create_surf(handles)

function handles = create_surf(handles)


area_data = handles.data.area_data;

if isfield(handles.data, 'h_surf');
    % If the ribbon plots have already been created, this function is just
    % being called to set the visibility because the user has moved the
    % slider bar.  Set the visibility of the layers according to the 
    % settings on the slider bar and checkbox
    cur_layer_val = round(get(handles.scrollLayer,'Value'));
    if get(handles.chkShowLayerOnly,'Value') == 1
        vis_ind = cur_layer_val;
    else
        vis_ind = 1:cur_layer_val;
    end
    set(handles.data.h_surf,'Visible','off');
    set(handles.data.h_surf(vis_ind,:),'Visible','on');

else
        
    % Set up surface plotting base grids
    x = (1:size(area_data,1))';
    y = (1:size(area_data,3));
    [x,y] = meshgrid(x,y);
    x = x';
    y = y';
    %xi = 1:0.5:size(area_data,1);
    xi = 1:size(area_data,1);
    %yi = 1:0.5:size(area_data,3);
    yi = 1:size(area_data,3);
    [XI,YI] = meshgrid(xi,yi);
    
    % Select the top axes
    axes(handles.ax3D);
    cla
    
%     cc = ones(size(XI));
    
    for cur_layer = 1:size(area_data,2)
        z = reshape(area_data(:,cur_layer,:),size(area_data,1),size(area_data,3));
        
        if cur_layer > 1
            % The line below is included to space the surfaces verticallyslightly
            % This is done so that data points that actually touch do not
            % "corrupt" the surfaces. It isn't strictly correct to do this,
            % but it makes the surfaces look much better
            z(z == 0) = 70;
            
            z = z + z_last;
        end
        
        z_last = z;
        
        ZI = griddata(x,y,z,XI,YI);
        
        xp = XI(1,:);
        zp = ZI';
        
        % Create the ribbon plot
        h_surf(cur_layer,:) = ribbon(xp,zp);
        set(h_surf(cur_layer,:),'CData',cur_layer*ones(size(zp,1),2));

        
        hold on;
    end

    % Turn off the black edge of the ribbon plots
    set(h_surf,'edgecolor','none');
    
    set(h_surf,'SpecularColorReflectance',0.3)
    
    % Add lighting
    light('Position',[1 1 0.2],'Style','infinite');
    lighting phong
    
    ylim(handles.ax3D,[0 48])
    set(handles.ax3D,'YTick',[0:4:48]);
    set(handles.ax3D,'XTick',[1:size(area_data,2)]);
    set(handles.ax3D,'XtickLabel',1:size(area_data,3));
    set(handles.ax3D,'XtickLabel',handles.data.disp_dates);
    set(handles.ax3D,'fontsize',8);
    zlabel('MW')
    view(37.5,30)
    axis tight
    
    handles.data.h_surf = h_surf;
    
    
    % Create day slider plane
    x_p = repmat(1,4,1);
    y_p = [1 48 48 1];
    z_max = max(max(z));
    z_p = [0 0 z_max z_max];
    
    handles.data.h_day_slider = patch(x_p,y_p,z_p,[0.5 0.5 0.5],'FaceAlpha',0.2);
    
    % Create period slider plane
    x_p = [1 size(area_data,3) size(area_data,3) 1];
    y_p = repmat(1,4,1);
%     z_max = max(max(z));
    
    handles.data.h_period_slider = patch(x_p,y_p,z_p,[0.5 0.5 0.5],'FaceAlpha',0.2);
    
    set(handles.ax3D,'climmode','manual')
    
end