Chart Converter Recruitment

[manimaul]

Is anyone interested in working with me on creating a kml collection of all the current charts we have been using in opencpn? (NOAA bsb,enc and cmap cm93s)

CM93 will be a little bit more challenging than the s57 and bsbs.

Here are some screen shots of some progress I've had:
(this can be made to look much better and include other essential data)

[manimaul]

Here is a how to for getting started on windows:

1 install osgeo4w (we will be using the gdal portion)
http://download.osgeo.org/osgeo4w/osgeo4w-setup.exe
choose advanced install -> install from internet -> all users -> (use any directory you want) -> direct connection -> select the following
commandline utilities
gdal16
setup
shell
libs
gdal16-python
python-win32

2 the conversions will be command line

to create kml from a bsb .kap file

 
gdal16
gdal_translate -of vrt -expand rgba 18450_1.kap temp.vrt
gdal2tiles -k -w none temp.vrg 18450

to create kml soundings from s57

 
gdal16
ogr2ogr --config OGR_S57_OPTIONS SPLIT_MULTIPOINT=ON,ADD_SOUNDG_DEPTH=ON -dsco NameField=DEPTH -f KML soundings.kml us5wa15m.000 SOUNDG

to create all kml from s57

 
gdal16
ogr2ogr -f KML test.kml us5wa15m.000

[James S]

I don’t see many...OK...any replies....Being a low tech guy any advantages to this may not be readily obvious....can you explain what advantages this would have over existing systems?
What is the projected cost in time and other to complete X?
What type of participation are you looking for in working with you on this.

[cagney]

Good on ya manimaul!

A couple of questions...
Is support for kml coming along i OpenCPN?
Is that part of the project?
What is your vision for the future of .kml as far as navigation is concerned?

Thomas

[manimaul]

Thanks for the replies; these are good questions.

So #1, why?
First, its fun and a learning experience.

Second, I use sat photos in google earth when I plan a trip on my boat, having charts as layers is super helpful. As you can see, the rasters are easy to convert. I have a complete, finished raster library of the puget sound as kml. (Before i knew about opencpn, I used python to plot my position and track into google earth, so you can use it as a supplementary chart plotter.)

Third, this only relates to opencpn in that opencpn uses a modified version of gdal to read s57, bsb and cmap93/3. gdal is the same library I'm using to create the kml files.

#2 kml in opencpn?
I don't know. I can't really speak for Dave. He did mention that he wants to work on grib overlay recently. I suppose this could pave a path to kml overlay.

#3 is that part of the project?
No, the only relationtion to opencpn is gdal and reading cm93/3. And the usefullness of a supplementary program to opencpn.

Above all my number 1 goal is global chart data in an open format (kml).

[James S]

Yeh...so I recognized some of those words....but for the most part I didn’t understand most of what you said.
Sufficed to say I wont be very helpful.
Good luck with this.

[idpnd]

on capcode, you can have a raster overlay on world wind.

although i'm not the greatest fan of copyright and patents, we may get problems redistributing kmls derived from raster/vector charts.. just a thought..

as far as i'd understood, we wanted to have a kml feature in opencpn so as to be able to import google earth imagery into opencpn (where navigation is to take place)?

i would have thought the logical consequence of the tif2bsb discussion above would be to convert google earth images for opencpn in a semi-automated fashion?

[manimaul]

How you can help & roadmap.

You can help be experimenting with the kml and making it look like a proper chart.

You can especially help if you are good with scipting python or perl. As, this is how I plan to post-process the kml generated from gdal.

Roadmap s57:

1 Choose layers to pull out of vectors (ex. SOUNDG, DEPARE, COALNE ... etc) obviously we will want the major features such as depths, depth contours, lights, rocks, wrecks

2 Represent each layer with proper colors, transparencies, symbols in kml and script the process to create the finished kml

[bdbcat]

Pretty cool pix, manimaul....

Here is a heads up on my thinking about KML for opencpn:

I plan to add generic KML overlay capabilities to opencpn. Reading and parsing XML is straightforward with wxWidgets, so I have a starting hook.

Initial plan of attack and proof of concept(simplified): Export a track from opencpn as GPX. Convert to KML. Validate on GE. Write code. Import this track KML to opencpn as overlay. Compare to original track. If all goes well, then...

The next use I have in mind is to generate intermediate KML files from GRIB data as part of the GRIB effort. These intermediate files will then be loaded into opencpn as semi-transparent overlays.

Of course, as a side benefit, these GRIB->KML files could be read in Google Earth, as well. Seems like a useful thing. Maybe I'm not the only one working on this particular path....

As you have found, symbology is a big part of the effort. Yellow pushpins rendered by GE for points are cute, but we need waypoint icons, wind barbs, shoreline markups, supplemental soundings, etc., etc. All the basic symbology info will need to be incorporated into opencpn, with reasonable defaults for unrecognized features.

And then there is whole area of user-entered chart markups (soundings, new shoreline constructions, observed phenomena, etc. All this could/should be stored and shared as KML.


Anyway, that's my roadmap. In jello...

The reverse idea that you are working on (ENC->KML->GE) is neat too. Not too sure about realtime navigation using GE, though. Its a great planning and visualization tool. Love those oblique views

And, just to fully close the loop, eventually there will be no reason not to load KMLs generated by your efforts into opencpn. For instance, if we want customized ENCs for particular lat/lon regions, etc...

Sure is fun....

Dave


Dave

[manimaul]

Originally Posted by bdbcat

As you have found, symbology is a big part of the effort. Yellow pushpins rendered by GE for points are cute, but we need waypoint icons, wind barbs, shoreline markups, supplemental soundings, etc., etc. All the basic symbology info will need to be incorporated into opencpn, with reasonable defaults for unrecognized features.

Symbology and visual representation is definitely a time consuming part. I can definitely help with any symbology for both kml and grib display. Just let me know what you need.

As for converting track and route gpx to valid kml... this can be done with gdal. The kml generated is pretty raw (pushpins and red line)
example:

ogr2ogr -f KML testroute.kml testroute.gpx

I'm extremely curious how close cm93 is to s57. I would like to use the s57 driver in gdal to convert cm93 charts to kml also.

For now, I'm working steadily on bringing all the major features of s57 to a reasonable kml display.

You might enjoy a screenshot of some progress in the s57 to kml front: