OpenStreetMap
I wondered if there was any interest in adding marine features to OSM, or if there was a more appropriate equivalent ("openmarinechart" ??).
I have done some charting of small areas (too shallow/small to be of interest to commercial vessels) but there had been no way to share the data, or even to get it into my GPS as a map (MapDekode to Garmin, ugh!). Generally it's readings from an echosounder, hopefully corrected to Low Water by accounting for tides and transducer depth. I used manual entry, but I presume there are automatic solutions. In OSM, I guess one could add a spot depth as a point with appropriate attributes (units, datum, value)
I also wondered about generating terrain maps from GPS elevation data; there must be quite a lot of user data available now.
Discussion
Comment from HannesHH on 11 August 2009 at 06:23
http://openseamap.org/
It's currently the image of the week in the Wiki: http://wiki.openstreetmap.org/ ;)
Comment from burto on 11 August 2009 at 09:42
Support for marine POIs is just becoming available in mkgmap so in the future
you should be able to generate Garmin marine maps directly from OSM data.
Comment from alv on 11 August 2009 at 13:11
Do check if it applies in your country: some countries have made "systematic" depth measurements a licensed activity; they consider the data too interesting for hostile army vessels and want to keep some navigable waters a secret - thus the licensed surveyors need to present their data for "cleanup". But if they can't know who you are...
Someone did experiment with generating terrain data from a pile of gpx logs elevation data. I got the impression that only after tens of traces for each road the values start to converge to a reasonable presentation, i.e. without nonexistent hills or cliffs. And only for that road. Sorry, no link at hand.
Comment from POHB on 11 August 2009 at 13:30
I played with producing 3D images from traces I made while skiing. While they looked OK individually, several days traces contradicted each other about the height. This was with a Vista Hcx which has a barometric altimeter as well as GPS altitude.
Comment from cantece on 11 August 2009 at 13:34
Hello,
look what they have done here:
http://www.freietonne.de/seekarte/?zoom=12&lat=54.4486&lon=10.30917&layers=B00T
Cantece
Comment from Skippern on 12 August 2009 at 10:40
You can also help out with looking at Marine Mapping and the marine-tagging proposal. I have had an idea of harvesting ecco sounder data to build a sort of SRTM data source for depths, but havn't got the idea further than random thoughts.
-A