Draw GPS elevation data

The ups and downs of my bike ride to Goldsmiths visualised in Processing, I generated the GPS data here: 
http://www.geoplaner.com/    
a very useful site. My code below:



/*put the text file generated by convertGps.pde 
into the data file for this sketch. Visualises elevations (heights) on my journey to Goldsmiths. 

Ignore the x data in this version which was adapted from my earlier program
 Dare 2012 */

float[] as, lon, lat;
float x, y;
int index;
ArrayList thatXPos = new ArrayList(); //array for X
ArrayList thatYPos = new ArrayList(); //array for Y
//y in this case is elevation data
float lonMax, lonMin, latMax, latMin; //to be our min and max values

void setup() {
  // noLoop();
  size(250, 220);
  as = float(loadStrings("cleanfile.txt")); /*create this file in 'convertGPS.pde */
  background(0);
}


void draw() {
  // background(255);
  println(mouseX);
  ///you might have to adjust start and ends but this seems to work
  for (int i =0;i<as.length-2;i+=2) { //all the longitude every 3rd
    thatXPos.add(as[i]);
  }

  ///you might have to adjust start and ends but this seems to work
  for (int i =1;i<as.length-1;i+=2) { //all the  Y latitude
    thatYPos.add(as[i]);
  }


  int len = thatXPos.size();
  int len2 = thatYPos.size();
  Float[] fa = new Float[len];
  Float[] fa2 = new Float[len2];
  float[] xPosCount = new float[len];
  float[] yPosCount = new float[len2];
  thatXPos.toArray(fa);
  thatYPos.toArray(fa2);


  for (int i =0;i< len; i++) {

    xPosCount[i] = fa[i];
  }

  for (int i =0;i< len2; i++) {

    yPosCount[i] = fa2[i];
  }



  lonMax =max(xPosCount);
  lonMin =min(xPosCount);




  latMax =max(yPosCount);
  latMin =min(yPosCount);

  /*  fill(255);
   text(lonMax, 10, 30);
   text(lonMin, 10, 50);
   text(latMax, 180, 30);
   text(latMin, 180, 50);
   */


  // for (int i = 0; i < len; i++) {
  if (index < len) {
    x =xPosCount[index];
    y =yPosCount[index];
    //println("lat:  "+xPosCount[i] + "lon: "+yPosCount[i]*-1);

    //use the minimums and maximums to calculate map()
    float x1= map(x, lonMin, lonMax, 50, width-50);
    float y2= map(y, latMin, latMax, 50, height-50);

    fill(255, 0, 0, 240);

    stroke(255, 0, 0);
    line(index*5, height, index*5, height-y2);

    // point( x1, y2);
    // println("lat:  "+x1 + "lon: "+y2);
  }

  index = index +1;
}


void mousePressed() {

  save("elevation.gif");
}

//end