Great Circle Routes with Chart Work

[Livia]

I want to create a great circle route for our use en route to the Marquesas and then import it into OpenCPN.

I have downloaded Chart Work.
I enter coordinates and press "GPX out".

I've checked the Windows/NavigationalAlgorithms/Chart Work... directory. Nothing. Where are the files??

Also, I have no idea what B1 and L1 are so I'm guessing there too.

If my departure/arrival coordinates are:
22.67N 110.33W
0N 128W

What is B and what is L? How do I designate N/S and E/W?

Does the program perhaps not work with Windows 7?

Thanks in advance for any help, Livia

[PjotrC]

Livia,

On my Vista the key is to invoke these programs with administrator privileges, so maybe on W7 it is the same problem... Both ChartWork and Derrota create the Great Circle route in the respective program installation directory.

Good luck,

Piotr

[lolarose]

Originally Posted by Livia

Also, I have no idea what B1 and L1 are so I'm guessing there too.

B1 – Latitude

L1 – Longitude

[Livia]

Thank you both.

That worked! Right clicking on the icon for the chart works program and running it as an administrator allowed me to create the great circle route.

B is latitude and positive numbers are N, negative S
L is longitude and positive numbers are E, negative are W

I hadn't been adding the necessary negative before my longitude causing my route to be on the wrong side of the globe.

[Livia]

PS - the great circle route is almost the same as the rhumb line in this instance - silly me.

[wdkester]

Chart Works seems to fail for short courses. From the SW corner of Haiti to Panama (the course is short and nearly straight) using B1=18.66, L1=-75.08,B2=9.62,L2=-79.67, I get a huge W shaped course. When I entered L2=79.67 without the minus sign, I got the expected GC couse.

Anybody know how to contact the author?

[nohal]

David...
About - Navigational Algorithms or Andres_RG here on the forum, so you can try to PM him. Haven't seen him around for quite some time though.

Pavel

[Andres_RG]

the problem is that the GC, for differences of longitude less than 5º do not have sense.

If you use a dL > 5º, see the attached PDF, GC is the same as rhumb line or loxodrome.

(See documentation for details)

[JesperWe]

Andres, given that your programs seems to be quite popular here: Would it make sense to make a small but easy modification to improve integration?

I have implemented copy/paste for a complete position with lat+long in a single click in OpenCPN (for next 3.1 beta), it would be rather easy for you to do the same I think.

Send me a mail if you want to work out details...!

[Andres_RG]

Originally Posted by JesperWe

Andres, given that your programs seems to be quite popular here: Would it make sense to make a small but easy modification to improve integration?

I have implemented copy/paste for a complete position with lat+long in a single click in OpenCPN (for next 3.1 beta), it would be rather easy for you to do the same I think.

Send me a mail if you want to work out details...!

Yes, I will try!
Please tell me when the feature is available in beta version.

[JesperWe]

Originally Posted by Andres_RG

Please tell me when the feature is available in beta version.

It will be in the next beta (not in the current 3.1.714). That will be announced in the forum as usual.

(The code is on Github now if you want to build yourself)