecting my Vista to the iPAQ and see what happens.

Thanks for the info!

Steve

See Yah

balloonatic
Posts: 18
Joined: Mon Aug 16, 2004 7:17 pm
Location: Canada

RE: Magnetic Variation and Compact Framework

Tue Sep 14, 2004 11:42 pm

I connected my Vista to the PDA last night and I was getting Magnetic Variation just fine.

This a problem (oversight) with the SiRF chipset.

Case Closed!
Thanks for the help...

Steve

See Yah

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