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Old 07-09-2013, 08:29   #1
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Please Help: Magnetic Course Display in OpenCPN

I am a new member of this forum and I new user of OpenCPN. I have been a sailor for more than 35 years and done charting and routing on numerous software programs and paper charts before these wonderful things existed. And if this is an overly used or abused subject matter, I apologize in advance for bringing up again. I cannot understand why a program of this power and sophistication does not display courses in either True or Magnetic format at the user's choice. I have done searches on this subject matter in this forum and on the Internet and I am now at the point of going in circles. I hope this is not because I am getting too old and no longer understand proper searching techniques. Please, is there a way of displaying the courses created in OpenCPN in Magnetic as well as in True.

I thank you for any help you can give me.
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Old 07-09-2013, 09:35   #2
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Re: Please Help: Magnetic Course Display in OpenCPN

It is currently not possible to display magnetic bearings or courses.
Basic Features | Official OpenCPN Homepage

It is however a long standing feature request from some users.
See here: OpenCPN::Tracker All Projects: Tasklist
and here: OpenCPN::Tracker All Projects: Tasklist

The Magnetic variation is always available through the World Magnetic Model plugin. Download here: PlugIns | Official OpenCPN Homepage

Thomas
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Old 07-09-2013, 10:39   #3
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Re: Please Help: Magnetic Course Display in OpenCPN

Quote:
Originally Posted by cagney View Post
It is currently not possible to display magnetic bearings or courses.
Basic Features | Official OpenCPN Homepage

It is however a long standing feature request from some users.
See here: OpenCPN::Tracker All Projects: Tasklist
and here: OpenCPN::Tracker All Projects: Tasklist

The Magnetic variation is always available through the World Magnetic Model plugin. Download here: PlugIns | Official OpenCPN Homepage

Thomas
G'Day Thomas,

Why, if it is a long standing feature request, and likely not so hard to code in, has it not been addressed?

I have been so very impressed with the development of this program, and am a happy user, but can't help wondering about this lacking. I don't want to be engaged in yet another "you need to use true bearings because..." argument, but lots of us prefer to do our plotting using magnetic bearings. I actually do know how to apply the corrections, and have successfully done so for years, but it is another potential source of piloting error, one that could be avoided.

So, please add my name (again) to the list of supplicants for this improvement to a great program.

Cheers,

Jim
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Old 07-09-2013, 11:01   #4
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Re: Please Help: Magnetic Course Display in OpenCPN

Why would you need magnetic bearings to plot your course when your GPS and Plotter/charts work in tandem with True?
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Old 07-09-2013, 12:34   #5
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Re: Please Help: Magnetic Course Display in OpenCPN

Quote:
Originally Posted by John A View Post
Why would you need magnetic bearings to plot your course when your GPS and Plotter/charts work in tandem with True?
John, please re-read my post. I do not want to spin my wheels arguing about this subject. Please let me express my desire for a small change in OCPN without moral lectures. I have developed my piloting and navigation practices over more than 40 years and nearly 150,000 miles of sailing. I don't care if you or others think they are lacking in purity for I know that they work for me.

Cheers,

Jim
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Old 07-09-2013, 13:26   #6
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Re: Please Help: Magnetic Course Display in OpenCPN

This subject may be a weakness in my navigation knowledge but my understanding is that I chart a TRUE course on the chart and then apply the local variation to set a MAGNETIC course across the planet.

As we all know variation has a huge...well...variation all over the world and is constantly changing all be it very slowly.

The jinggle I repeat to myself is " Variation east compass is least, variation west compass is best".....I get that!
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Old 07-09-2013, 14:04   #7
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Re: Please Help: Magnetic Course Display in OpenCPN

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Originally Posted by Jim Cate View Post
I do not want to spin my wheels arguing about this subject.

Cheers,

Jim
Jim, clearly understood and respected. Just somebody has to implement it...

In the meantime having the WMM plug-in installed hovering with the mouse over the site (or point of the track) you want ot analize the WMM will show the declination for this point.
It's a work-around, yes.
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Old 08-09-2013, 04:03   #8
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Re: Please Help: Magnetic Course Display in OpenCPN

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Originally Posted by Jim Cate View Post
G'Day Thomas,

Why, if it is a long standing feature request, and likely not so hard to code in, has it not been addressed?

I have been so very impressed with the development of this program, and am a happy user, but can't help wondering about this lacking. I don't want to be engaged in yet another "you need to use true bearings because..." argument, but lots of us prefer to do our plotting using magnetic bearings. I actually do know how to apply the corrections, and have successfully done so for years, but it is another potential source of piloting error, one that could be avoided.

So, please add my name (again) to the list of supplicants for this improvement to a great program.

Cheers,

Jim
G'Day Jim,

This boils down to what "bdbcat" use to call "limited developers bandwidth". Simply not enough with people actually coding.
Have you ever had a look at the trackers feature requests? There are literary hundreds of them!

You could also say, that if any of the developers had been using magnetic courses and bearings, it would have been fixed by now.

I agree that this request should be implemented. It's really an established alternative to handle your navigation.

Please add your votes to the feature requests on the tracker and keep this thread visible, and eventually, I'm sure, the feature will be implemented.

Thomas
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Old 08-09-2013, 07:18   #9
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Re: Please Help: Magnetic Course Display in OpenCPN

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Originally Posted by cagney View Post
G'Day Jim,

This boils down to what "bdbcat" use to call "limited developers bandwidth". Simply not enough with people actually coding.
Have you ever had a look at the trackers feature requests? There are literary hundreds of them!

You could also say, that if any of the developers had been using magnetic courses and bearings, it would have been fixed by now.

I agree that this request should be implemented. It's really an established alternative to handle your navigation.

Please add your votes to the feature requests on the tracker and keep this thread visible, and eventually, I'm sure, the feature will be implemented.

Thomas
Thomas, thanks for the non-judgmental reply! I do understand about limited resources and don't want to come across as demanding... more curious as to the reason that this small feature has not been implemented long ago. And I think that your idea about what the developers use personally is a likely candidate.

If my programming skills were not so desperately out of date (FORTRAN, for gosh sake!) I'd have a go at it myself, but that seems futile in the real world.

And for JohnA: sorry if I seemed snippy in my response. In a previous thread related to this subject I was subjected to a lot of criticism for my practice of using magnetic bearings and I became a bit sensitized. FWIW, my navigation/piloting ideas were developed long before GPS was on the scene, and we relied upon magnetic compasses and sextants entirely. The charts of the day had both true and magnetic roses printed on them, and it was easier to just use magnetic bearings. I still often use handbearing compasses as well as the ships compass in daily exercises at sea, and would find the inclusion of magnetic bearings in OCPN useful.

Cheers,

Jim
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Old 08-09-2013, 08:46   #10
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Re: Please Help: Magnetic Course Display in OpenCPN

Jim Cate,
That's OK, some of my remarks are blunt to a fault and I' trying to correct this. The days of Fortran, PL1, Cobol, and Assembler those were the says.
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Old 08-09-2013, 20:57   #11
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Re: Please Help: Magnetic Course Display in OpenCPN

Jim...

It its not too much trouble, could you post a few screen shots of OpenCPN to show exactly where you would like to see Mag Heading instead of True Course?

Regarding resources,
Probability of implementation ~= n-requesters/m-difficulty.....

And, the surmise is correct. I use True courses generally

Thanks
Dave
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Old 09-09-2013, 12:39   #12
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Re: Please Help: Magnetic Course Display in OpenCPN

Quote:
Originally Posted by bdbcat View Post
Jim...

It its not too much trouble, could you post a few screen shots of OpenCPN to show exactly where you would like to see Mag Heading instead of True Course?

Regarding resources,
Probability of implementation ~= n-requesters/m-difficulty.....

And, the surmise is correct. I use True courses generally

Thanks
Dave
G'Day Dave, and thanks for the reply.

First, I must blushingly admit that I don't know how to post a screen shot, so for now that's not a player. Second, I'm about 8000 miles from my boat where I could perhaps generate some useful screen situations for demonstration purposes, and I won't be back in a useful time scale.

So, I'll try to describe where I think it would be specifically useful. Note: my experience with other plotting programs is limited to C-Maps, Max Sea and Nobletech (all old versions from the "distant past"), and in the latter two one simply toggled an option somewhere in the setup routines and all bearing references would go from true to mag and back. This is generally what I had envisioned for OCPN... but that vision is from a naive point of view coding wise.

Anyhow, here is a partial list of places where I would like to see magnetic bearings:
bearing to cursor
bearing in track, route and waypoint properties
bearing in measure mode
route and track bearings when "hovering" on the track/route
course over ground
AIS reports

There are likely some that I didn't think of, but that's the general idea that I had.

Thanks for the interest in what may be a rather idiosyncratic desire.

Cheers,

Jim
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Old 09-09-2013, 12:57   #13
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Re: Please Help: Magnetic Course Display in OpenCPN

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If my programming skills were not so desperately out of date (FORTRAN, for gosh sake!) I'd have a go at it myself
Dimensioned arrays, specified input & output devices, a real lean machine code after the compiler, yea, I remember that one.
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Old 09-09-2013, 13:53   #14
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I also would really like to see magnetic degrees as an option in how to display bearings. A button in the top toolbar that toggled between "M" and "T" would be perfect. Other than this big missing feature, I think OpenCPN is darn near perfect.
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Old 09-09-2013, 14:17   #15
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Re: Please Help: Magnetic Course Display in OpenCPN

Dave,

I agree with Jim that being able to navigate using magnetic values is a very useful feature.

If one should find them self doing a coastal passage with a electronic chart that is not using the WGS84 datum, it would still be possible to use the chart. By using magnetic bearings and depths it would be possible drop waypoints showing the boat's track relative to the shoreline. And, of course, it would be helpful in determining the compass course to be steered when one doesn't have a plotter at the helm.

BTW, I just upgraded to 3.2.2 and was very disappointed to discover that the range ring feature has been removed. I don't really understand why a common feature like that would ever be removed. Please put it back in.

Thanks,

Paul
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