Thursday, July 31, 2014

Low Cost Sidescan for Eelgrass Mapping?

We're trying to map eelgrass in shallow water.  This has been an instrument challenge for years (decades?) that has required experimentation.  Aerial methods are great, but costly.  Remote control aerial is something we're interested in, but we don't have the proper licensing yet.  Processing might still be a real hurdle with aerial photographs too.  So we're focusing on vessel-mounted systems that can be deployed rapidly with data collection tools that result in data that needs minimal processing, or at least a workflow that can be standardized and result in maps in a matter of a day or two.

Most recently we've been using a Biosonics DT-X on a small boat.  Vessel draft and maneuverability is still a concern in shallow waters that frequently have obstructions, especially rocks.  So now we're testing a jet ski, on loan from colleagues in Maine.  Our plan was to mount the Biosonics on that, but our trial run with the jet ski made us realize just how wet it is.  To use the Biosonics, we would have to do some pretty involved retrofitting to have the necessary ruggedness.  If the jet ski proves to be a reliable platform, we might put the effort into the retrofit since we like the almost non-existent processing required of the Biosonics data.  In the meantime, a colleague here at DMF, Mike Bednarski, showed me his Humminbird 698SI.  So we'll take that out and see what sort of eelgrass mapping we can do with it mounted on the jetski.

Here's the whole unit -- transducer, processing unit, and storage (SD card).

Color Palette
Here's an image from the Humminbird website.

We'll be out in a couple of weeks to see if we can image eelgrass and mooring scars in eelgrass.  Some folks at the USFWS have put together some great descriptions and details about how they use their Humminbird for habitat mapping here.

Thanks Mike!

Wednesday, July 30, 2014

Great description of sidescan sonar

Humminbird's website has a nice overview including a great video explaining what sidescan sonar is and how to read a sidescan record.

The website is here.
The link is on the website, or you can access it here.

Monday, March 31, 2014

WorldWide Telescope

I attended a science fair for kids at Harvard over the weekend. I'm not sure who had more fun, me or them, but we definitely took different things out of it.  They were pretty excited to run up and down the stairs in a big lecture hall.  I was impressed with the WorldWide Telescope, among other things.

Harvard's Alyssa Goodman gave an engaging presentation where she flew us through a 3D map of the universe.  Did you know you can barely see Earth from the sun it's so tiny?  (Of course you did!  But it's still helpful to "see" that!)  The software program is called WorldWide Telescope.  Setting it up is not as simple as Google Earth and has required a few downloads of other things along the way.  And now that it's up, it appears to be dominating my computer and network.

But it's pretty amazing.  Just exploring the scale of the universe is impressive.  It takes a LONG time to zoom out from the Earth to the sun to the galaxy...fortunately there are a host of navigation tools that work efficiently and are intuitive.

Here's an unimpressive shot of the sun at the center with teeny little planets orbiting around it.

Plus you can go see planets in our solar system and zoom to other galaxies to see pictures of them from various telescopes.

For you mapheads out there, this is a good one.

Wednesday, August 28, 2013


Sometimes it's hard to explain not only what CMECS is (a classification) but also why it matters.  Here's a funny approach to that:

Friday, May 24, 2013

From Sensor to Sound Decisions

Article in ArcNews:

From Sensor to Sound Decisions

Federal Agencies Use Sonar, Lidar, Optical Imagery to Preserve Seafloor Habitats