OpenCPN General

[Viking Sailor]

Looks great!

However, this should be part of route planning inside of OpenCPN. Where you would define a route, add waypoints, and select either great circle or rhumb line between sets of waypoints. For great circle routes the current course needs to be recomputed and displayed.

[cagney]

Here is the latest version of the Great-Circle tool that also is able to calculate composite routes. Note that OpenCPN Version 1.3.5 Build 1210 is not showing correct distance for composite sailing.
I have tried to cover all cases I was able to imagine.
If you want a composite route, it is best to first display the pure great-circle route, it will the be obvious if composite sailing is possible.

I have not written this script because I think that great circles are very useful or important for cruising, but it is interesting to know about great-circles and it was a fun challenge.

In high latitude passage making, where great-circles are much shorter than rhumb lines, I think weather considerations is the most important factor. My plan would be to stay in the Chen-Chesneau Zone A if at all possible ( Ma-Li Chen and Lee S. Chesneau: Heavy Weather Avoidance and Route Design, Concepts and Application of the 500Mb Charts).

I don't think it is of any great importance to integrate great-circle routes into OpenCPN. For the very odd time, when it is actually needed, it is not unreasonable to use an external script.
I hope that OpenCPN in the future will not become a bloated slow Swiss Army Knife of Navigation , but instead stays a sleek fast tool that handles the most important tasks in navigation while en route, really well.
</END_RANT>

Thomas

[Viking Sailor]

Thomas,

OpenCPN already has and uses great circle calculations. What it lacks is rhumb line calculations. Rhumb line routes are what makes Mercator projections useful.

Paul

[sf-robert]

I am running OpenCPN Version 1.3.5 Build 1122 and have installed charts as follows:

US5CA13M, US5CA41M US5CA42M, US5CA43M, US5CA44M, US5CA45M, US5CA16M, 18680, 18685, 18686, US5CA12M, US5CA21M, US5CA31M

I just discovered that when right clicking on a current or tide station that I get a pop-up box showing the details for that day for that station. I've discovered that one can click next or previous to scroll from day to day. I've also seen that I can set a new system date on my xp-pro system and that date shows up.

I'm just wondering - where is that data coming from and how much of it is there? One person wrote that it is xtides, which is interesting, but I was wondering where the data is stored? In the charts listed above? Part of the openCPN install? I don't think it requires live internet downloads, as I tried it with my wifi turned off and still got data. Is it a strictly mathematical calculation?

I understand as "predictions" that reality may be somewhat different than what shows, but it's a great planning tool.

Lastly, I understand the difference between raster and vector graphics, but of the charts above - which are which. I'm guessing that the numbered charts are raster while the US5... charts are vectory.

It's just a lot of new information for me, and I appreciate anyone's patient explaination.

Robert

[cagney]

Just a note about running my Ruby programs on windows.
When you install ruby you can choose to include the text editor Scite, this is a good idea.(much more advanced than "Text Editor")
The programs I have uploaded from Linux have LF = line feed as line endings. Windows use CR + LF (CR = carriage return).
Right Click on the downloaded program and choose edit.
This brings up the program in Scite. Go to Options ==> Line End Characters and mark CR+LF and save.
You now have to use cmd.exe also called the Dos-window to run the program. Once it looks similar to this

>F:\Thomas\Mine\gc_0.2.1.rb

hit enter and follow the instructions on the screen for how to enter the options.
Latest version with a minor bug fix included.

Thomas

[crienoloog]

Again sorry to interrupt and maybe duplicate question [couldn't find it here]...
I have Ubuntu 9.10 and installed the Linux version 1.3.4 In the beginning it worked fine although installing was weird and couldn't find the program start button [ later in usr/local/bin ]. Then all of the sudden loading large amount of maps would crash the program and now I can't even start it anymore... reinstalled without success.
Also have a problem with tracking GPS in USB but that is probably my Garmin Quest problem. Computer see the GPS in USB but not in GPSBabel or any other GPS program.
Thanks for your help.
With kind regards,
Eric

[cagney]

If you delete the hidden directory .opencpn in your home directory, and then reinstall you should get going. Also check opencpn.log in your home directory for possible error messages. To start opencpn just write "opencpn" on the command line and hit enter, but there should be a button somewhere in your menu system as well.

Thomas

[crienoloog]

Originally Posted by cagney

If you delete the hidden directory .opencpn in your home directory, and then reinstall you should get going. Also check opencpn.log in your home directory for possible error messages. To start opencpn just write "opencpn" on the command line and hit enter, but there should be a button somewhere in your menu system as well.

Thomas

Uhhhh.... in Linux?

[cagney]

Yeah! Just kidding. No need to reinstall, just restart. No need to delete the whole directory either, but as you just started, you don't have much to loose.
Thomas

[idpnd]

Originally Posted by crienoloog

Also have a problem with tracking GPS in USB but that is probably my Garmin Quest problem. Computer see the GPS in USB but not in GPSBabel or any other GPS program.

Take a look at ubuntu forums..

[cagney]

Originally Posted by Viking Sailor

Thomas,

OpenCPN already has and uses great circle calculations. What it lacks is rhumb line calculations. Rhumb line routes are what makes Mercator projections useful.

Paul

Paul
You were right, until the latest beta. Now OpenCPN has Mercator Sailing but no built in great circle calculation, which in my view is an improvement as OpenCPN only uses Mercator charts.
It all became a bit ridiculous when the measurement tool showed similar distance on a straight line as a great-circle route distance.

Thomas

[brettnkay]

Well, the risk of getting an earful, I'd like to back the discussion up a few meters....

Installed OpenCPN (windows Vista), downloaded numerous free ENC charts from NOAA, pointed the Charts directory on the Tools menu to the folder, and clicked "Add Selection" to .txt, .000, and even folders. But, I still get the message "No Charts Available" and just a black screen.

Any suggestions? Sorry for the very basic question when everyone else is talking about the subtleties of AIS, raster, etc I can't even get a simple chart to display on the screen.

[sinbad7]

brettnkay..

Did you highlight each directory containing valid maps before adding them?
If you don't have cm93 maps installed,perhaps you are starting up in a geo location not covered by your installed maps? Try panning to a location you KNOW is covered.

[MarkJ]

Originally Posted by brettnkay

"No Charts Available" and just a black screen.

Any suggestions? .

I got that once when playing witht the chart packages. It was looking at the South Pole! So I just scrolled up. It was a bit bizzare. I dont know if thats what your problem is.

Mark

[Extemporaneous]

Originally Posted by bdbcat

Ahoy black-screeners....

This begins to make sense now.

opencpn Beta 1216 indeed sets the application locale to the current user default. This is new.

He further sets (but only for linux) the numeric format to be "C" compatible, which overrides any locale setting, and forces the use of '.' as the decimal separator. This is done to correct a bug in the wxWidgets/clib code for reading numeric values as are found in the config file.

So, the problem: On a windows box, the numeric format is whatever is specified for the user default locale. If the locale uses ',' instead of '.' for decimal separator, then opencpn mis-reads the config file values for initial lat/lon and other stuff, and there are no charts in outer space, or wherever it ends up.

Correct Solution: force "C" numeric format for all platforms. Duh..,

This will be in the next Beta, coming in a day or so.

Anybody see any flaw in this logic?

Sorry for the run-around on this, and thanks Cagney for the ringing bell.

Dave

I believe they found the problem.

Regards,
Extemp.