The vertical scale.
Value type: Object
 start - (float) the mininum scale value
 
 end - (float) the maximum scale value
 
 step - (float) the scale step
 
 template - (string or function) the template for scale markers. By default, it is defined by the 'start', 'step' and 'end' attributes
 
 lineShape - ('line' and 'arc') the type of lines. By default, 'line'
 
 lineColor - (string) the color of scale arcs. By default, '#cfcfcf'
 
var chart =  new dhtmlXChart({
     yAxis:{
	lineShape:"arc"
     },
     ...
})