Help / FAQ

[bcn]

Today I had a longer telephone chat with the gentleman in charge for the InlandECDIS editions at the German WSV.

The decision for the naming of the download links - including the release date - has been taken to ensure that a user gets directly an information about the actual edition. To prevent user errors.
Not much to object , I would say. They do not want to modify this.

He is open to hear proposals from our side what might be done to help us to have a stable download link.
In general the European agencies are using the same structure for the InlandECDIS exchange sets.

Dan, would it be possible to see what the Netherlands did? In theory they are in the same boat as WSV.
A solution that comes to our mind to preserve the human readable format and gives us a stable link?

Hubert

Btw.: The gentleman from WSV has now upgraded his office PC from OpenCPN 4.0 to 4.8

[rgleason]

Bcn
How about having dual url links or an alias url that allows us and others to reference a stable url?

There must some good way of doing this.

[nohal]

The problem with the German IENCs downloads is simple: They invested effort into requiring user interaction to download files from their site and disabling automated downloads - there simply is no way to download the charts until the user makes that click on the "... herunterladen" button. Or at least there wasn't at the moment I developed the plugin and integrated these charts into it.

The ideal solution of course would be if they could generate the chart catalog XML themselves and publish it on a stable URL and make the chart archives directly downloadable from the URLs in it. Technically, this task is trivial, which says nothing about the feasibility for the German WSV.

The fast thing to do is to update https://github.com/chartcatalogs/cat...NC_Catalog.xml manually - The thing I do whenever I know there is an update and have time, but of course can be done by anybody.

Pavel

[transmitterdan]

Pavel is right. What has to happen is only 3 things.

They need to put at a never changing URL a file that contains in XML format the information about all the latest chart files (URL to actual chart file, date and time of issue, etc). The NOAA format would be best.

Then they need to put the actual ENC chart files on a server where any web browser with the URL of the file can download ithem They must not make it some crazy captcha thing or other web programming trick that requires human "clicking". The URL of the actual chart files can change with each new edition of the charts.

Finally they can use compression as long as it is one for which there is opensource software to decompress (e.g. simple zip).

They then have to update the XML file with the new chart file names and other details each time a new edition comes out. This can all be easily automated at their office so publishing the new file names should take only a few seconds. It is not hard to understand how the NOAA system works so would be nice if they looked at it and used the same catalog XML file idea.

If they understand that easy automated downloading makes it much more likely that watermen will have the latest charts maybe they will see the wisdom in doing the needful.

[bcn]

Dan..

you will have it at hand:
where can we find the NOAA XML structure/description/example ?

Hubert

[bcn]

Found this entry link:
Chart Downloader for NOAA ENC®

any additional docs about the XMLs?

[nohal]

Hubert...
NOAA uses ISO 19139 Xschemas (Index of /2005) for the catalogs - we need a very, very, very, minimal subset of the data this format covers and they publish for our use-case.

For IENC charts, the format used by USACE (Catalogs), which we also support is much simpler to implement and it directly targets rivers (unfortunately it was designed thinking only about US looking the units used in the name of the tags). And even from that we are good with a limited subset for the chart downloader. As far as I can tell there is no documentation for it, but I can write some documenting the subset we use if they are interested in implementing it.

We can of course support even some other format if it suits WSV better.

Pavel

[transmitterdan]

At item 3 on that page is a link to their XML catalog file. It is self explanatory from my point of view. I don't know if NOAA has a document describing the file format. I would imagine they do and if German hydrographers asked NOAA I feel sure they would be happy to share it.

[bcn]

Pavel, Dan...

thanks for the additional inputs.
Fired a mail with the proposal to WSV.
So wait & see.

Hubert

[mediran]

Hello friends,
I have a question to opencpn Dashboard and nmea converter. I Hope, this place is ok? When I connect a VDO-Logic wind with nmea VWR data, I see the apa and aps in a dial. But when I use the nmea converter and create the virtual VWR data like $IIVWR, 50,L,10,N the nmea logger Shows These data, but not the dial.
Thanks for help and best ragards
Marcus

[Hakan]

Originally Posted by mediran

Hello friends,
I have a question to opencpn Dashboard and nmea converter. I Hope, this place is ok? When I connect a VDO-Logic wind with nmea VWR data, I see the apa and aps in a dial. But when I use the nmea converter and create the virtual VWR data like $IIVWR, 50,L,10,N the nmea logger Shows These data, but not the dial.
Thanks for help and best ragards
Marcus

Marcus...
The VWR sentence would read like this to be understood by Dashboard:

    **        1   2 3 4   5 6   7   8
    **        |   | | |   | |   |   |
    ** $--VWR,x.x,L,x.x,N,x.x,M,x.x,K*hh<CR><LF>
    **
    ** 1) Wind direction magnitude in degrees
    ** 2) Wind direction Left/Right of bow
    ** 3) Speed
    ** 4) N = Knots
    ** 5) Speed
    ** 6) M = Meters Per Second
    ** 7) Speed
    ** 8) K = Kilometers Per Hour
    ** 9) Checksum

So in your case: $IIVWR,50,L,10,N,,,,*55
Not: $IIVWR, 50,L,10,N (A space before "50", missing commas and no checksum)
Håkan

[mediran]

@ Hakan: thanks for these informations

If i don't type the checksum, the nmealogger shows the calculated checksum. When i type the checksum , the dial is working. When i delete the checksum, the dial is working. But when i restart opencpn, the dial doesn't work.

[mediran]

Hello friends, is it right, that the heaviside function in nmea converter is called hvi? And is there a possibility to change an L or R to a number that can be calculated in the heaviside function?
Thanks and best regards
Mediran

[mediran]

.....and another question comes up:
The opencpn dial for true wind Direktion & speed looks for which nmea-data?
Can anyone tell this?
Thanks and best regards
Marcus

[Hakan]

Hi
On a Win10, not mine, got this when looking in tools plugins. O freezed and couldn't exit.

15:34:10: PlugInManager searching for PlugIns in location C:\Program Files (x86)\OpenCPN\plugins
15:34:10: Varning: Caught MainLoopException, continuing...

Never seen. Anyone??
Thanks/ Håkan