World Magnetic Model Plugin

[nohal]

Navigators...
while playing with stuff I hacked together a very small plugin implementing the World Magnetic Model published by NOAA into OpenCPN.
The plugin requires OpenCPN 2.4.324 or later to work correctly.
In the preferences you can tailor the amount of displayed information to your liking - from one-line declination display at boat's location to all the components that please the freaky magnetician.
Useful? And yes, I know I should have done it as an instrument in the dashboard plugin

Linux version:
https://github.com/downloads/nohal/OpenCPN/libwmm_pi.so
place the downloaded file into your plugin folder - most likely /usr/local/share/opencpn/plugins

Windows version:
https://github.com/downloads/nohal/OpenCPN/wmm_pi.dll
place the downloaded file into your plugin folder

Source lives at https://github.com/nohal/OpenCPN/tre...plugins/wmm_pi

Enjoy

Pavel

[NAV]

What a coincidence. I just finished changing the text about magnetic variation in the manual a bit (seconds ago).

I'll try you're plugin right away.

Edit:
It's showing the variation and the annual change at the cursor. In the boat field, I don't see anything, probably because no GPS is connected.

The variation map (as shown in your mail) seems not to be part of the plugin. I guess it should be downloaded and georeferenced separately before it shows in openCPN.

Switching to extended mode crashes openCPN on my system (first time I experience this with any plugin). Seems to be at any first preference change, not always.

Advice: for navigational purposes (and that's what openCPN is about) the term "variation" should be used in case of the term "declination".

[NAV]

Originally Posted by NAV

It's showing the variation and the annual change at the cursor.

I was wrong about the annual change. It only shows the variation, both in decimal degrees and in degrees and minutes. However, the annual change in variation is also availbale in the model, as stated on the NOAA site.

It is necessary to show the latest date that the data in the model is still valid (or the year for which the data is valid AND the annual change)! Also the units used for presentation of the data should be shown (nT -nanoTesla, deg - degrees, min - minutes per year).

Anyway, a very handy tool.


Crashing seems to happen whenever a presentation change is made without switching WMM off first, using the icon.

[nohal]

NAV,
the chart is not part of the plugin, it is georeferenced and available for download from opencpn.org for quite some time.
Regarding the terminology I stayed with all terms magnetic to keep it consistent. I'm personally not that allergic to declination as my book said it's a synonym to variation when I last read it
Crash reproduced - can happen only when you change prefs before displaying the plugin window for the first time - fixed. Will release new version when time comes.

Thanks

Pavel

[cagney]

Nohal

Nice plugin!
I am allergic to "landlubber" terminology.
Let a future astro-navigation plugin use "declination", and please use "variation" which is the traditional nautical term.

Yeah, I had the crash as well.

I would like to compile he plugin for my 64 bit Ubuntu, but get a bit confused as " git clone git://github.com/nohal/OpenCPN.git " don't include this plugin. Is there an other git command I should use?

Thomas

[nohal]

Thomas,
you guys convinced me, going to burn declination
The plugin lives in a branch named wmm
You can even "mix" it with the sourceforge tree - just go to your source dir and do

git remote add nohal  git://github.com/nohal/OpenCPN.git
git fetch nohal
git checkout nohal/wmm

git branch -a

gives you the list of all the branches available. Without the -a switch just local branches are displayed

Pavel

[manimaul]

Pavel,

Awesome!

[cagney]

Thanks Pavel.
No 64 bit surprises. Compiled OK.
Thomas

[Gilletarom]

hello,

First use ----> crash when I change the "Prferences". Exactly when I click on "Ok" for validate my new choice.

Best regards

Gilletarom

[nohal]

Gilletarom,
thanks, already fixed, will be in the next release.

Pavel

[Gilletarom]

Hello,

Seems work fine when I connect the GPS.

Problem :

The window of this plugin, is above all the windows.

See attach file

Gilletarom.

[nohal]

Version 0.2 is out, considered stable
Changes:

• Fixed crash in settings dialog
• Changed window behavior from being globally on top to be just on top of the application window
• Night mode support
• Units shown (if you don't like it, make your custom .mo file)
• Model expiration note and instructions added in plugin description
• Plugin now clearly shows it's hate to the magnetician community by strictly using the nautical term Magnetic Variation instead of Geomagnetic Declination The magneticians can also make their own .mo to revert it as a revenge.

Download for Windows and Linux from https://github.com/nohal/OpenCPN/downloads
If anybody makes a Mac version, send it to me to make it available as well - there are still no apples on my table.

If someone wants to translate the plugin, the POT can be downloaded from https://github.com/nohal/OpenCPN/blo...i.pot?raw=true
Just send me back the .po and I will make the localization available for download.

Enjoy

Pavel

[Gilletarom]

Hello,

I'll do the translation in French.

Gilletarom

[Gilletarom]

Hello Pavel,

In the .pot I read this item :

World Magnetic Model PlugIn for OpenCPN\n
Implements the NOAA World Magnetic Model\n
More information: http://www.ngdc.noaa.gov/geomag/WMM/\n
The bundled WMM2010 model expires on December 31, 2014.\n
After then, if new version of the plugin will not be released\n
in time, get a new WMM.COF from NOAA and place it to the\n
location you can find in the OpenCPN logfile.

When you say logfile, is it the .log or the .ini ?

Gilletarom

[Gilletarom]

Hello,

No, not stable because the window is above all other windows and this is unpleasant

What are the units for F, H, X, Y, Z, Incl, Decl ? Is it possible to write these units in each line ?

It would be nice if there was a button on the "Boat" of the extended display. This button would go to shows simplified and vice-versa.

Gilletarom.