OpenCPN General

[StoneCrab]

Does it make any difference to OpenCPN how much memory you have on your Pi?

There is a pretty good difference on a Pi4 for 2GB vs 4GB. Does OpenCPN use the extra memory or doesn't it matter?

I bought a Pi4 with 4GB, more for psychological reasons... who wants to experience 2GB shaming, right?

But then again, I have some of the original Raspberry Pi's laying around. I think the memory is only 512mb, yet OpenCPN will still install. It is very slow, but so is the processor. With everything being so manual in Linux, it got me wondering what process does the memory management and how much impact having more memory really has on a program that can fit in half of a gig of memory.

If anybody knows, I'd love to hear back.

[sailorxyz]

Originally Posted by StoneCrab

Does it make any difference to OpenCPN how much memory you have on your Pi?

There is a pretty good difference on a Pi4 for 2GB vs 4GB. Does OpenCPN use the extra memory or doesn't it matter?

I bought a Pi4 with 4GB, more for psychological reasons... who wants to experience 2GB shaming, right?

Depends on how many charts you have open at the same time... Also what other apps you may have running.... You don't "need" 4gb to run OpenCPN but it sure will not hurt.

[transmitterdan]

Originally Posted by StoneCrab

Does it make any difference to OpenCPN how much memory you have on your Pi?

There is a pretty good difference on a Pi4 for 2GB vs 4GB. Does OpenCPN use the extra memory or doesn't it matter?

I bought a Pi4 with 4GB, more for psychological reasons... who wants to experience 2GB shaming, right?

But then again, I have some of the original Raspberry Pi's laying around. I think the memory is only 512mb, yet OpenCPN will still install. It is very slow, but so is the processor. With everything being so manual in Linux, it got me wondering what process does the memory management and how much impact having more memory really has on a program that can fit in half of a gig of memory.

If anybody knows, I'd love to hear back.

A 512MB Pi is not an effective OpenCPN platform.

By far the best low cost CPU platform is the Pi4. OpenCPN uses less than 1Gb of memory itself but the OS needs memory too. A 2Gb Pi4 is just as fast as the 4Gb running O.
But if you want to load up on other programs running simultaneously then you have to decide if 4Gb is worth it. The Pi4 is still not good when it runs out of memory and starts swapping to the microSD card. That’s what kills the cards.

If you plan to compile OpenCPN on the Pi4 then i would recommend 4Gb.

[harbourmaster]

Hi there,

Just wondering if there is the ability to create and display constant radius turns as part of the passage planning tool in open CPN? it is usually only used for larger vessels, but it is based on the concept that when a vessel alters course it follows an arc of a circle, the radius of that circle is a function of the speed at which the vessel is travelling at and the rate at which it turns. The faster the vessels rate of turn the tighter the radius, the faster the speed of the vessel for that same rate of turn, the greater the radius of the turn. In anycase, when passage planning for large vessels the turns are planned as well using a known radius for a specific course alteration. The basic formula to determine the rate of turn required in degrees/min for any given course alteration is:

the speed of the vessel in knots divided by the radius of the turn (in NM)

i.e a turn with a planned radius of 1nm at a speed of 10 knots requires a rate of turn of 10 degrees a minute.

A turn with a radius of 0.5nm at 10 knots requires a ROT of 20 deg/min

A turn with a radius of 0.25nm at 10 knots requires a ROT of 40 deg/min.

And so on.

if there were a way to depict the track for a planned radius of an alteration in the passage planning tools it would be incredibly helpful.

Thanks in advance.

[rgleason]

This sounds more like a drawing tool application. Is the intent to actually follow a course?



If it is depiction of the radius then try using Ocpn_Draw_pi using a combination of Guard Zones and other objects. Perhaps this is something Ocpn_Draw could add?

[P_Dub]

No, this is done automatically when drawing route in ECDIS. It does the rounding in between 2 course.
Have a good day.

[wholybee]

Originally Posted by waynetmazan

wholybee, thanks for help.... now I need to figure out what "sideload is " ;-)

Late to reply-sorry. Sideload refers to a way to install an app on a device bypassing the official methods.

Basically, you install OpenCPN on another tablet, then transfer it to the Fire.

Install "ES File explorer" on both devices.
Install OpenCPN on the device that can access the play store.
Run ES File explorer on that device to create and APK file.
Run ES File explorer on the Fire to transfer the APK file to it and to install.

It's been a while since I did it so I can't go into more specifics, but that is the basic process to get apps from the Play store to the Fire. Note that not all apps will work, but OpenCPN does.

At some point I am going to try and get opencpn to run on my google tv.

[StoneCrab]

Originally Posted by wholybee

Late to reply-sorry. Sideload refers to a way to install an app on a device bypassing the official methods.

Basically, you install OpenCPN on another tablet, then transfer it to the Fire.

There are a number of things that I want to do with OpenCPN that aren't documented (anywhere I've looked in any case). Sometimes they are mentioned without any how-to. As a result, I've spent a lot of time getting OpenCPN twisted up and then reinstalling it and starting over. This post is a bit long, but I wanted to share some of what I've experienced and what I've learned. I can't be the only one flattening my forehead on this.

I do not have a strong, consistent or quick internet connection, so the biggest hassle when reloading is the need to update and upgrade or install the plugins. To this end, I've tried copying off the plugins and charts onto a USB drive and then just copying them back over to the correct directory after an install.

With the charts, this works on a practical level in that I can see all the charts but when I rebuild the database, update and try to download newer ones, the system logs errors. It doesn't download the new charts.

By copying over the current charts on top of a new install, I was also surprised to see charts that weren't visible after doing the "normal" download process. The "standard" process of creating the directories, groups and then download did not show all of the charts, even though they were downloaded. After copying them to the new install, my "non-standard" approach, they popped up. The Atlantic Pilot charts and wind roses never showed on with the standard download, for instance. (I still haven't figured out why)

I also filled up my SD card (or nearly so) and then did a chart database update and rebuild on the Chart Files page. This resulted in a "S57 Cell Update failure"... "No updates could be applied." "ENC features may be incomplete or inaccurate". of course this was followed by "Check the logfile for details".

Of course the logfile would be more specific, if I knew which logfile or the name of the logfile. Not to complain, but rather to point out that the target audience for this software is generally individuals who are smart enough to figure things out and dumb enough to try. I'm more the latter, with repetitive acts of pain, but capable with detailed documentation.... or enough tries that eventually I start to see patterns reveal themselves... That is to say, if I was paying enough attentions to remember what I saw.

So often with this software I find myself looking at a warning or info box on the screen which could tell me exactly what I need with just a few more words, like naming the logfile name associated with a S57 Cell update. I have a few more examples I'll share later.

In this case I deduced that my S57 Cell Update failure occurred because I was extremely tight on SD card space. I did find several log files, after checking "show hidden files" in file manager. I never got any juicy tidbits from any of them, but the end result, surprised me.

Following the S57 error, a restart of OpenCPN resulted in a "Failed to write to lock file '/home/pi/.opencpn/_OpenCPN_SILock'"

OK, so I deleted a bunch of chart files and relaunched. OpenCPN will fill the screen and appear to kill itself. Yet it left a zombie process in the background resulting in "another instance" type of error for subsequent relaunches, with OpenCPN never resolving to a workable state, even after reboots.

I decided to look at the contents of the lock file after freeing up the SD card space. The contents looked like cartoon swear words, so I deleted the contents and rebooted. Then it complained about an invalid lock file. I would have thought that the lock file is created on launch and deleted when the process is stopped. Why does it depend on "hidden file" curses for validity? Sometimes I think there is a level of programmer humor afoot.

Undaunted, I tried to restore my last working image from this Samsung installation onto a spare SanDisk SD card. Even though both are 32 GB, the image will not write onto the different brand card... While this may be common knowledge, I never heard of this problem.... so I'm sharing this foible with y'all.

I was still messing around with the Samsung installation trying to cure its ills, thinking that I could restore OpenCPN to good health and learn something in the process but I decided to verify that the image restore problem was manufacturer specific instead. So I restored the image back onto the Samsung SD card. It was successful restore.

Now I have two cards which should be essentially the same installation with the exception of the Chart source. In OpenCPN, they look and act completely different. I have way more charts available on the install with the copied Charts, but I can't update the charts, nor can I install all of the plugins on that installation.

Another way that I've been breaking OpenPlotter/OpenCPN has been as the result of my attempts to have multiple network cards installed and share the internet connection from one of the WiFi cards out over another using the AP function. The manual warns against doing this with only the onboard WiFi saying that it is unstable, but then the documentation only really describes a USB tether approach.

Since I was avoiding something else that I needed to get done, I dove into the multiple WiFi installation with a second laptop at hand for reading and downloading methods and instructions. After many wpa_supplicant and interface configuration files mod's and no luck, I tried swapping out WiFi dongles.

I would get the WiFi dongle to work, but when I'd go into OpenPlotter and turn on AP, everything would quit working. VNC would connect but not on 10.10.10.1 but rather on the IP address assigned to OpenCPN by the router.

I was basically installing the dongles manually. The other day, I click on the OpenPlotter>network>"Install WiFi Drivers" button with my new WiFi dongle in place and lo and behold it starts working. (this was on a clean install) So with it working, I was dying to know what the system did that was different, so I look into the interface file and wpa_supplicant... only to find nothing added. Weird, but since I have a second adapter working, I add another "N" adapter and wrote down all the realtek chips that the included drivers will work with.

At that point I have three WiFi adapters working at the same time. (makes no sense, but worth the experiment) I tried connecting each to a different network. That worked well. Exciting right? So the next big step was to turn on the AP to see if that would work as well. WLAN9 came online and I could connect with VNC on 10.10.10.1. The AP function wasn't routing the internet though, so I gave up for a while. Getting back to it an hour later, the AP, which was set to "Auto" sorted itself out and was routing as it should. I could pick the OP SSID from another laptop and get onto the Internet.

It always concerns me when software cures itself after taking a break. What did it do and why couldn't I make it happen?

So after several weeks of manual, terminal based, "sudo" installations of the second adapter, following all the recommended procedures, I've learned that the AP function will only work if you are using an approved chipset with the included WiFi drivers.

While it gives you control over Wlan0, Wlan1 and Wlan2, it doesn't give you a clue as to which Wlan is associated with which adapter. lsusb shows the adapter, chipset and its address, but no clue to its identity within the system. ifconfig and iwconfig contribute additional information as well but still no association to the Wlan identity. This does not appear to be a fixed association either. The manual advises you to leave the shared AP device in Auto since this assignment can change. My experiments show that the assignment is indeed random.

As it happened I had a dual 5dB antenna AC WiFi dongle with an approved chipset that works really well. I plugged it in and hit the "Install WiFi Drivers". The software found the chipset, downloaded the driver and got it up and running. I've had it working at 5 GHz with great speeds. The only caveat with that one is that the Pi will not boot with that dongle attached. I have to unplug it momentarily, at which point the "boot" will take off, and then I plug it in again. No errors, but it interferes with the boot process somehow. (This might be a useful option for someone else staring at a blank screen wondering why its taking so long)

Another two items which came out of this: VNC needs to be turned on in raspi-config or with the "Raspberry Configuration" menu item under the "Interfaces tab" after a fresh install of Openplotter. This never used to be the case, but has been my recent experience. The second item is that with the charts installed, I get an advisory popup saying that OpenGL needs to be turned on for the overlays to work.

OpenGL is another one of those messages that could benefit by adding a few words to tell you where.... There is an GL driver in raspi-config under "Advanced Options" but the description says that it is "Experimental" and there is no mention of "Open". (Nothing in the Raspberry Configuration menu"... OK this is all a big experiment right, so why not? ... Turning that on doesn't do anything.

I did finally find the OpenGL enable button under OpenCPN 5.2.0>Settings>Options>Display>Advanced tab. The setting check box is at the very bottom of the Advanced screen, out of view with my resolution unless you scroll to the bottom. I missed that button several times.

Overlays work like a charm once this is checked, but it begs the question: If it is needed why not just enable it automatically? or If it requires a warning or advisory message, why not add the enable button to the warning box or at the very least leave a hint as to its location. That would provide a much better user experience and faster implementation.

Future work on this system will consist of sorting out my space limitation by either trying a larger SD card, external charts, or transferring the system to a USB SSD. I've read that going above 32 GB requires a different formatting system, but I haven't read of anyone reporting success with that approach.

I need to sort out why the charts are enabled differently when you copy them in, without downloading them, and how to end up with charts that can be updated successfully. I've been wondering if I should just dedicate a USB port to a thumbdrive with the charts installed there. That would free up my SD card for the system and plug-ins.

A fair criticism might be that I should only load the charts that I need at the time, but what fun would that be? Plus by maxing out the system, I am also breaking it and finding that I may think that I have all the charts available for an area because I've downloaded them, but in reality I can't see them all. (for reasons that I haven't figured out yet)

I also want to try all of the Plug-ins. I don't know if it is related or not, but the system with the copied Charts isn't allowing the addition of plugins right now. I haven't had time to troubleshoot it yet.

I also want to try additional dashboards. The documentaton on Graflex and InfluxDB just shows some charts with no explanation. The chart objects that you are supposed to be able to copy onto the screen are located.....? I had it running on a previous install for a while and then InfluxDB and Graflex quit on startup with no specific errors. Restarts weren't a cure. They remained down. After I abandoned that install, the next one ran both programs just fine.

What I find interesting about this system is that I am not "writing code", yet each install ends up having slight variations. When I am contemplating an amber liquid, thinking about this, I conclude that there is a prescribed workflow that needs to be implemented, (and documented), in order to have consistent results. (discounting my intentional abuse of the system) If I stumble across the correct order of steps, I'll share it. On the other hand the smartest guy for this isn't sitting in my room, so if this is old hat and drivel for you because you never have any trouble with your installs, please contact me and share the secret order.

I am most amused by the Wifi dongle installation. I spent so much time in terminal mode when the solution was just having the correct chipset and hitting one button in the desktop GUI.

[harbourmaster]

Originally Posted by P_Dub

No, this is done automatically when drawing route in ECDIS. It does the rounding in between 2 course.
Have a good day.

Thanks for that,

The reason I ask for those interested, is that one of the functions I am actually using open CPN for, is to assist with the creation of passage plans that form part of a pilotage passage plan to be handed to a ships master during Master / Pilot exchanges. The passage plan being drawn up in Open CPN, then screen shots can be made of that plan and attached with any additional notes which may be pertinent to share with a ships master.

I am also currently in the middle of a channel re-design project where I am reviewing the aids to navigation in that channel. I would like to be able to set the channel up with transits for wheel over positions for the maximum size vessel the channel is classified for. The depiction of the constant radius turn would allow experimentation of AtoN placement within open CPN. Once positions had been established they can then be transferred to a simulator model for testing.

Thanks for the feedback.

[P_Dub]

I did requested this a long time ago, without success; hope you do.
Regards.

[Rasbats]

Harbourmaster...

D...n you have me interested. I will take a look over the next month or two. The route will not work as a simple GPX. But we could calculate start/end of turn. Have you considered using RTZ format? Updated ECDIS will read this format and perhaps your simulator. And the radius would be drawn.

Mike

[rgleason]

Stonecrab, this all sounds like a mess. I would start over:


1. Using your tablet, cleaning up your previous install, and then starting over using a good reliable internet connection.



2. Using a desktop or laptop connected to the internet directly and download the necessary install image for Opencpn. Then using your desktop version of Opencpn and Chartdownloader, download the chart files you want. Then copy those files to your SD card and install them into your Tablet.

[P_Dub]

Mike
The rtz file format dos not work in OpenCPN.
Thanks.

[bcn]

Mike has written a helper program to import/export RTZ to/from GPX.

[wholybee]

Originally Posted by StoneCrab

There are a number of things that I want to do with OpenCPN that aren't documented (anywhere I've looked in any case).

Snip...

I would suggest starting with a basic OpenCPN install on a windows laptop. Get everything working and learn how it works together. Things like sharing NMEA data from OpenCPN on windows is relatively simple. Charts and plugins are easy to manage etc. Once all that works, then dive into OpenPlotter and Android.

As it stands, you have a lot of things that aren't working properly, and not all of those problems are related to OpenCPN.