ochart rendering - cut off labels and symbols

[quantenschaum]

ochart rendering - cut off labels and symbols

[free-x]

With "ochartsng" it looks much better ;-)
Did you tried?

Although I would admit that the light sectors are too short

[quantenschaum]

Very nice. Is this is still work in progress? How can I get this running?

• The sectors are still too short, yes.
• The labels still show only one sector as it seems.
• It seems not to get clipped anymore.

Just out of curiosity: How does the rendering work?

• charts are encrypted in the oesu files
• binary lib from ocharts derives the decryption key by some secret magic from hardware and os properties
• ocharts lib provides an api to access the decrypted vector data
• some lib (which?) renders this vector data on the screen or into a buffer/file
• the screen/buffer is captured/converted and cut into XYZ tiles and served to the browser

Does it work like that? Which lib does the actual rendering? And to what extent are you actually able to influence the appearance of the rendered chart?

[free-x]

Very nice. Is this is still work in progress? How can I get this running?

Sourcecode you can find here on github
https://github.com/wellenvogel/ochartsng

Since last Saturday is public beta available
https://www.segeln-forum.de/thread/90260-avnav-ocharts-jetzt-auch-f%C3%BCr-android/
https://www.wellenvogel.net/software/avnav/docs/hints/en_ochartsng.html?lang=en
Are you stil OpenPlotter 3 user? Right?
If yes, you need to activate preview repository

deb [signed-by=/usr/share/keyrings/oss.boating.gpg] https://www.free-x.de/deb4op bullseye-preview main

Then

sudo apt update && sudo apt install avnav-ochartsng

[free-x]

BTW...ochartsng can also display S57( ok, after conversion to SENC)

Here is Screenshot of Waddenzee from RWS

[quantenschaum]

Thanks, just looking into it. Impressive!

[wellenvogel]

Just out of curiosity: How does the rendering work?
charts are encrypted in the oesu files
binary lib from ocharts derives the decryption key by some secret magic from hardware and os properties
ocharts lib provides an api to access the decrypted vector data
some lib (which?) renders this vector data on the screen or into a buffer/file
the screen/buffer is captured/converted and cut into XYZ tiles and served to the browser
Does it work like that? Which lib does the actual rendering? And to what extent are you actually able to influence the appearance of the rendered chart?

Depends on the version...
The "old" ocharts support completely used the OpenCPN o-charts_pi plugin.
The new one uses an own implementation (with some code taken over from the old one and from o-charts_pi).
The old one was using the X11 infrastructure for rendering (including OpenGL).
The new one does all the rendering completely in memory.
And both are just rendering single tiles. Many of the problems with the old implementation are caused by this fact.

For customizing:
You can adapt a lot of things via the settings.
And finally you can dramatically change a lot with editing the xml files. I just plan to make this a bit more user friendly (i.e. having a separate user.xml to be layered on top of the existing settings).

[quantenschaum]

Awesome work!

Just quickly one thing I noticed: Spot soundings are missing on drying heights.

new -- old

[wellenvogel]

Which display category do you have?
The new one has default "standard".

[wellenvogel]

OK - I can also see this issue.
Thanks for finding this!

[wellenvogel]

New daily tonight.

[quantenschaum]

display category = all

another thing: too many digits after decimal for topographic heights or mag variation (not a problem, but cluttering)

[quantenschaum]

floodlight icons are out of place

[wellenvogel]

would you mind creating issues at https://github.com/wellenvogel/ochartsng/issues?
Makes it easier to track the particular issues.
Anyway thanks for your findings. Those always really help a lot!
Btw: If you are interested in trying the whole process also on Android just send me a mail with your o-charts account and I could get a test license for you (also valid for linux use of course...).
As you are looking at things carefully I would really be interested in feedback from your side.

[quantenschaum]

I will create new issues there. - Don't see it as complaints, just feedback, so you know about it.

Sure, I would test it on android, if that helps you. I just installed the avocharts-beta-20240222 and have avnav-20230705 on android 13. I tried to add s57 charts (zip with senc files from opencpn), but when clicking on "upload zip" nothing happens, no file chooser opens.

[wellenvogel]

for the first 2 points I already created issues.
If you launch the UI from within AvNav you don't have a file chooser.
Just launch it directly from the avocharts app - or connect to AvNav with a browser (e.g. from your PC - easier upload any way).
I will extend AvNav itself later for a file browser.

[quantenschaum]

that worked

[quantenschaum]

Moved to ochartsng repo