dive site handling

Davide DB dbdavide at gmail.com
Fri Mar 1 06:16:07 PST 2019


Sorry to be late to the party.

I was one strong supporter of the dive site handling and the taxonomy
features. Unfortunately things became very complicated soon and I was
shy to even mention the topic :) Even online taxonomy services gave
unpredictable results in different part of the world. I'm happy Dirk
resurrected this topic. Now I think Henrick's idea is the best place
to start.

On Wed, 27 Feb 2019 at 07:05, Linus Torvalds
<torvalds at linux-foundation.org> wrote:
>
> On Tue, Feb 26, 2019 at 1:18 AM Pedro Neves <nevesdiver at gmail.com> wrote:
> >
> > On 25/02/19 21:53, Linus Torvalds wrote:
> > >
> > > There _have_ been noises about people doing gps buoys, but honestly,
> > > that sounds a bit theoretical.
> >
> > I guess there's always a Subsurface user for every conceivable case ;-)

Here I am!

> > I do, on several occasions, record our GPS track for some of our dives,
> > particularly when doing habitat mapping. What we do is tow a surface
> > marker buoy on which a GPS receiver/logger is placed. Despite the angle
> > of the cable that connects the SMB to the scooter/diver, this works
> > really well for depths down to 25/30 m...
> >
> > We then use the GPS tracks to georeference pictures, videos and other
> > observations. So yes, I'm up for assigning a GPS track to the dives...
>
> Oh well. So much for "theoretical".
>
> I guess we should make the GPS location data simply be an "event"
> among others.  That would make it possible to show any path, and the
> Garmin Descent case would just become "add event for beginning/end".
>
> The only problem there is that once you make that kind of change, then
> older versions of subsurface won't understand it. The advantage of the
> "extradata" field was that it was already basically free-form.
>
> Of course, if the gps information is an "event" thing, then it would
> be per-dive-computer (like the "extradata" thing already is), and that
> in turn means that the GPS buoy would logically have to be treated
> like a dive computer, instead of being merged with some existing
> computer.
>
> That sounds like a nightmare too.

I'm the prince of corner cases...

Just for the sake of clarity:
I've dozen of dive related GPS tracks. Usually we use a random GPS
device and a bit of creativity exploring open sea shoals (with no
obvious underwater references) or mapping artifacts on sea bottom.
In order to reduce the drag I use a free diving marker, a spool and a
thin dyneema line tied to my scooter. I attach the GPS device to the
free diving marker, I press start and dive!
As tracking device, sometimes I used my smartphone inside a waterproof
transparent case (those used to protect the phone o a beach or for
running) and OsmAnd Android app. Other times I simply used a Garmin
running watch. In both cases it's fundamental being able to export the
gps track as gpx or kml and then having fun in Google Earth.
This method is ok only for shallow dives (up 60/70 m). Deeper I prefer
just mark the POI deploying small SMBs from the bottom.

This is what I got mapping some underwater pipes from a beach:

https://drive.google.com/open?id=1JlFWc1v0lxJtjIl_yDw118JMXHdyDJdf&usp=sharing

Right now I have all my tracks saved on my google account and a short
link into the note field inside Subsurface. I think this is the best
option.

Bye
-- 
Davide
https://vimeo.com/bocio/videos


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