Charts

[sinbad7]

Leo..

Try to contact the SCCOOS for information regarding their map overlay technique:
They have a lot of experience in this field.

Have a look at the overlays from Los Angeles harbour below. Note the opacity slider at the bottom right of the map which can adjust the intensity of the road map overlay.

[oem]

Concerning map overlay techniques I made these attempts in Google Earth (a different thread).

http://www.cruisersforum.com/forums/...tml#post367856

And it's quite easy and quite impressive to see the nautical maps on a satellite background. So Google Earth has some features to take advantage of. The problem is copyright, so OpenSeaMap is still the option to use, based on all the experience with OpenStreetMap.

And I'm sure free maps in OpenSeaMap will have to be based on manual input (It's not legal just to overlay with copyrighted maps). So I made some attempts on overlay'ing maps on GE and then 're-drawing' based on shore-lines, depth-indications etc.

My attempt to re-draw, based on overlay on GE is below. The read line is a 'depth-line', the other marks are attempts on depths-input. The resulting KML-file contains all information to display. The link www.earthnc.com has a lot of features using KML and Google Earth.

It's a huge task, but still possible. The seamarks (at least for Denmark :-)can easily be found with GEO-coordinates and updated automatically).

So I think OpenSeaMap is the system to use, and the direction forward. Possibly with KML input as a supplement.

Actually I sent a mail to Olaf Hannemann on the e-mail address above. So I'm waiting to hear more on the possibilities of using KML as input language to OpenSeaMap. And also on coordinating the S57-standard with OpenCPN.

[sinbad7]

oem...

Quite agree with you.. OpenSeaMap is the ONLY open source map system available as far as I know. It i also S-57 based so it should not be difficult to make it compatible with OpenCPN for those who know how.

Using individual,transparent OpenSeaMaps for overlay on sea maps already existing on the users own PC's to produce workable .kap charts is a task which should be done by the users themselves for obvious reasons. We do however need help from the technically oriented to as far as possible automate or 'humanize' the process for us mere mortals.

Advice on how to convert a bit map into a transparent/see through bitmap is much appreciated. Does Gimp or Inkscape perform such a function and if so,HOW?

[oem]

Tore

In Google Earth it's very simple to add a chart overlay. Keep your chart as a JPG, BMP, and then do as indicated on my attached picture from GE. The transparency can be adjusted, - as you can see under 'Gennemsigtighed'. The geo-coordinates can be entered as 4 corners or as North, South, East, West. To the left in my picture you can see that I have 'overlay'ed all charts from 'Det levende søkort' in Denmark. Then I can click then on and off. For actual sailing of course only possible if the GE places have been cached, but for planning it's incredible (I think).

Fugawi has made it as an unsupported 'plugin', - see also attached picture, - however they still miss the transparency feature. But it should be simple to make.

[idpnd]

Originally Posted by sinbad7

Advice on how to convert a bit map into a transparent/see through bitmap is much appreciated. Does Gimp or Inkscape perform such a function and if so,HOW?

You have to make a transparent layer.

[sinbad7]

Hi all..

You'll be pleased to know the transparent overlay method actually WORKS!!

I used an old C-Map cut out from Rostock and overlaid it with a transparent version of OpenSeaMap roughly the same scale. This is just a test to see it works.. When it is adjusted properly I will convert to .kap and can use in OpenCPN.

See attached sample..

[sinbad7]

A better match but still not full scale..

Is the OpenSeaMap scale based on inches to the NM?

[idpnd]

How's your Brazilian Portuguese coming along Torre?

[sinbad7]

How's your Brazilian Portuguese coming along Torre?
__________________
sv Libertalia

Just about non existant I'm affraid.. My wife speaks perfect English sooo ,...

Regds
Tore

[sinbad7]

Geting there slowly,but the problem is to find the EXACT scale of the transparent OpenSeaMap. I have used a nautical scale calculator but the inch to nm scale shown in the map is very in-accurate,I need to have the EXACT scale. It is also possible to manually only use the actual depth of the bitmap,with the end map showing only the OpenSeaMap pluss depths. Need to find a quicker,automatic way to do the job.

[sinbad7]

And FINALLY !! just to show it IS possible...

[mat]

Hi all,
I've just discovered OpenCPN and after a bit of figuring things out, now have it working well on my vista laptop. I'm waiting for a GPS receiver to arrive, and wish I could figure out a way to get gps data from my tomtom or my windows mobile phone (which has GPS).

I live on Waiheke Island in New Zealand, have produced .kap files for the following charts:
nz522.kap
nz53.kap
nz531.kap
nz532.kap
nz5321.kap
nz5322.kap
nz5323.kap
nz5324.kap
nz5325.kap
nz5327.kap
nz5328.kap
nz533.kap
The process certainly took me back to the ?good old days of DOS command lines, batch files etc!

Is there a forum for sharing charts - I assume there is no problem with the NZ charts as they are available for free download anyway?
If anyone wants these files I'll figure a way of sending them.

[idpnd]

Originally Posted by mat

Hi all,
I've just discovered OpenCPN and after a bit of figuring things out, now have it working well on my vista laptop. I'm waiting for a GPS receiver to arrive, and wish I could figure out a way to get gps data from my tomtom or my windows mobile phone (which has GPS).

There seem to be some references although it could be tricky

Is there a forum for sharing charts - I assume there is no problem with the NZ charts as they are available for free download anyway?
If anyone wants these files I'll figure a way of sending them.

There's been some discussion about this, my first guess would be a NO as free download does not usually imply right to republish willynilly. I suggest you check for conditions on the site you downloaded them from. There could still be some subtle sharing by email but offering them on a public server may not be the best idea.

You've gotta be pleased your gov is offering these taxpayer funded maps for free at all!

[GPS-Marco]

Originally Posted by mat

Hi all,
I've just discovered OpenCPN and after a bit of figuring things out, now have it working well on my vista laptop. I'm waiting for a GPS receiver to arrive, and wish I could figure out a way to get gps data from my tomtom or my windows mobile phone (which has GPS).

I live on Waiheke Island in New Zealand, have produced .kap files for the following charts:
nz522.kap
nz53.kap
nz531.kap
nz532.kap
nz5321.kap
nz5322.kap
nz5323.kap
nz5324.kap
nz5325.kap
nz5327.kap
nz5328.kap
nz533.kap
The process certainly took me back to the ?good old days of DOS command lines, batch files etc!

Is there a forum for sharing charts - I assume there is no problem with the NZ charts as they are available for free download anyway?
If anyone wants these files I'll figure a way of sending them.

Hi Mat, I'm working right now on the NZ5* charts. It would be interesting if you can describe how you have calibrated the maps and it should be useful if you can share the calibration data.

I'll share my calibration data for NZ5* as soon as I've completed the set (unless there is some urgent need...).

Ciao, Marco.

[kerrydeare]

Originally Posted by idpnd

... You've gotta be pleased your gov is offering these taxpayer funded maps for free at all!

Well, not quite I'm afraid. In the US where I'm based we can download a wide range of navigational materials including charts and publications. However we do indeed pay for these materials every time we make "donations" to the Internal Revenue Service. I am happy to have choices like this, but I would not call them "free." All the same I have recently made contributions to the Canadian Hydro Office who, when it comes to navigational materials, evidently don't see things quite the way they are seen by their southern neighbor.