Jamaica Bay Dredge Mapping- Salt Marsh Construction

[Gena Wirth]

Hi Public Lab,

I took a balloon mapping trip out to NYC's Jamaica Bay with the Dredge
Research Collaborativ <http://dredgeresearchcollaborative.org/>e last week

and have posted a research note on the results:

http://publiclaboratory.org/notes/gwirth/7-23-2012/yellow-bar-island-dredge-reuse-and-faa-permitting

I'm wondering if anyone has experience mapping salt marshes, either
naturalized or constructed, especially in areas where tidal patterns or
constructed conditions make geo-locating and stitching difficult. There is
literally nothing to align to as this is a new island creation.  We're
trying to get drawing backgrounds from the USACE to use as a base layer for
image alignment, but in case this doesn't work out, we're looking for a
backup plan!

Also, I'm looking to chat with anyone with expertise analyzing marsh or
vegetative communities from aerial photographs as we're planning a second
round to capture the intersection of this new constructed marsh with the
intertidal island it connects to.

Cheers,

Gena

[Jeffrey Warren]

---------- Forwarded message ----------
From: "Alex Kolker" <ako...@lumcon.edu>
Date: Jul 23, 2012 5:16 PM
Subject: Re: [PLOTS] Jamaica Bay Dredge Mapping- Salt Marsh Construction
To: "Jeffrey Warren" <je...@publiclaboratory.org>
Cc: "Alex Ameen" <aam...@lumcon.edu>

I know Jamaica Bay very well! I did part of my grad work there. I'd be happy to help.

-Alex

On Mon, Jul 23, 2012 at 4:07 PM, Jeffrey Warren <je...@publiclaboratory.org> wrote:

Cool! Interesting to you folks?

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[Jeffrey Warren]

Oops, also ccing Alex Kolker who responded.

[Mathew Lippincott]

cool Gina! nice job getting a NOTAM, I'm excited to see folks successfully navigate that process. 

I don't have any suggestions for this round of imagery, but the next time you head out, consider using ground control points-- 

An intro to ground control points:

http://publiclaboratory.org/wiki/mapping-curriculum-ground-control-point-targets

Coded ground control points, for when you need to use a lot:

http://publiclaboratory.org/notes/jasja/6-13-2012/coded-ground-control-points

Chris Fastie has used party balloons as ground control points-- this might be the best option for a wetland because they're waterproof.  I also can't wait for serious scientific applications for balloon animals :) 

http://publiclaboratory.org/notes/cfastie/6-24-2012/alaska-range-balloon-mapping

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[Adam Griffith]

Hi Gina,

I've mapped marshes a bunch from boats and land.  I've done high marsh and low marsh and have looked at changes in vegetation over two field seasons.  I'd suggest trying Microsoft Image Composite editor.  It does pretty well with limited features.  If you didn't put in some GCPs (ground control points), it's a little harder.  We've used triangular fluorescent orange plastic speed squares that are exactly one foot on each side for this exact situation.  Are you mapping the intertidal area?

Best,

Adam

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[gonzoearth]

If you dont have existing imagery or ground control points it does get more difficult. Using a vector layer in overlay is totally ok. Another strategy is to take unprojected imagery from a different source and rectify it against your existing base data and then use that. This can be done to expand, update, or improve the resolution of your base data. This project began with a vector layer of the city and then high altitude imagery from an airplane was laid down before rectifying imagery from a balloon flight at lower altitude http://gigapan.com/gigapans/50074
In this case if you cannot find any kind of unprojected imagery of the site to augment your base data another strategy is to fly  at an altitude much higher than your mapping resolution, and the images will likely be easier to rectify against existing base data despite the change with the sand or seasonal vegetation. The idea is that the imagery is of such a great extent that there are enough hard feature signatures in other parts of the scene to correct the image.
Yet another perhaps more desperate tactic is to assume that the altitude and vertical angle is is consistent enough within a reasonable threshold, and then discover the scale factor of the imagery from another part of the scene where there are matching features with the base data. Finally, apply that scale factor to the rest of the set and stitch the imagery.

-Stewart 

On Monday, July 23, 2012 5:32:26 PM UTC-7, Adam Griffith wrote:

Hi Gina,

I've mapped marshes a bunch from boats and land.  I've done high marsh and low marsh and have looked at changes in vegetation over two field seasons.  I'd suggest trying Microsoft Image Composite editor.  It does pretty well with limited features.  If you didn't put in some GCPs (ground control points), it's a little harder.  We've used triangular fluorescent orange plastic speed squares that are exactly one foot on each side for this exact situation.  Are you mapping the intertidal area?

Best,

Adam

On Mon, Jul 23, 2012 at 4:10 PM, Gena Wirth <geneva...@gmail.com> wrote:

Hi Public Lab,

I took a balloon mapping trip out to NYC's Jamaica Bay with the Dredge
Research Collaborativ <http://dredgeresearchcollaborative.org/>e last week

and have posted a research note on the results:

http://publiclaboratory.org/notes/gwirth/7-23-2012/yellow-bar-island-dredge-reuse-and-faa-permitting

I'm wondering if anyone has experience mapping salt marshes, either
naturalized or constructed, especially in areas where tidal patterns or
constructed conditions make geo-locating and stitching difficult. There is
literally nothing to align to as this is a new island creation.  We're
trying to get drawing backgrounds from the USACE to use as a base layer for
image alignment, but in case this doesn't work out, we're looking for a
backup plan!

Also, I'm looking to chat with anyone with expertise analyzing marsh or
vegetative communities from aerial photographs as we're planning a second
round to capture the intersection of this new constructed marsh with the
intertidal island it connects to.

Cheers,

Gena

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