- Hey guys, this is Jeff.
I'm here with Evan.
Evan, what're we doing today?
- Today we're out here
at Cane Bay to take some
pictures and measurements
of one of the anchors
out here to make a cool 3D model.
- So today, we're going
to get under the water
and we're going to show you
how to make this happen.
So, it's really cool.
We've got to take a lot of pictures
and we've got to take
a lot of measurements,
and we're going to stitch together
this model afterwards.
So stick with us through
the end of the video
and if you like what you see,
make sure to subscribe.
All right, let's go diving.
(dramatic music)
So Cane Bay out here on the north shore
of St. Croix, has dozens
and dozens of anchors.
They all date back to
the seventh to nineteenth
centuries, and they're
really historical artifacts.
Today, we're going to go find one that's
in the shallow water.
It's about twenty feet deep.
It's one that's probably rarely visited.
Not many divers go over there.
It's a little bit to the east
of the main dive site,
out in front of a restaurant
called Off the Wall.
And so we're headed out there.
We're going to mark it with GPS.
We've got one of those with us today
in our four inch float here.
We're also got some
measuring tape with us today,
so we're going to measure the different
dimensions of the anchor,
and then we're going to take a
probably about 100-200
photographs of it as well,
all around and over the top of it
and stitch those back
together once we're on shore
and do a 3D model using photogrammetry
and some fancy software.
All right, while swimming
along the surface
of the anchor we're
looking for, we came across
another one here.
This one is pretty well
buried in the corral,
but the ring and the shank are really,
are really exposed, so
let's check that out
real quick.
We've made it to our anchor site,
and we're going to throw our own anchor
overboard here and mark our spot.
(acoustic music)
Okay, so just to give a quick tour
of the anchor here.
It looks like it dates back
to the seventeenth to
the nineteenth century.
It's been down here for quite some time.
It doesn't have a stock on it.
A stock is a bar that kind
of would be vertical here
at the top where the ring is.
There was probably one,
but rotted away long ago.
We've got a pretty good size ring to it.
It's got a long arm down here.
This was probably a bower
anchor for a small ship
or maybe a secondary
anchor for a larger one.
But considering that we're only in,
what are we,
21 feet of water, this is probably
a bower anchor for a small ship.
The draft here is pretty shallow
for anything larger.
(acoustic music)
- [Jeff] While we're taking pictures
to create our 3D model,
we have to take them
very close together, about 70-80% overlap
of the previous picture.
Only this way can the software kind of
stitch the images together
so they can create that model
using photogrammetry.
We also have to go all the way around
the object here,
and we're just going to
keep taking these images
over and over again from every angle,
from the sides to the top.
Really get that full model,
you want to get every,
every inch of the anchor
here so that that model
comes out when we run
it through the software.
(acoustic music)
So, really successful dive today.
We got all the pictures that we need.
We took dozens of measurements as well
of the anchor.
So what we're going to do now is pack up
and head back, and tonight we're going to
run all those images
through some software,
and it's going to probably take 8-12 hours
to, you know, stitch all
those image together to
create a model, but
through the magic of video
we're just going to bring
that straight to you.
So, let's check it out.
All right, we are in
our home office today,
and overnight we processed
all the that images we took.
In total, it was about 198 images,
and we ran it through a
software called Metashape.
It's by a company called Agisoft.
We don't have any affiliation with them,
but they make amazing software
for doing photogrammetry.
We've got a link to them
in the description below,
so totally check them out.
But, at any rate, let's take a look
at what we did overnight.
So the first thing we did is we loaded
all those photos into the software package
and ran it through the workflow.
So we can take look
and see the photos here
are all the little blue
triangles with the images
over them.
It's every photo kind of
aligned in its position
in the water column from
where we took it above
or around the anchor.
So, it's extrapolated all those data
into different points underneath,
and so if we clear the images real quick,
we can take a look at those points.
Okay, so hiding the
images gets us this point,
and we can see that the anchor is actually
starting to take shape a little bit here.
So, the next thing we
need to do is kind of
tie all those points
together into a wire mesh.
So were going to create that.
Okay, so we've got our wire mesh here.
We can really see the shape of our anchor
starting to come together
with the big long shank here
and our ring on the end
as well as these big arms
that were there with the palms.
If we rotate this
around, we can really see
that there's a lot of
detail in there as well.
So the next step is to then overlay this
with all the image data
for colors and textures.
So let's go ahead and to that.
All right.
So we've got all our
colors and textures here,
and I'm just going to move the object up
real quick.
Our anchor here is
rotated around so we can
get a better look at the whole thing here.
So we can now really see
that it looks exactly
like the anchor that we saw yesterday
and were diving on.
So if we just kind of rotate
this all the way around
we can see every aspect of it.
So really a great documentation tool.
Love it, absolutely love it.
So you may be wondering
what were we going to do
with all this data?
Obviously yesterday we
spent a lot of time diving,
measuring, taking lots of
photographs, lots of video.
We created our model here.
We've also got the GPS coordinates.
So we've really got
everything we need to know
about this anchor and its location.
And so we want to share
that and make it public.
So we're doing two things.
One is we're going to send
it off as a big package
to the U.S. Virgin Islands State Historic
Preservation office, and
hopefully they'll include it
in their inventory there.
And then second, there's
a project called the
Big Anchor Project.
You can check their website out at
biganchorproject.com
But that's a project done by
the Nautical Archeology Society
in the United Kingdom, and they have
a big database online of different anchors
around the world, so
it's a global project.
On their website, you
can see different ways on
how to document and map anchors.
They've got a lot of
information out there.
Great resource.
So we're going to contribute our data
to their project as
well so it can be shared
out there, so check that out.
So we're always learning,
so you know if you guys
have any comments, suggestions, tips,
put them in the comments
below on photogrammetry
or the anchors or documenting
or sharing the data
or really anything.
Love to hear from you,
and if you're not yet a
subscriber, go ahead and
hit that subscribe button.
Hit the little bell
notification next to it,
that way you'll never miss a dive.
And we try to spend a
lot of time in the water
and bring it to you, so
we want to share it all.
But until next time, stay
safe and keep diving.
(acoustic music)
