Laptop GPS World

I have been using Garmin Mobil PC for several weeks now and have not been able to figure out how to get it to provide headings in magnetic. I have looked for some means to input magnetic variation and have not been able to find any. My old Garmin handheld GPS II Pus allows magnetic variation to be entered (+ 14 where I am). Any suggestions or is true the only heading available? I am using datum WGS 84.
Thanks for your thoughts.

True north is likely the only option. I'm not in front of a laptop with Garmin Mobile PC on it at the moment, but I don't recall seeing an option to change this - and I'm sure if the option was there you would have found it already .

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Marvin Hlavac

Laptop GPS software reviews | Stores offering discounts to our members: Semsons & Co. Inc. and Deluo Electronics

Thanks for the reply.
It seems that it would be simple enough to accomplish in the software.
It is disconcerting that the Mobil PC never matches the compass heading (at least where I live).

No disrespect intended but it seems to me that you have it backwards. Correcting for Magnetic North is a hack that is only necessary if you are using a magnetic compass. And the correction is different, depending upon where you stand on the planet. Yes, the software could have a table containing all the possible correction factors but it's constantly changing and I'm not sure what purpose it would serve.

Maps are laid out using True North so with a GPS receiver no correction is necessary to get you going down the right road or keep you pointed in the exactly correct direction if navigating off road.

So you only need the correction when you are using a magnetic compass, not when you are using a GPS.

There is another significant difference between a GPS and a compass. A compass is designed to show direction based on a static reading. A GPS-based navigation device is designed to show direction based on the current direction of travel. There must be movement. It cannot compute direction from a static reading.

Having said that, I'm curious why you would like to have the ability to force the GPS to match your magnetic compass reading?

...ken...

I would like that ability simply because I am used to navigating with a magnetic compass. My old Garmin handheld gps has a variation input so that it can read magnetic. The electronic compass in my car has a variation input (so that it can read true). I have used various marine gps systems that all have the capacity to provide either true or magnetic readings.
I understand that it varies depending on where on the planet you are (hence "variation") and that it does change over time, but the change over time is small and most of my driving is in the same general location on the planet so that the correction factor does not need to be changed unless or until I take a trip.
While the software could contain a variation database, it only really needs to allow you to input the variation if you would so choose.

You have to understand that Garmin Mobile PC is a basic GPS mapping software derived from their standalone units. It was designed to be used by the general public, who I'd reckon to say most have no idea of the difference between true north, magnetic north, headings and bearings. They have a hard enough time looking out the window than navigating by the GPS alone.

The GPS II Plus receiver you're using is not designed for driving, so it has those features enabled. I can't recall a variation setting on any GPS road map product I've used (Mapopolis, S&T 2007, iGuidance 3)

Thanks for the input.
I hadn't really thought about it, but you are correct in that for navigating in the car where you are following roads, magnetic north is basically irrelevant.
Now I am curious and need to check the Honda navigation system in my wife's car (vintage 2000) to see if it allows a variation correction.

While the Garmin II Plus was not designed for driving, I have used it in my car for years and was used to having the heading in magnetic. I just sort of thought (assumed without critical thinking whether it was necessary) that the Mobile PC would be able to do the same thing.

DeLorme Street Atlas does allow switching between True North and Magnetic North. I might have seen this feature in at least one other laptop GPS navigation software program, but I just don't remember now which one it was.

Do you think there is any noticeable difference between True and Magnetic? I guess this would depend on your location. Perhaps if you live further north, than the difference could be noticeable(?).

__________________
Marvin Hlavac

Laptop GPS software reviews | Stores offering discounts to our members: Semsons & Co. Inc. and Deluo Electronics

Well, here in Toronto we have a variation of 11º W from true north. Up in Peterborough, it's 12º W. I don't think it matters much while driving.. but for flying, yes!

20 1/2º West Variation here in Sydney, Nova Scotia, 21º on Boularderie Island, increasing by 8' per year. That is noticable. We usually have the laptops's marine navigation software set to show magnetic as we use the large steering compass on the sailboat quite a bit and all of our backup paper charts have large compass roses with a magnetic inner ring printed on them. I'm used to Mobile PC displaying True for use in the car.

nRoute will let you decide which heading display you want. Its found from the "Edit" dropdown menu under "Preferences..." on the "Units" tab. It gives several choices, including Automatic Magnetic Varation, Grid, True, User Magnetic Varation and Cardinal Direction.

I can't find it in Mobile PC, probably for the reasons stated by others above, "KISS"

Attached Images

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