Not sure who the respondent is doing work in Florida, but not everyone in
Florida finds aerials to not be useful in canopied areas. I, for one, use
aerials daily for survey work. They are used as basemaps to display GPS data
collected or for use with GIS data so that an understanding of the landscape can be
easily seen. As far as canopy, distinction between vegetative groupings is
often very useful, historic homesites for example often have distinctive
plantings and arrangements of canopy, and vegetative signatures are also known
(especially where the person responding-Dan- says he does work...) In South Florida,
tropical hardwoods can be delineated with available 1 and 1/2 foot true color
aerials. These hardwoods are readily associated with shell middens and so
can be used as a way of remotely locating prehistoric sites.
Knowing the limitations, resolutions, etc. of aerials is the important thing.
Rather than using aerials in some instances it might be more appropriate to
use landcover data, where analytical queries can be done in a GIS to select
for certain vegetation signatures known to be associated with certain types of
sites. As for the topo data that the Florida person-Dan- refers to as
available only in South Florida, it is actually available for the entire state, and at
much finer scales than previously mentioned. In some regions, lidar data
(done for floodplain delineation) is available through water management districts
and ACOE and provides extremely good topographic understanding of areas.
Digital terrain models are also readily available for ArcGIS users from a variety
of sources, and are free for the download. I think that we should be
cautious of discounting technologies, when using better analysis techniques (more
than just 'looking' at maps and aerials), might be able to readily discern
features and sites. If we just say that the aerials in and of themselves are not
very useful, we might not be very receptive to someone who says that in fact
they are extremely useful. It is not so much the limitation of the aerials as it
is the limitations of the reading of the aerials, and someone familiar with
interpretation and use of these in GIS and RS programs can tease out detail that
could be otherwise overlooked.
If anyone would like sources for data or other suggestions for aerial use,
feel free to write me off list.
Best,
Lori
Lori D. Collins, M.A.
Instructor/Undergraduate Advisor
University of South Florida
Department of Anthropology
813.974.0783
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