<script src="javascript/HeatmapAPI.aspx?k=d975a671-4a29-44bc-9ee1-6e1b281f52bb" type="text/javascript"></script>

<script src="http://maps.google.com/maps?file=api&v=2&key=(YOUR GOOGLE KEY HERE)" type="text/javascript"></script>

<script src="javascript/HeatmapAPIGoogle.js" type="text/javascript"></script>

<script type="text/javascript">
function loadGoogle()
{
 if (GBrowserIsCompatible())
 {
  m = new GMap2(document.getElementById("map"));
  m.addControl(new GLargeMapControl());
  m.addControl(new GMapTypeControl());
  m.setCenter(new GLatLng(39, -94.75), 11);
  initHeatmap();
 }
 else
  alert('Your Internet browser is not compatible
    with this website.');
}

setTimeout('loadGoogle()', 1);

function initHeatmap()
{
  var myHM = new GEOHeatmap();
  myHM.Init(400, 300); // Step 1
  myHM.UseURL('SampleHMReturnImage.aspx?k=0'); // Step 2
  var preUrl = myHM.GetURL();
  var heatmapOverlay = new HMGoogleOverlay(preUrl);
  m.addOverlay(heatmapOverlay);
}

Response.Buffer = true;
Response.Expires = -1;
Response.ContentType = "image/png";

double lat1 = Convert.ToDouble(Request["lat1"]);
double lat2 = Convert.ToDouble(Request["lat2"]);
double lon1 = Convert.ToDouble(Request["lon1"]);
double lon2 = Convert.ToDouble(Request["lon2"]);

GenericDataAccess d = new GenericDataAccess(System.Configuration.ConfigurationManager.ConnectionStrings["mydatabase"].ToString());
string sql = "SELECT [" + "Latitude" + "], [" + "Longitude" + "], [" + "Traffic1" + "] FROM [" + "Kansas_Traffic" + "]";
sql += " WHERE Latitude Between " + lat2 + " AND " + lat1;
sql += " AND Longitude Between " + lon1 + " AND " + lon2;

GEOHeatMap.Heatmap hm = new GEOHeatMap.Heatmap(Convert.ToInt16(Request["w"]), Convert.ToInt16(Request["h"]), lat1, lat2, lon1, lon2);
DataSet ds = d.GetData(sql); // Call to your DB here

hm.SetDataFromDataSet(ref ds);
ds.Dispose();

Bitmap bmp = hm.Render();
System.IO.MemoryStream imageStream = new System.IO.MemoryStream();
bmp.Save(imageStream, System.Drawing.Imaging.ImageFormat.Png);
long len = imageStream.Length;
Byte[] imageBytes = new Byte[len + 1];
imageStream.Position = 0;
int totalRead = imageStream.Read(imageBytes, 0, (int)len);

Response.BinaryWrite(imageBytes);

imageStream.Close();
bmp.Dispose();