nxmin=conductor_data(conductor)%nxmin
    nxmax=conductor_data(conductor)%nxmax
    nymin=conductor_data(conductor)%nymin
    nymax=conductor_data(conductor)%nymax
    
    layer_number=0
      
    if (conductor_data(conductor)%mesh_to_layer_type.EQ.1) then
! each marked cell in the grid becomes a layer and hence a segment
    
      do ix=nxmin,nxmax
        do iy=nymin,nymax
          
          if ( conductor_data(conductor)%grid(ix,iy).EQ.1 ) then
    
            layer_number=layer_number+1
      
            apx=conductor_data(conductor)%xc+real(ix)*conductor_data(conductor)%dl
            apy=conductor_data(conductor)%yc+real(iy)*conductor_data(conductor)%dl
    
            conductor_data(conductor)%x(layer_number)=apx
            conductor_data(conductor)%y(layer_number)=apy
            conductor_data(conductor)%w(layer_number)=conductor_data(conductor)%dl
            conductor_data(conductor)%h(layer_number)=conductor_data(conductor)%dl
              
            conductor_data(conductor)%d(layer_number)=0.0
            conductor_data(conductor)%anwinc(layer_number)=conductor_data(conductor)%nwinc
            conductor_data(conductor)%anhinc(layer_number)=conductor_data(conductor)%nwinc
              
          end if
        end do
      end do

    else if (conductor_data(conductor)%mesh_to_layer_type.EQ.2) then
    
! each row of cells in the grid becomes a segment
      do iy=nymin,nymax
    
        in_conductor=.FALSE.
        cx1=0
        cx2=0
      
        do ix=nxmin,nxmax
      
          if ( (.NOT.in_conductor).AND.(conductor_data(conductor)%grid(ix,iy).EQ.1) ) then
    
! we have moved from air to conductor so save this x cell number
             cx1=ix
             in_conductor=.TRUE.
       
           else if ( (in_conductor).AND.(conductor_data(conductor)%grid(ix,iy).EQ.0) ) then
! we have moved from conductor to air so create a layer for this region

             cx2=ix-1
             in_conductor=.FALSE.
       
             layer_number=layer_number+1
         
             cw=real(cx2-cx1+1)*conductor_data(conductor)%dl
             ch=conductor_data(conductor)%dl
       
             apx=conductor_data(conductor)%xc+real(cx2+cx1)/2.0
             apy=conductor_data(conductor)%yc+real(iy)*conductor_data(conductor)%dl
    
             conductor_data(conductor)%x(layer_number)=apx
             conductor_data(conductor)%y(layer_number)=apy
             conductor_data(conductor)%w(layer_number)=cw
             conductor_data(conductor)%h(layer_number)=ch
               
             conductor_data(conductor)%d(layer_number)=0.0
             conductor_data(conductor)%anwinc(layer_number)=conductor_data(conductor)%nwinc
             conductor_data(conductor)%anhinc(layer_number)=conductor_data(conductor)%nwinc

             cx1=0
             cx2=0
             
          end if
    
        end do ! next col

      end do ! next row   

    else if (conductor_data(conductor)%mesh_to_layer_type.EQ.3) then

! specific process for cylinders...    
! First find the central square region
      found_square=.FALSE.
      do ix=0,nxmax-2
        iy=ix
                  
        if ( (conductor_data(conductor)%grid(ix,iy).EQ.1).AND.  &
             (conductor_data(conductor)%grid(ix+1,iy+1).EQ.0)) then                                            
           
          layer_number=layer_number+1
          cx1=ix
          
          cw=2d0*(real(ix)+0.5d0)*conductor_data(conductor)%dl
          ch=2d0*(real(iy)+0.5d0)*conductor_data(conductor)%dl
       
          apx=conductor_data(conductor)%xc     ! centre of circle
          apy=conductor_data(conductor)%yc
    
          conductor_data(conductor)%x(layer_number)=apx
          conductor_data(conductor)%y(layer_number)=apy
          conductor_data(conductor)%w(layer_number)=cw
          conductor_data(conductor)%h(layer_number)=ch
            
          conductor_data(conductor)%d(layer_number)=0.0
          
          if (conductor_data(conductor)%auto_grid_density) then
            CALL calc_nmin(conductor_data(conductor)%skin_depth,conductor_data(conductor)%w(layer_number), &
                                          conductor_data(conductor)%rw,nw_auto)
            CALL calc_nmin(conductor_data(conductor)%skin_depth,conductor_data(conductor)%h(layer_number), &
                                          conductor_data(conductor)%rh,nh_auto)
            conductor_data(conductor)%anwinc(layer_number)=nw_auto
            conductor_data(conductor)%anhinc(layer_number)=nh_auto         
          else
            conductor_data(conductor)%anwinc(layer_number)=conductor_data(conductor)%nwinc
            conductor_data(conductor)%anhinc(layer_number)=conductor_data(conductor)%nwinc
          end if
          
          found_square=.TRUE.
          EXIT                   ! leave the loop
    
        end if   ! found the corner
    
      end do ! next row
      
      if (.NOT.found_square) then
        write(*,*)'ERROR: not found central square...'
        STOP 1
      end if
      
! now search out in the x directiion adding layers
      do ix=cx1+1,nxmax
        
        do iy=0,cx1  ! search in y to find the extent of this layer
                  
          if ( (conductor_data(conductor)%grid(ix,iy).EQ.1).AND.  &
               (conductor_data(conductor)%grid(ix,iy+1).EQ.0)) then
             
! we have moved from metal to air so add four segments                                                  

! add layer on xmax side           
            layer_number=layer_number+1
         
            cw=conductor_data(conductor)%dl
            ch=2d0*real(iy+0.5d0)*conductor_data(conductor)%dl       
            apx=conductor_data(conductor)%xc+real(ix)*conductor_data(conductor)%dl
            apy=conductor_data(conductor)%yc
    
            conductor_data(conductor)%x(layer_number)=apx
            conductor_data(conductor)%y(layer_number)=apy
            conductor_data(conductor)%w(layer_number)=cw
            conductor_data(conductor)%h(layer_number)=ch
            
            conductor_data(conductor)%d(layer_number)=0.0
          
            if (conductor_data(conductor)%auto_grid_density) then
              CALL calc_nmin(conductor_data(conductor)%skin_depth,conductor_data(conductor)%w(layer_number), &
                                          conductor_data(conductor)%rw,nw_auto)
              CALL calc_nmin(conductor_data(conductor)%skin_depth,conductor_data(conductor)%h(layer_number), &
                                          conductor_data(conductor)%rh,nh_auto)
              conductor_data(conductor)%anwinc(layer_number)=nw_auto
              conductor_data(conductor)%anhinc(layer_number)=nh_auto         
            else
              conductor_data(conductor)%anwinc(layer_number)=conductor_data(conductor)%nwinc
              conductor_data(conductor)%anhinc(layer_number)=conductor_data(conductor)%nwinc
            end if

! add layer on xmin side           
            layer_number=layer_number+1
         
            cw=conductor_data(conductor)%dl
            ch=2d0*real(iy+0.5d0)*conductor_data(conductor)%dl       
            apx=conductor_data(conductor)%xc-real(ix)*conductor_data(conductor)%dl
            apy=conductor_data(conductor)%yc
    
            conductor_data(conductor)%x(layer_number)=apx
            conductor_data(conductor)%y(layer_number)=apy
            conductor_data(conductor)%w(layer_number)=cw
            conductor_data(conductor)%h(layer_number)=ch
            
            conductor_data(conductor)%d(layer_number)=0.0
            if (conductor_data(conductor)%auto_grid_density) then
              CALL calc_nmin(conductor_data(conductor)%skin_depth,conductor_data(conductor)%w(layer_number), &
                                          conductor_data(conductor)%rw,nw_auto)
              CALL calc_nmin(conductor_data(conductor)%skin_depth,conductor_data(conductor)%h(layer_number), &
                                          conductor_data(conductor)%rh,nh_auto)
              conductor_data(conductor)%anwinc(layer_number)=nw_auto
              conductor_data(conductor)%anhinc(layer_number)=nh_auto         
            else
              conductor_data(conductor)%anwinc(layer_number)=conductor_data(conductor)%nwinc
              conductor_data(conductor)%anhinc(layer_number)=conductor_data(conductor)%nwinc
            end if

! add layer on ymax side           
            layer_number=layer_number+1
         
            cw=2d0*real(iy+0.5d0)*conductor_data(conductor)%dl       
            ch=conductor_data(conductor)%dl
            apx=conductor_data(conductor)%xc
            apy=conductor_data(conductor)%yc+real(ix)*conductor_data(conductor)%dl
    
            conductor_data(conductor)%x(layer_number)=apx
            conductor_data(conductor)%y(layer_number)=apy
            conductor_data(conductor)%w(layer_number)=cw
            conductor_data(conductor)%h(layer_number)=ch
            
            conductor_data(conductor)%d(layer_number)=0.0
            if (conductor_data(conductor)%auto_grid_density) then
              CALL calc_nmin(conductor_data(conductor)%skin_depth,conductor_data(conductor)%w(layer_number), &
                                          conductor_data(conductor)%rw,nw_auto)
              CALL calc_nmin(conductor_data(conductor)%skin_depth,conductor_data(conductor)%h(layer_number), &
                                          conductor_data(conductor)%rh,nh_auto)
              conductor_data(conductor)%anwinc(layer_number)=nw_auto
              conductor_data(conductor)%anhinc(layer_number)=nh_auto         
            else
              conductor_data(conductor)%anwinc(layer_number)=conductor_data(conductor)%nwinc
              conductor_data(conductor)%anhinc(layer_number)=conductor_data(conductor)%nwinc
            end if

! add layer on ymin side           
            layer_number=layer_number+1
         
            cw=2d0*real(iy+0.5d0)*conductor_data(conductor)%dl       
            ch=conductor_data(conductor)%dl
            apx=conductor_data(conductor)%xc
            apy=conductor_data(conductor)%yc-real(ix)*conductor_data(conductor)%dl
    
            conductor_data(conductor)%x(layer_number)=apx
            conductor_data(conductor)%y(layer_number)=apy
            conductor_data(conductor)%w(layer_number)=cw
            conductor_data(conductor)%h(layer_number)=ch
            
            conductor_data(conductor)%d(layer_number)=0.0
            if (conductor_data(conductor)%auto_grid_density) then
              CALL calc_nmin(conductor_data(conductor)%skin_depth,conductor_data(conductor)%w(layer_number), &
                                          conductor_data(conductor)%rw,nw_auto)
              CALL calc_nmin(conductor_data(conductor)%skin_depth,conductor_data(conductor)%h(layer_number), &
                                          conductor_data(conductor)%rh,nh_auto)
              conductor_data(conductor)%anwinc(layer_number)=nw_auto
              conductor_data(conductor)%anhinc(layer_number)=nh_auto         
            else
              conductor_data(conductor)%anwinc(layer_number)=conductor_data(conductor)%nwinc
              conductor_data(conductor)%anhinc(layer_number)=conductor_data(conductor)%nwinc
            end if
    
            EXIT ! this layer has been set so go to the next x layer
    
          end if   ! found the corner
    
        end do ! next y
    
      end do ! next row

    else
      write(*,*)'Unknown mesh_to_layer_type:',conductor_data(conductor)%mesh_to_layer_type, &
                'in conductor',conductor
      STOP 1
    end if
    
! the number of layers may have changed if we have combined grid cells      
    conductor_data(conductor)%tot_n_layers=layer_number