patching fields onto an ortho background

[Rebecca Scheckler]

                                                                I need to creat
e maps of farms where the fields are colored
according to crop and everything patched back together with an
orthographic background. The way I have done this is to reclass and mask
the fields and background separately and then patch them all together. 
This works except that I lose resolution in the ortho background and do
not get the entire range of gray scale that I want.  That result makes
sense since I have reclassed the background to fewer categories.  Has
anyone figured a way of doing this without losing the detail of the ortho
image?  I would greatly appreciate seeing some sample code if you have
succeeded in this task
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  Rebecca Scheckler                        rebecca at vt.edu
  Information Systems and Insect Studies   phone: 703-231-7216          
  Virginia Tech                            fax: 703-231-9131
  202 Price Hall                           
  Blacksburg, VA 24061-0319               
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