Original Question:
We have some archaeological probability zones in Georeferenced TIFF format.
Is there a way of vectorizing the raster image data to come up with a
polygon coverage for these zones. Any help will be appreciated.
Thanks to:
Bob Ballard, Greg Harwell, Kevin Opitz, Alex Diamond, Greg Cocks and all the
others who responded.

The responses were varied depending on the resources available to us and
amount of data to be converted:
1) Using Spatial Analyst to perform the raster to feature conversion.
2) Using various other stand-alone software to convert the data like R2V
from Rockwave
   ( http://www.rockware.com/catalog/pages/r2v.html), WinTopo
(www.wintop.com)
3) The ArcView extension Feature Analyst from VLS (http://www.vls-inc.com/)
4) Digitzing the data if the data to be converted was not much.
         All these(including the Spatial Analyst for 8.0) have free trial
periods so you can try them out and see how they compare.

What we ended up doing:
I tried most of the extensions and almost all of them do a good job
converting the data. But our problem was that the probability zones were
sketched on topo sheets and had a lot of data that we did not need after the
conversion. Also since the scanned TIFFS were all the same color it was not
possible to extract the layer based on its hue(as suggested by Greg)
Since the area we needed was not too large and cleaning up the converted
vector data would be a tedious exercise we decided to just digitize the data
using Microstation and also a handy data editing extension developed by the
Massachusetts Dept. of Env. Management
(http://www.state.ma.us/dem/programs/gis/de_intro.htm)

Thanks listers!

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Rafey Subhani
Project Engineer
Gannett Fleming, Inc.
Seton Business Park
Suite A, 4701 Mt. Hope Dr.
Baltimore, MD 21215
Tel: (410)585-1460 Ext: 305
Fax: (410)585-1470
mailto: rsubhani@gfnet.com