OpenCPN and TeamSurv

[TimThornton]

TeamSurv is a project using the crowd to create better depth data for charts - you log GPS and depth data as you go about your normal activities, and then upload the data to the TeamSurv server for tidal corrections and so on. Processed data can be viewed online and also downloaded (though not yet in digital chart formats - we're working on that at the moment).

You can now log data for TeamSurv from within OPenCPN, using the VDR plugin. To see details on how to do this, see the OpenCPN entry in the Nav Software section on the TeamSurv web site.

All OpenCPN users are more than welcome to join in and contribute to TeamSurv.

[bobofthenorth]

I wouldn't mind participating and maybe I could find this out by searching your homepage but how do you deal with the limitations of my depthfinder? I've got two depthfinders onboard. One of them is accurate to about 200 feet and the other to about 600 feet but past that they are both just silly. The problem though is that either one of them is perfectly capable of getting a fix on a thermocline. So I could be cruising in 2000 feet of water with a good solid return at 50 feet. I know its BS so I don't worry about it but if its getting logged into a file how do you know its BS?
(I could just as easily be cruising in 200 feet of water with a thermocline return from 30 feet although that situation is less common. In both cases though the screen will give me enough information to know what's going on but the depthfinder will output a solid return at whatever innaccurate depth it happens to have locked onto.)

[TimThornton]

Bob,
Most of the data we have collected so far has been for coastal waters, where this isn't an issue. However I agree that in deeper waters this can be an issue, as well as the waters being too deep for the sounder and so returning a value of 0 or 999 or whatever the sounder manufacturer has programmed in. You can see this if you look at the online data for a boat that went from Malaysia to the Gulf, where the depth sounder read 0 for much of the passage.
One of the things on the to do list is to be able to filter out these values, probably by creating a global 50m set of contours and looking for rogue values on the deep side of that, but we need to get more data from boats going off the continental shelf to warrant the effort and to see the variations in depth sounder outputs first. With the data processing framework we have, we can plug in a module to do this, and it will then trigger recalculation of the affected data points automatically.
By the way, I forgot to mention in the original post that we can handle old data as well as new, we just might have to upload some older tide predictions before the old data is processed.
Tim

[jonasaberg]

Interesting project. Thanks for posting here.
I took a very quick look so I may have missed some vital info, so bare with.

How do you create charts based on/including the soundings?

I guess there is a procedure like:
-Import a picture (of the charted area)
-Calibrate it (map pixels in the image vs Lat and Long)
-Import the track with soundings (the logged soundings with positions)
-Create contour lines of depths, possibly color coded depth maps etc.

Could you describe this part, I don't find info about it on your web page. Or is this something for the future?

/J

[TimThornton]

The data processing is largely automated, and consists (in brief) of quality checking the uploaded data, correcting for tides/sea level changes, collating all the tracks in a given area and doing number crunching on them to create a variable size grid, plus various data quality measures. We then feed this in to the chart generation side to add a reference coastline, render the depths by colour, add contours, and the grid etc associated with a chart.

At present we have charts viewable online once you are registered on the site (go to View->Charts) or downloadable as PDFs (Download->Charts) , but the next iteration will also offer BSB 3 format charts that can be used in OpenCPN (we'd like to do S-57 as well but the tools are outside of our budget and we don't have the time to invest to write an S-57 generator).

You can read more about the technicalities of the project in the various documents under Downloads->Documents.