Aerial Photogrammetry

[Ray Timm]

Keven,
A paper you may want to look at:  Kowalski, K.P. and D.A. Wilcox. 1999. Use 
of historical and geospatial data to guide the restoration of a Lake Erie 
coastal marsh. Wetlands 19: 4.  Pages 858 - 868.  The authors are USGS out 
of Ann Arbor, and are very approachable.  Kurt (kurt_kowalski at usgs.gov ) 
would love to talk with you, I'm sure.  In his study, he tackled many of 
the issues that you are facing now.
Hope this helps.
R

Ray Timm
362D Fisheries Sciences Building
University of Washington
School of Fisheries
raytimm at u.washington.edu
206/221-6885


-----Original Message-----
From:	Keven Bennett
Sent:	Thursday, April 13, 2000 10:47 PM
To:	UW - GIS Discussion & Support
Subject:	Aerial Photogrammetry

        Hello,
        I am developing a methodology for ground truthing geodata for
ONRC to assist an interagency Spartina management group at Willapa bay.
I can obtain 1:12k color aerial photography for this area that is fairly
recent.
        I have several questions, and if anyone can point me in the
right direction, I would appreciate it greatly!
        What is the size of the smallest feature that can be expected to
be seen in these stereophoto sets?  The provider  describes them as
'exceptional' (yes, subjective, but...) and any kind of ballpark
approximation would help.
        In preperation for converting to digital data, they will need to
be scanned.  I have heard that photo quality scanning is possible with
the newest true color scanners, and I am also postive this process will
create potentially huge files (not a problem--we may work with these
serially).  What issues do I need to address here?  What output image
format is best for the follow up geoprocessing work?
        We would like to resample the image and have available ERDAS
Imagine software for the image processing and registration to already
existing geodata.  Should we resample the image with a cell size the
same as the smallest visible feature (we want to be able to retain the
data at the largest possible scale)?  What issues do we need to address
here?

        Keven Bennett
        ONRC GIS