context.beginPath();
// Make sure to start in the right place
context.moveTo(0, canvas.height-elevations[i]);
// Skip the first point, we already started there
for (var i = 1; i < elevations.length; i++){
    //Plot the lines
    context.lineTo(i*canvas.width/elevations.length, canvas.height-elevations[i]);
}
// Move one pixel outside the right hand bottom corner of the cavas
context.moveTo(canvas.width+1, canvas.height+1);
// Move one pixel outside the left hand bottom corner of the canvas
context.moveTo(-1, canvas.height+1);
// Close the shape
context.closePath();
//Fill the shape
context.fillStyle = "#F00";
context.fill();
alert("attempting to fill");