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Old 27-03-2011, 03:03   #436
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Re: Help / FAQ

Quote:
Originally Posted by GPS-Marco View Post
Hi ipnd, actually the link you suggest for deviation and declination says something slightly different. The first link (deviation) says:

"In nautical terminology deviation is the error caused by the metal parts of the ship, an error dependent on the magnetic heading (the angle the ship makes to magnetic north) whereas declination, also called variation, is the difference between true north and direction of the earth's magnetic field at that point without the ship. Of course variation in this sense is due to the location of the magnetic north pole as well as local geological conditions."

1) variation is a synonymous of declination (not deviation). This is not true for Italy, France and Germany (at least) where declination is never called variation.

2) declination is the difference between true and magnetic north "without the ship", i.e. it is not the total magnetic distorsion angle. Since it is independednt by the ship (and bu local distorsions), declination can be modelled at earth level (e.g. WMM).

Ciao, Marco.
A very old subject, but I can't resist to add something because this should be basic knowledge. From the thread it is clear that some don't/didn't understand exactly what the terms variation and deviation mean. In the end, Marco gives an answer based on an explanation in Wikipedia, which still raises my eye brows. I don't know why Wikipedia mentions declination as synonymus to variation. To me that is wrong. I'd like to stick to the definitions in the Bowditch, the US navigation bible (those agree to what I learned as a professional navigator outside the US):

1. Variation is the angle between the magnetic meridian and the true meridian at a given location. ...... The local variation and its small annual change are noted on the compass rose of all navigational charts. The true and magnetic headings of a ship differ by the local variation.

2. A ship's magnetic influence will generally cause the compass needle to deflect from the magnetic meridian. This angle of deflection is called deviation.

So:
Deviation is the difference between the compass heading (or compass north) and the magnetic heading (or magnetic north).
Variation is the difference between the magnetic heading (or magnetic north) and the true heading (or true north).
Compass Error is the sum of deviation and variation. This is the difference between compass heading (or compass north) and true heading (or true north); beware of the signs when adding).
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Old 27-03-2011, 03:17   #437
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Re: Help / FAQ

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Originally Posted by NAV View Post
I don't know why Wikipedia mentions declination as synonymus to variation. To me that is wrong. I'd like to stick to the definitions in the Bowditch, the US navigation bible
Continuing with Bowditch, 1977 Volume 1 p 198 line 12
Quote:
Variation (V,Var.), called declination (D) by magneticians,....
This could be the reason for the author of the Wikipedia piece.

Thomas
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Old 27-03-2011, 03:32   #438
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Re: Help / FAQ

You're right, Thomas. Also in my Bowditch 2002 declination is mentioned as synonymus to variation. I should have looked further .

Anyway, to my knowledge, in navigational practice it's never used that way, but only as a term in astronomical navigation.
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Old 27-03-2011, 09:50   #439
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Re: Help / FAQ

"Magnetician"that's cool.I'm going to check the Yellow pages .... but I agree with you ,NAV,as to colloquial usage,...Still, now it comes up,the magnetic centre is INSIDE the earth so a needle points up or down to it nearer the mag poles...so Declination does make sense... spherically speaking (as a Magnetician!)
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Old 27-03-2011, 10:14   #440
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Re: Help / FAQ

Up or down .. that's called magnetic inclination isn't it?
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Old 28-03-2011, 09:29   #441
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Re: Help / FAQ

I found some charts of Bahamas at:

4shared - My 4shared - shared folder - free file sharing and storage

The files have the extension snc. Are they compatible with OpenCPN? Thanks
Pete
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Old 30-03-2011, 03:02   #442
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Re: Help / FAQ

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Pete...

Thanks for the log info.

OpenCPN must use GRMN Host mode for route uploads to Garmin devices, otherwise you just get isolated waypoints, as you have discovered.

We had this problem earlier, but thought resolved. Could be a Win7 issue?

I will investigate with my old steam-powered GPS18 on XP. This may not be conclusive.....

Anyone else using GRMN host mode on Win7?

Thanks
Dave
Dave,
Do you know if this bug has been added to the list for the next version? If not, I would sure appreciate it. I'm running Version 2.4.324 Build 2011-03-24 Thanks
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Old 03-04-2011, 10:32   #443
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Re: Help / FAQ

I came across some Explorer charts of the Bahamas. They have extensions such as A01, A02, ... B01, B02, etc. OpenCPN can't read them. Is there a way to convert them to a form OpenCPN can read? Thanks
Pete
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Old 03-04-2011, 11:47   #444
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Re: Help / FAQ

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Originally Posted by prroots View Post
I came across some Explorer charts of the Bahamas. They have extensions such as A01, A02, ... B01, B02, etc. OpenCPN can't read them. Is there a way to convert them to a form OpenCPN can read? Thanks
Pete
These might be maptech charts.Rename a copy as a .pcx and open it in an image viewer ... IF I am right,Yes,you can use em fine BUT it's a real process you can go from there in Map_Cal2...or(sigh)
...I have a system for XP and map2kap ....Download the trial OziNavigator and get the maptechpcx plugin...then a trial version of Snagit to grab the screen as tif.Then to Map2kap thread here map2kap - OziExplorer to OpenCPN where I started converting a ton of these(200 or more)...PM me if you think you are up to it and I'll help get you going but you may have another way through that works as well.
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Old 03-04-2011, 13:23   #445
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Re: Help / FAQ

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These might be maptech charts.Rename a copy as a .pcx and open it in an image viewer ... IF I am right,Yes,you can use em fine BUT it's a real process you can go from there in Map_Cal2...or(sigh)
...I have a system for XP and map2kap ....Download the trial OziNavigator and get the maptechpcx plugin...then a trial version of Snagit to grab the screen as tif.Then to Map2kap thread here map2kap - OziExplorer to OpenCPN where I started converting a ton of these(200 or more)...PM me if you think you are up to it and I'll help get you going but you may have another way through that works as well.
Thanks. Given that I'm running under Windows 7, what do you suggest? BTW, I was able to view it as image after changing extension to pcx.
Pete
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Old 03-04-2011, 14:58   #446
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Re: Help / FAQ

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Thanks. Given that I'm running under Windows 7, what do you suggest? BTW, I was able to view it as image after changing extension to pcx.
Pete
Well,I'm in XP but Win7 should work the same.
...the Hurdle is,as you know,these are tiles.The biggest time is going to be capturing em as full size and pairing them with the calibration file ozi provides.Downld the above two apps is my suggestion.You will,with ozi,see the charts in full IF you hunt down and include the pcx plugin.so do that first

I will post the recipe on the map2kap thread....
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Old 08-04-2011, 10:11   #447
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Re: Help / FAQ

I am a long-time user of OpenCPN. It is great. Thanks for all the hard work.

I had been running the 64 bit Ubuntu 2.1 version without problems for quite a while. The other day I installed 2.3.1 and it boots to the menu bar and a grey map field causes my computer to freeze. The cursor can be moved a bit but clicking doesn't seem to work and I end up turning off the computer to reboot. I also uninstalled and tried the beta with the same result.

Todd Shuster
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Old 08-04-2011, 11:01   #448
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Re: Help / FAQ

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Originally Posted by Gato Verde View Post
I am a long-time user of OpenCPN. It is great. Thanks for all the hard work.

I had been running the 64 bit Ubuntu 2.1 version without problems for quite a while. The other day I installed 2.3.1 and it boots to the menu bar and a grey map field causes my computer to freeze. The cursor can be moved a bit but clicking doesn't seem to work and I end up turning off the computer to reboot. I also uninstalled and tried the beta with the same result.

Todd Shuster
Gato Verde

Which version of Ubuntu are you on?
Can we have a look at your OpenCPN log, which is a file called opencpn.log in your home directory?
It's enough to see he entries from your last session.

Thomas
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Old 08-04-2011, 14:18   #449
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Re: Help / FAQ

Thomas,

I'm running 64 bit Ubuntu 10.10.

Here is the log from my last attempt at running:


09:14:00 AM: 2011-04-08
09:14:00 AM: -------Starting opencpn-------
09:14:00 AM: Version 2.3.1 Build 2010-12-28
09:14:00 AM: SData_Locn is /usr/local/share/opencpn/
09:14:00 AM: Using existing Config_File: /home/todd/.opencpn/opencpn.conf
09:14:00 AM: Setting Viewpoint Lat/Lon 48.5915, -122.794
09:14:00 AM: Setting Ownship Lat/Lon 48.7225, -122.513
09:14:00 AM: System default Language: en_US
09:14:00 AM: Opencpn language set to: en_US
09:14:00 AM: looking for catalog 'opencpn' in path '/usr/local/share/locale/en_US.UTF-8/LC_MESSAGES:/usr/share/locale/en_US.UTF-8/LC_MESSAGES:/usr/share/locale/:/usr/share/locale/en_US.UTF-8:/usr/local/share/locale/en_US/LC_MESSAGES:
/usr/share/locale/en_US/LC_MESSAGES:
/usr/share/locale/:/usr/share/locale/en_US:/usr/local/share/locale/en/LC_MESSAGES:
/usr/share/locale/en/LC_MESSAGES:
/usr/share/locale/:/usr/share/locale/en'.
09:14:00 AM: catalog file for domain 'opencpn' not found.
09:14:03 AM: Using s57data in /usr/local/share/opencpn/s57data
09:14:03 AM: Using Tide/Current data from: /usr/local/share/opencpn/tcdata/
09:14:03 AM: Setting Viewpoint Lat/Lon 48.5915, -122.794
09:14:03 AM: Setting Ownship Lat/Lon 48.7225, -122.513
09:14:03 AM: NMEA Data Source is....Serial:/dev/ttyUSB0
09:14:03 AM: AIS Data Source is....None
09:14:03 AM: Using WVSChart datafile: /usr/local/share/opencpn/wvsdata/wvs43.dat
09:14:03 AM: NMEA AutoPilot Port is....None
09:14:03 AM: PlugInManager searching for PlugIns in location /usr/local/share/opencpn/plugins
09:14:03 AM: PlugInManager: Loading PlugIn: /usr/local/share/opencpn/plugins/libgrib_pi.so
09:14:03 AM: PlugInManager: Loading PlugIn: /usr/local/share/opencpn/plugins/libdashboard_pi.so
09:14:03 AM: Loading chart db version: V016
09:14:03 AM: Chartdb: Chart directory list follows
09:14:03 AM: Chart directory #0: /home/todd/Desktop/nav programs & data/Charts/BSB_ROOT
09:14:03 AM: Chart directory #1: /home/todd/Desktop/nav programs & data/Charts/ENC_ROOT

Thanks for your prompt reply!

Todd
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Old 09-04-2011, 00:46   #450
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Re: Help / FAQ

Todd

Provided that the listed chart directories #1 & #2 still exists, there may be something funny with the chart data base. Normally OpenCPN should go ahead and search the directories for chart files.

Try this: exit OpenCPN and execute.
Code:
mv /home/todd/.opencpn/chartlist.dat /home/todd/.opencpn/chartlist.dat.old
When you restart, OpenCPN will ask for chart directories.
If this solves the problem the file "chartlist.dat.old" would be of interest for the developers.

Thomas
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