Name: build_trace_mosaic

   Purpose: generate TRACE mosaic map, optionally -> WWW

   Input Parameters:
      index, data  - from read_trace, preselected mosic images
      
   Output Parameters:
  
   Keyword Parameters:
      www   - if set, make an WWW version
      csize - composite size (default=1024)  
      fov   - solar FOV in arcminutes - default=40 = full sun/above limb
      autocolor - if set, apply wavelenght dependent color table (ssw_ct2rgb)
      title - optional user defined title
      nogrid - if set, inhibit solar/limb grid
      pixmap - if set, build mosaic in off screen PIXMAP
      zbuffer - if set, build mosaic in Z-buffer  
  
   Calling Seqeunce:
     [select, procss, and scale your 'data' (mosaic cube) as desired, then...]
     IDL> trace_build_mosiac, index, data [,csize=xxxx, fov=xx, title="title" ,/www

   Method:
      index2map and then apply DMZarro mapping SW to position/composite

   Restrictions:
     need index,data with SSW standards (ex: read_trace default output)
     need at least one SOHO instrument in  SSW path  
  
   History:
      28-April-1998 - S.L.Freeland - apply SSW/Mapping techniques to TRACE