AS3: Line graph is glitchy - actionscript-3

Question

Having a bit of a problem with some code I've written. Basically what it does is take 3 values that constantly change and graphs them over time in the form of a cumulative line graph. It almost works except I get this weird line drawn across the entire stage and further and I can't figure out what the issue is. The full code is below, you can run it by pasting it into flash.
import flash.display.Shape;
import flash.display.MovieClip;
import flash.display.Sprite;
import flash.utils.Timer;
var y1:Array = new Array();
var y2:Array = new Array();
var y3:Array = new Array();
var avg:Array = new Array();
var y1Shape:Shape = new Shape();
var y2Shape:Shape = new Shape();
var y3Shape:Shape = new Shape();
var avgShape:Shape = new Shape();
var container:Sprite = new Sprite();
var scale:uint = 1;
var redrawGraph:int = setInterval(reDraw,500);
var y1Int:int = 0;
var y2Int:int = 0;
var y3Int:int = 0;
container.addChild(y1Shape);
container.addChild(y2Shape);
container.addChild(y3Shape);
container.addChild(avgShape);
this.addChild(container);
function reDraw():void
{
y1Shape.graphics.clear();
y2Shape.graphics.clear();
y3Shape.graphics.clear();
avgShape.graphics.clear();
y1Shape.graphics.lineStyle(1, 0x0066FF, 1);
y1Shape.graphics.beginFill(0x0066FF, 0.5);
y2Shape.graphics.lineStyle(1, 0x009900, 1);
y2Shape.graphics.beginFill(0x009900, 0.5);
y3Shape.graphics.lineStyle(1, 0x990000, 1);
y3Shape.graphics.beginFill(0x990000, 0.5);
avgShape.graphics.lineStyle(1, 0x000000, 1);
y1Int = rand();
y2Int = rand();
y3Int = rand();
trace(y1Int, y2Int, y3Int);
y1.unshift(y1Int);
y2.unshift(y2Int);
y3.unshift(y3Int);
popOut(y1);
popOut(y2);
popOut(y3);
var i:uint,sum:uint,aLength:uint,len:uint = y1.length,max:int = 0,height_:int = 400;
scale = 10;
for (i=0; i<len; i++)
{
max = Math.max(y1[i] + y2[i] + y3[i],max);
}
for (i=0; i<len; i++)
{
sum += y1[i] + y2[i] + y3[i];
}
avg.unshift(Math.round(sum/len));
/*--------------------------------MATCHED GRAPH------------------------------------------*/
var y1_commands:Vector.<int> = new Vector.<int>();
var y1_coord:Vector.<Number>= new Vector.<Number>();
var y1_coord_rev:Vector.<Number> = new Vector.<Number>();
y1_commands.push(1);
y1_coord.push(400,height_);
for (i=0; i<len; i++)
{
y1_commands.push(2);
y1_coord.push((400-i*scale),height_-(Math.round((y1[i]/max)*height_)));
y1_coord_rev.unshift((400-i*scale),height_-(Math.round((y1[i]/max)*height_)));
}
for (i=len; i>0; i--)
{
y1_commands.push(2);
y1_coord.push(400 - i*scale,height_);
}
y1_commands.push(2);
y1_coord.push(400,height_);
/*--------------------------------MATCHED GRAPH------------------------------------------*/
/*----------------------------------BUSY GRAPH-------------------------------------------*/
var y2_commands:Vector.<int> = new Vector.<int>();
var y2_coord:Vector.<Number>= new Vector.<Number>();
var y2_coord_rev:Vector.<Number> = new Vector.<Number>();
y2_commands.push(1);
y2_coord.push(400,height_-(Math.round((y1[i]/max)*height_)));
for (i=0; i<len; i++)
{
y2_commands.push(2);
y2_coord.push((400-i*scale),height_-(Math.round(((y1[i]+y2[i])/max)*height_)));
y2_coord_rev.unshift((400-i*scale),height_-(Math.round(((y1[i]+y2[i])/max)*height_)));
}
for (i=len; i>0; i--)
{
y2_commands.push(2);
y2_coord.push(400 - i*scale, height_-(Math.round((y1[i]/max)*height_)));
}
y2_commands.push(2);
y2_coord.push(400,height_-(Math.round((y1[i]/max)*height_)));
/*----------------------------------BUSY GRAPH-------------------------------------------*/
/*----------------------------------VAC GRAPH-------------------------------------------*/
var y3_commands:Vector.<int> = new Vector.<int>();
var y3_coord:Vector.<Number>= new Vector.<Number>();
var y3_coord_rev:Vector.<Number> = new Vector.<Number>();
y3_commands.push(1);
y3_coord.push(400,height_-(Math.round(((y1[i]+y2[i])/max)*height_)));
for (i=0; i<len; i++)
{
y3_commands.push(2);
y3_coord.push((400-i*scale),height_-(Math.round(((y1[i]+y2[i]+y3[i])/max)*height_)));
y3_coord_rev.unshift((400-i*scale),height_-(Math.round(((y1[i]+y2[i]+y3[i])/max)*height_)));
}
for (i=len; i>0; i--)
{
y3_commands.push(2);
y3_coord.push(400 - i*scale, height_-(Math.round(((y1[i]+y2[i])/max)*height_)));
}
y2_commands.push(2);
y2_coord.push(400,height_-(Math.round(((y1[i]+y2[i])/max)*height_)));
/*----------------------------------BUSY GRAPH-------------------------------------------*/
//y3Shape.graphics.drawPath(y3_commands, y3_coord);
y2Shape.graphics.drawPath(y2_commands, y2_coord);
y1Shape.graphics.drawPath(y1_commands, y1_coord);
}
function popOut(a:Array):void
{
if (a.length >=Math.ceil(400/scale))
{
a.pop();
}
}
function rand():int
{
return Math.floor(Math.random() * (1 + 5 - 0) + 0);
}
y3Shape is commented out until the problem with y2Shape is fixed (having both drawn just makes the problem harder to figure out).
Any ideas what could be up?
Thanks

Answer 1

If you insert trace your vectors near .drawPath, you'll see something like that:
trace(y2_commands); // 1,2,2,2,2
trace(y2_coord); // 400,171,400,57,390,NaN,400,171,400,57
So, NaN (Not a Number) means, that you have error in coordinates calculating.
ps. y1[i] in first calculating of BUSY GRAPH is undefined

Answer 2

You seem to be using beginFill(), when you draw a path that's not looped, Flash requires your path to get looped in order to fill it with something. So, it loops it implicitly by adding a line to your starting point and filling it. In order to receive a non-overlapping path, add two points to your path that will be right below 0 point in X axis, one right under the last point on your graph, and one right under the FIRST point on the graph.
Actually, you already have them installed, but for some reason you place not 2 points, but a whole lot of em, and height position of that line is plainly wrong. Your code states:
for (i=len; i>0; i--)
{
y2_commands.push(2);
y2_coord.push(400 - i*scale, height_-(Math.round((y1[i]/max)*height_)));
}
You should have:
for (i=len; i>0; i--)
{
y2_commands.push(2);
y2_coord.push(400 - i*scale, height_);
}
Or even better:
y2_commands.push(2);
y2_commands.push(2);
y2_coord.push(400 - len*scale, height_);
y2_coord.push(400, height_);