OpenSeaMap - S57-Based

[sinbad7]

idpnd..

The charts are not shown full screen but you can set your browser in full screen modus which helps a little. Otherwise I can't see that the charts are directly downloadable.The system seems a bit sluggish at the moment but it will no doubt improve.

The main thing is that we now have proof that it WILL work with a little engineering by our mapping specialists.

[janp391]

Sinbad7
Nice and good work Norway!
It is also possible to look on Swedish navcharts through the internet
Kartor, vägbeskrivningar, flygfoton, sjökort & mycket mer på eniro.se
May also bee useful?
//Jan

[sinbad7]

idpnd... and //Jan

I discovered you can download FULL page ECDIS charts,soundings and all from the Norwegian Coast Guard's web page. The overlay seems to be C-Map.
Then,it's easy to convert to .kap format.

Thanks Jan for the tip about Swedish waters,I will certainly look into it.

[sinbad7]

Living proof of an S57,C.Map based conversion from the Norwegian Coast Guard. Freely downloadable in full screen size but not for navigation?

[Tim B]

OpenSeaMap looks a lot like OpenStreetmap to me (and no, I haven't looked into the genealogy of the projects). OpenStreetmap is successful in part because altough there are a lot of roads etc to record, they are at least reasonably easy to define. Charts are a bit harder, because we're not only interested in what we can see (buoys, marinas etc.) but also water depths. I don't know of anyone with scanning sonar who could record enough soundings, do you?

It might be worth keeping an eye on, and could be useful for updates.

Tim B.

[sinbad7]

Tim B.

Have a look at my #19 above and see what the Norwegian Coast Guard have been able to do with OpenSeaMap. The ECDIS chart is an overlay on the OpenSeaMap.

See the Norwegian Coast Guard maps here:

OpenSeaMap is being launched at the Duesseldorf Boat Show this month.
Yes,it's early days,but it looks very promising..

[sinbad7]

Hi all..

I have constructed a large .kap chart of the Oslo fjord from ECDIS charts downloaded from the Norwegian Coast Guard site. I used 4 central calibration points as well as the resulting 4 corner geo loc in MapCal to procuce the calibration file.

The problem is,the displayed red chart outline is considerably skewed to the left and the chart calibration is off. Any tips as to how I can straighten this up is much appreciated.

I have attached the calibration file Oslofjorden.hdr.doc and the main Oslofjorden.tif file can be downloaded here:

[sinbad7]

Re my #22

Please note the download link for my 127 color Oslofjorden.tif file is:

By mistake I sent the wrong link previously..

[sinbad7]

GPS-Marco

Any chance you could help me with my calibration problem mentioned in my # 22 ?

Thanks in advance

[GPS-Marco]

Originally Posted by sinbad7

GPS-Marco

Any chance you could help me with my calibration problem mentioned in my # 22 ?

Thanks in advance

Hello Tore.

Can you post the CHARTCAL.DIR you saved from MapCal? As I can see the calibration is actually skewed (rotated) so it is normal that you see in OCPN the chart exactly vertical (SK=0) while the red border is rotated.

Another point: update your mc2bsbh to the newest version.

Ciao, Marco.

[sinbad7]

Thanks Marco..

I have attached here the original CHARTCAL.DIR.doc

I even at one stage used 13 central calibration points allong both sides of the Oslofjord,plus also saving the 4 automatically generated corner cal.points. but that was even worse. Why does the red border not follow the chart perimeters? I can see from the AIS shipping reports that the positions are way off.

I did not yet install the latest mc2bsbh as I understood that needs even further programs to be installed.?

Otherwise great ECDIS charts from the Norwegian Coast Guard website,don't you think?

[GPS-Marco]

Tore,

1) the chart is rotated about 3.7 degrees left. I've never faced how OCPN handles skewed charts so I cannot give you a final answer. Maybe, since you put very few ref points (4), OCPN is unable to calculate the correct polynomial. You should put at least 15/20 ref points.

2) If you try the attached header, you will notice strange behaviour of OCPN. I just slightly recalibrated the map, I used a new mc2bsbh, then I put by hand a SK=3.7 (that is the skew angle). Of course 3.7 is just an approximation...

3) the only suggestion I can give you to use such maps is to rotate the tiff 3.7 degree to make the north up (I use xnview), then recalibrate. The other possibility is to put at least 15/20 Ref points.

4) No, you don't need any additional SW for using the new mc2bsbh.

Ciao, Marco.

[sinbad7]

GPS-Marco

Thanks for the tip Marco. You are right,the map was skewed 4.5 degrees.
As soon as this was fixed and a 4 point cal in the middle plus the auto corner cal. all is as it should be. The broken lines with letters on the map confused me,thought they were tiles of some sort and not a geo grid.

Regards
Tore

[sinbad7]

Interesting news from the Norwegian Coast Guard which has adapted OpenSeaMap.

The Norwegian Coast Guard is now offering a free charting service for Norway.
The new development is that they are using OpenSeaMap as a base,with choice of up to date ECDIS compatible nautical charts for the entire coast of Norway. Presently only available via internet.

All the nautical charts are collected directly from 'Sjøkartverket' ,the coast guard's charting service. The maps are collected as WMS (Web Map Service) Each time the user pans or zooms the chart,a call is made to the Sjøkartverkets WMS server,making sure you reveive the very latest chart information. If OpenCPN could be made WMS compatible, it would in theory be possible to collect the charting data direct from Sjøkartverket.

About the WMS service:

Perhaps a similar model could be adapted for use with other free charting services such as USA and Brazil.

As the data is presently only available over the internet,I suggested that perhaps arrangements could be made to download particular chart areas prior to each planned trip which could later be updated or deleted as required. This would avoid having to download the entire and huge database.

I have suggested that we could all benefit from a discussion to find a solution to offer a total FREE navigation package to the boating fraternity.

[jonasaberg]

Tore,
Just noticed this thread. Interesting, especially since I live in Kristiansand, Norway. I only have a limited set of Norwegian charts so far.

Did you make a screendump and calibrate it, or did you find a way to download files from the Kystverket site to calibrate? I can't find the links if so...

/Jonas