Bob has prompted me to contribute as folows:
Our SMR makes extensive use of ArcView and I see there is huge potential in
GIS to do much more than we currently manage.
However, perhaps I have missed a point somewhere? The most useful aspect of
the GIS is its capacity to store and display polygons. Unfortunately most
of our data is still represented by points - plotted grid references. This
is a legacy from our development from card index to database but we need to
move beyond this stage as soon as possible. If we are dealing with
polygons, what sort of symbols are we talking about? While we certainly
want a useful, common language that is easily recognised and understood by
all, those demanding standard 'symbologies' need to be very clear about what
the objective is and why people should adopt the standards.
I certainly don't support a standard data structure - this seems to me to
have more potential for restricting innovation and imaginative systems
development than any positive benefit. What matters is the product not the
process.
Bob says,
"There are some challenges in the database design process - notably, how to
render features with ambiguous geometries, or at different scales. Is a
triumphal arch a point feature or an area feature? Is a long narrow shell
midden a line, an area, or a point? What if the midden was recorded in 1940
as a circle on a map of the coastline?"
All these are area features and can be represented as polygons. Designated
areas (listed buildings, scheduled monuments) are defined, but beyond this,
to some extent, all archaeological sites and features have ambiguous
boundaries. Surely we just need a field in the theme table that indicates
an ambiguity value, just as we and others are currently implementing with
our point data. Users could be provided with a scale from 1 to 10 (say)
which provided an assessment of the polygon's accuracy. Different scales
should not be a problem with a GIS!
Are we in danger of seeing problems where none really exist?
John Wood
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John Wood
Senior Archaeologist
Planning and Development Service
The Highland Council
Glenurquhart Road
Inverness IV3 5NX
Tel: 01463 702502 Fax: 01463 702298
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Web: <http://www.higharch.demon.co.uk>
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