Display Multiple Layers Using PortlandTiledMapServiceLayer Example

[GlennKirbo]

I am trying to get a Custom Tiled Map Service layer to display with a base map layer below it.
The PortlandTiledMapServiceLayer Example works fine until I try to add a base layer of imagery by changing 1 line of mxml. (code below).  When I run the app I get no errors but only one layer appears.  If I list the base layer first I just get it and if I list the portland layer first I just get it. What am I missing?

<esri:Map id="myMap">
  <esri:ArcGISTiledMapServiceLayer url="http://services.arcgisonline.com/ArcGIS/rest/services/World_Imagery/MapServer" />
  <samples:PortlandTiledMapServiceLayer id="virtualTiles" fadeInFrameCount="12"  alpha=".5" opaqueBackground="false" />
 </esri:Map>

[RobertScheitlin__GISP]

Glenn,

   The issue is that both tiled (Cached) map services need to have the same LODs (Levels of Display) with in your case they do not. I don't have the specifics for you of what needs to be changed but this function in the PortlandTiledMapServiceLayer need to be updated ti have the same LODs as ArcGIS Online.

private function buildTileInfo():void
    {
        _tileInfo.height = 512;
        _tileInfo.width = 512;
        _tileInfo.origin = new MapPoint(-180, 90);
        _tileInfo.spatialReference = new SpatialReference(4326);
        _tileInfo.lods = [
            new LOD(0, 0.351562499999999, 147748799.285417),
            new LOD(1, 0.17578125, 73874399.6427087),
            new LOD(2, 0.0878906250000001, 36937199.8213544),
            new LOD(3, 0.0439453125, 18468599.9106772),
            new LOD(4, 0.02197265625, 9234299.95533859),
            new LOD(5, 0.010986328125, 4617149.97766929),
            new LOD(6, 0.0054931640625, 2308574.98883465),
            new LOD(7, 0.00274658203124999, 1154287.49441732),
            new LOD(8, 0.001373291015625, 577143.747208662),
            new LOD(9, 0.0006866455078125, 288571.873604331),
            new LOD(10, 0.000343322753906249, 144285.936802165),
            new LOD(11, 0.000171661376953125, 72142.9684010827),
            new LOD(12, 0.0000858306884765626, 36071.4842005414),
            new LOD(13, 0.0000429153442382813, 18035.7421002707),
            new LOD(14, 0.0000214576721191406, 9017.87105013534),
            new LOD(15, 0.0000107288360595703, 4508.93552506767)
        ];
    }

[GlennKirbo]

Robert,

Thank you for replying.
I think you are right about the LOD.  The Portland example didn't match the base layer's LOD so I switched from that example to my actual dataset which does match and manually made sure the LOD was the same.  I have a custom external tile set (not arc gis) projected in the standard Mercator(102100) format used by google maps & bing.  The url structure is a little different but otherwise the request pattern should be very similar to the "image tile layer" in the google maps javascript api v3.  I would like to be able to add that layer on top of ERSI layers using the ERSI flex api v2.  I searched through the ArcGIS flex api v2 reference for something like a "Web Mercator Tile Layer Class" that would have all these defaults set for me.. that's what google does with its image tile layer and what I expected to find here but didn't.

My understanding is that ERSI has started supplying tiles in the google / bing projection in a format it calls "Web Mercator".    I also found this page that details the LOD for Web Mercator
http://resources.esri.com/help/9.3/arcgisonline/about/Content/attributes_wm.htm

I set up a simple acr gis base layer and set a break point so I could inspect the code and confirm that these were the LOD being used by the ArcGIS base layer.  It uses 102100 be default which is web mercator.  So then sub classed TiledMapServiceLayer and exactly hand replicated (I think) all the tileInfo, extents and LOD info values to exactly match what the ArcGIS layer showed in the debugger which also matched the list on the link above.  Again, I ran into the same problem. My custom layer works by itself but not on top of an ArcGIS base layer.  This really should be simple to do so I'm probably missing something.  Can any one identify what I'm doing wrong?   (code below)

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
      xmlns:esri="http://www.esri.com/2008/ags"
      xmlns:s="library://ns.adobe.com/flex/spark"
      xmlns:ml="com.MapLarge.*"
      applicationComplete="testLoad()"
      > 
 
 <esri:Map id="gisMap" >
  <esri:ArcGISTiledMapServiceLayer 
   id="baseMap"
   url="http://services.arcgisonline.com/ArcGIS/rest/services/World_Imagery/MapServer"
  />
 
  <ml:MapLargeTileLayer id="virtualTiles" opaqueBackground="false"   />
 </esri:Map>
 
 <fx:Script>
  <![CDATA[
   private function testLoad():void{
    var mapObj:Object = gisMap; 
    var layerObj:Object = baseMap; //inspect with debugger
   }
  ]]>
 </fx:Script>
 
</s:Application>

MapLargeTileLayer.as

package com.MapLarge
{
 import com.esri.ags.SpatialReference;
 import com.esri.ags.geometry.Extent;
 import com.esri.ags.geometry.MapPoint;
 import com.esri.ags.layers.TiledMapServiceLayer;
 import com.esri.ags.layers.supportClasses.LOD;
 import com.esri.ags.layers.supportClasses.TileInfo;
 import flash.net.URLRequest;
 import mx.containers.Tile;
 
 public class MapLargeTileLayer extends TiledMapServiceLayer
 {
  public function MapLargeTileLayer()
  {
   super();
   buildTileInfo();
   setLoaded(true); // Map will only use loaded layers
  }
  
  internal const scalar:Number = 1;
  public var _tileInfo:TileInfo;
  private function buildTileInfo():void
  {
   var tileInfo:TileInfo = new TileInfo();
   tileInfo.spatialReference = new SpatialReference(102100);
   tileInfo.dpi = 96;
   tileInfo.format = "PNG8";
   tileInfo.width = 256;
   tileInfo.height = 256;
   tileInfo.origin = new MapPoint(-2.0037508342787E7,2.0037508342787E7);
   
   tileInfo.lods = [
    new LOD(0,156543.033928,591657528),
    new LOD(1,78271.516964,295828764),
    new LOD(2,39135.758482,147914382),
    new LOD(3,19567.879241,73957191),
    new LOD(4,9783.93962,36978595),
    new LOD(5,4891.96981,18489298),
    new LOD(6,2445.984905,9244649),
    new LOD(7,1222.992453,4622324),
    new LOD(8,611.496226,2311162),
    new LOD(9,305.748113,1155581),
    new LOD(10,152.874057,577791),
    new LOD(11,76.437028,288895),
    new LOD(12,38.218514,144448),
    new LOD(13,19.109257,72224),
    new LOD(14,9.554629,36112),
    new LOD(15,4.777314,18056),
    new LOD(16,2.388657,9028),
    new LOD(17,1.194329,4514),
    new LOD(18,0.597164,2257),
    new LOD(19,0.298582,1128)
   ];

   
   _tileInfo = tileInfo;
  }
  
  override public function get fullExtent():Extent
  {
   return new Extent(-2.0037508342787E7, -1.99718688804086E7, 2.0037508342787E7, 1.99718688804086E7,new SpatialReference(102100));
  }
  
  override public function get initialExtent():Extent
  {
   return this.fullExtent;
  }
  
  override public function get units():String
  {
   return "esriMeters";
  }
  
  override public function get spatialReference():SpatialReference 
  {
   return new SpatialReference(102100);//102113
  }
  override public function get tileInfo():TileInfo {
   return _tileInfo;
  }
  
  override protected function getTileURL(level:Number, row:Number, col:Number):URLRequest
  {
   //http://2api.maplarge.com/Tile/Tile?layer=geo~poly~Counties|data~AllGeocodedFinal~DonationCode~sum&x=2&y=5&z=4&filter=&shader=method~interval|count~100|colors~DarkBlue-200/Blue-128,Blue-128/White-128,White-128/Red-128,Red-128/DarkRed-200|ranges~-1000000/-20000,-20000/0,0/20000,20000/1000000
   var one:String = "http://2api.maplarge.com/Tile/Tile?layer=geo~poly~Counties|data~AllGeocodedFinal~DonationCode~sum";
   var two:String = "&x="+col+"&y="+row+"&z="+ level;
   var three:String = "&filter=&shader=method~interval|count~100|colors~DarkBlue-200/Blue-128,Blue-128/White-128,White-128/Red-128,Red-128/DarkRed-200|ranges~-1000000/-20000,-20000/0,0/20000,20000/1000000";
   var url:String = one + two + three;
   return new URLRequest(url);
  }
  
 }
}

[GlennKirbo]

I think I have come up with a test that eliminates LOD as the culprit.
I subclassed the open street map layer and overrode the getTileURL function and that works like a charm.   So "Mercator Web" image tile layer class found.  I then created an app with 2 layers.
Open street map on the bottom and my custom tiles on top... I can briefly see the open street map tiles flash before my custom layer loads on top and then my top layer obscures them.  In firebug I can still see image tile requests for both layers occurring as I pan around so I know think the layers are working and since the classes are identical except for the get tile url function the LOD and tile info issue should be eliminated.  I'm sure it is something simple.  Can anyone help me?
(complete code below for the 2 layer app)

App Code

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
      xmlns:esri="http://www.esri.com/2008/ags"
      xmlns:s="library://ns.adobe.com/flex/spark"
      xmlns:ml="com.MapLarge.*"
      > 

 <esri:Map >
  <esri:OpenStreetMapLayer id="openMap" visible="true" />
  <ml:MapLargeTileLayer2 opaqueBackground="false" alpha=".5" id="myMap" visible="true"   />
 </esri:Map>
 
</s:Application>

Open Street Map Sub Class

package com.MapLarge
{
 import com.esri.ags.layers.OpenStreetMapLayer;
 
 import flash.net.URLRequest;

 public class MapLargeTileLayer2 extends OpenStreetMapLayer
 {
  public function MapLargeTileLayer2()
  {
  }
  
  override protected function getTileURL(level:Number, row:Number, col:Number):URLRequest
  {
   //http://2api.maplarge.com/Tile/Tile?layer=geo~poly~Counties|data~AllGeocodedFinal~DonationCode~sum&x=2&y=5&z=4&filter=&shader=method~interval|count~100|colors~DarkBlue-200/Blue-128,Blue-128/White-128,White-128/Red-128,Red-128/DarkRed-200|ranges~-1000000/-20000,-20000/0,0/20000,20000/1000000
   var one:String = "http://2api.maplarge.com/Tile/Tile?layer=geo~poly~Counties|data~AllGeocodedFinal~DonationCode~sum";
   var two:String = "&x="+col+"&y="+row+"&z="+ level;
   var three:String = "&filter=&shader=method~interval|count~100|colors~DarkBlue-200/Blue-128,Blue-128/White-128,White-128/Red-128,Red-128/DarkRed-200|ranges~-1000000/-20000,-20000/0,0/20000,20000/1000000";
   var url:String = one + two + three;
   return new URLRequest(url);
  }
  
 }
}

[RobertScheitlin__GISP]

Glen,

   You still have a problem with LODs. The debugger is rounding the values of the ArcGIS Online LODs so because they are not identical both layers will not display together. To get the exact values of the LODs in one of ESRI you need to look at it's REST service directory page.

Here is the corrected code.

package com.MapLarge
{
 import com.esri.ags.SpatialReference;
 import com.esri.ags.geometry.Extent;
 import com.esri.ags.geometry.MapPoint;
 import com.esri.ags.layers.TiledMapServiceLayer;
 import com.esri.ags.layers.supportClasses.LOD;
 import com.esri.ags.layers.supportClasses.TileInfo;
 import flash.net.URLRequest;
 import mx.containers.Tile;
 
 public class MapLargeTileLayer extends TiledMapServiceLayer
 {
  public function MapLargeTileLayer()
  {
   super();
   buildTileInfo();
   setLoaded(true); // Map will only use loaded layers
  }
  
  internal const scalar:Number = 1;
  public var _tileInfo:TileInfo;
  private function buildTileInfo():void
  {

   var tileInfo:TileInfo = new TileInfo();
   tileInfo.spatialReference = new SpatialReference(102100);
   tileInfo.dpi = 96;
   tileInfo.format = "PNG8";
   tileInfo.width = 256;
   tileInfo.height = 256;
   tileInfo.origin = new MapPoint(-2.0037508342787E7,2.0037508342787E7);
   
   tileInfo.lods = [
    new LOD(0,156543.033928,591657527.591555),
    new LOD(1,78271.5169639999,295828763.795777),
    new LOD(2,39135.7584820001,147914381.897889),
    new LOD(3,19567.8792409999,73957190.948944),
    new LOD(4,9783.93962049996,36978595.474472),
    new LOD(5,4891.96981024998,18489297.737236),
    new LOD(6,2445.98490512499,9244648.868618),
    new LOD(7,1222.99245256249,4622324.434309),
    new LOD(8,611.49622628138,2311162.217155),
    new LOD(9,305.748113140558,1155581.108577),
    new LOD(10,152.874056570411,577790.554289),
    new LOD(11,76.4370282850732,288895.277144),
    new LOD(12,38.2185141425366,144447.638572),
    new LOD(13,19.1092570712683,72223.819286),
    new LOD(14,9.55462853563415,36111.909643),
    new LOD(15,4.77731426794937,18055.954822),
    new LOD(16,2.38865713397468,9027.977411),
    new LOD(17,1.19432856685505,4513.988705),
    new LOD(18,0.597164283559817,2256.994353),
    new LOD(19,0.298582141647617,1128.497176)
   ];
   
   
   _tileInfo = tileInfo;
  }
  
  override public function get fullExtent():Extent
  {
   return new Extent(-2.0037508342787E7, -1.99718688804086E7, 2.0037508342787E7, 1.99718688804086E7,new SpatialReference(102100));
  }
  
  override public function get initialExtent():Extent
  {
   return this.fullExtent;
  }
  
  override public function get units():String
  {
   return "esriMeters";
  }
  
  override public function get spatialReference():SpatialReference 
  {
   return new SpatialReference(102100);//102113
  }
  override public function get tileInfo():TileInfo {
   return _tileInfo;
  }
  
  override protected function getTileURL(level:Number, row:Number, col:Number):URLRequest
  {
   //http://2api.maplarge.com/Tile/Tile?layer=geo~poly~Counties|data~AllGeocodedFinal~DonationCode~sum&x=2&y=5&z=4&filter=&shader=method~interval|count~100|colors~DarkBlue-200/Blue-128,Blue-128/White-128,White-128/Red-128,Red-128/DarkRed-200|ranges~-1000000/-20000,-20000/0,0/20000,20000/1000000
   var one:String = "http://2api.maplarge.com/Tile/Tile?layer=geo~poly~Counties|data~AllGeocodedFinal~DonationCode~sum";
   var two:String = "&x="+col+"&y="+row+"&z="+ level;
   var three:String = "&filter=&shader=method~interval|count~100|colors~DarkBlue-200/Blue-128,Blue-128/White-128,White-128/Red-128,Red-128/DarkRed-200|ranges~-1000000/-20000,-20000/0,0/20000,20000/1000000";
   var url:String = one + two + three;
   return new URLRequest(url);
  }
  
 }
}

[GlennKirbo]

Robert,

I really appreciate your help.  You were right that the LOD numbers were rounded. 
However, when I replace them with your un-rounded numbers I get the same result.

The good news is that the Open Street Map base layer using my sub class example above with my tile overlay is now working for me.  The problem with that was these attributes: opaqueBackground="false" alpha=".5"  When I remove them from the overlay example above and now it works properly.  Might be a cross domain policy limit or something else odd because those attributes don't seem like they should break the layer. Full working code included below 🙂

On your LOD implementation, I bet there is probably an error somewhere in your numbers just like mine which is why I was surprised there wasn't a static constant structure to supply these decimals for the default projection.  Also the lack of any error or warning about the bad LOD match is weird. If I get more time I will investigate.  There weren't any examples in the demo galleries that had two image tile layers on top of each other.  Do you know of a working example I could look at if I decide to switch off the Open Street Map sub class?  

Glenn

App Code

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
      xmlns:s="library://ns.adobe.com/flex/spark"
      xmlns:mx="library://ns.adobe.com/flex/mx"
      xmlns:esri="http://www.esri.com/2008/ags"
      xmlns:ml="com.MapLarge.*" >
 <esri:Map >
  <esri:ArcGISTiledMapServiceLayer id="baseMap" url="http://server.arcgisonline.com/ArcGIS/rest/services/World_Terrain_Base/MapServer"
   />
  <ml:MapLargeTileLayer2 visible="true"   />
 </esri:Map>

</s:Application>

MapLargeTileLayer2.as

package com.MapLarge
{
 import com.esri.ags.layers.OpenStreetMapLayer;
 
 import flash.net.URLRequest;

 public class MapLargeTileLayer2 extends OpenStreetMapLayer
 {
  public function MapLargeTileLayer2()
  {
  }
  
  override protected function getTileURL(level:Number, row:Number, col:Number):URLRequest
  {
   //http://2api.maplarge.com/Tile/Tile?layer=geo~poly~Counties|data~AllGeocodedFinal~DonationCode~sum&x=2&y=5&z=4&filter=&shader=method~interval|count~100|colors~DarkBlue-200/Blue-128,Blue-128/White-128,White-128/Red-128,Red-128/DarkRed-200|ranges~-1000000/-20000,-20000/0,0/20000,20000/1000000
   var one:String = "http://2api.maplarge.com/Tile/Tile?layer=geo~poly~Counties|data~AllGeocodedFinal~DonationCode~sum";
   var two:String = "&x="+col+"&y="+row+"&z="+ level;
   var three:String = "&filter=&shader=method~interval|count~100|colors~DarkBlue-200/Blue-128,Blue-128/White-128,White-128/Red-128,Red-128/DarkRed-200|ranges~-1000000/-20000,-20000/0,0/20000,20000/1000000";
   var url:String = one + two + three;
   return new URLRequest(url);
  }
  
 }
}

[RobertScheitlin__GISP]

Glen,

   Using this sample app I can get the code to work fine. As you can see in the attached image. I forgot to mention the opaqueBackground="false" is not correct  Here is the documentation on it.

If set to a number value, the surface is opaque (not transparent) with the RGB background color that the number specifies. If set to null (the default value), the display object has a transparent background.

The opaqueBackground property is intended mainly for use with the cacheAsBitmap property, for rendering optimization. For display objects in which the cacheAsBitmap property is set to true, setting opaqueBackground can improve rendering performance.

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
      xmlns:esri="http://www.esri.com/2008/ags"
      xmlns:s="library://ns.adobe.com/flex/spark"
      xmlns:ml="com.MapLarge.*"
      applicationComplete="testLoad()"
      > 
 
 <esri:Map id="gisMap" >
  <esri:ArcGISTiledMapServiceLayer 
   id="baseMap"
   url="http://services.arcgisonline.com/ArcGIS/rest/services/World_Imagery/MapServer"/>
  <ml:MapLargeTileLayer id="virtualTiles" />
  
 </esri:Map>
 
 <fx:Script>
  <![CDATA[
   private function testLoad():void{
    var mapObj:Object = gisMap; 
    var layerObj:Object = baseMap; //inspect with debugger
   }
  ]]>
 </fx:Script>
</s:Application>

[GlennKirbo]

Robert,

You were right.  Your method works as well.
I must have had a copy and paste error before.
Thank you for your help!

(code below in case anyone needs it)

App

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
      xmlns:s="library://ns.adobe.com/flex/spark"
      xmlns:mx="library://ns.adobe.com/flex/mx"
      xmlns:esri="http://www.esri.com/2008/ags"
      xmlns:ml="com.MapLarge.*" >
 <esri:Map >
  <esri:ArcGISTiledMapServiceLayer url="http://server.arcgisonline.com/ArcGIS/rest/services/World_Terrain_Base/MapServer"
   />
  <ml:MapLargeTileLayer visible="true"   />
 </esri:Map>

</s:Application>

MapLargeTileLayer.as

package com.MapLarge
{
 import com.esri.ags.SpatialReference;
 import com.esri.ags.geometry.Extent;
 import com.esri.ags.geometry.MapPoint;
 import com.esri.ags.layers.TiledMapServiceLayer;
 import com.esri.ags.layers.supportClasses.LOD;
 import com.esri.ags.layers.supportClasses.TileInfo;
 import flash.net.URLRequest;
 import mx.containers.Tile;
 
 public class MapLargeTileLayer extends TiledMapServiceLayer
 {
  public function MapLargeTileLayer()
  {
   super();
   buildTileInfo();
   setLoaded(true); // Map will only use loaded layers
  }
  
  internal const scalar:Number = 1;
  public var _tileInfo:TileInfo;
  private function buildTileInfo():void
  {
   
   var tileInfo:TileInfo = new TileInfo();
   tileInfo.spatialReference = new SpatialReference(102100);
   tileInfo.dpi = 96;
   tileInfo.format = "PNG8";
   tileInfo.width = 256;
   tileInfo.height = 256;
   tileInfo.origin = new MapPoint(-2.0037508342787E7,2.0037508342787E7);
   
   tileInfo.lods = [
    new LOD(0,156543.033928,591657527.591555),
    new LOD(1,78271.5169639999,295828763.795777),
    new LOD(2,39135.7584820001,147914381.897889),
    new LOD(3,19567.8792409999,73957190.948944),
    new LOD(4,9783.93962049996,36978595.474472),
    new LOD(5,4891.96981024998,18489297.737236),
    new LOD(6,2445.98490512499,9244648.868618),
    new LOD(7,1222.99245256249,4622324.434309),
    new LOD(8,611.49622628138,2311162.217155),
    new LOD(9,305.748113140558,1155581.108577),
    new LOD(10,152.874056570411,577790.554289),
    new LOD(11,76.4370282850732,288895.277144),
    new LOD(12,38.2185141425366,144447.638572),
    new LOD(13,19.1092570712683,72223.819286),
    new LOD(14,9.55462853563415,36111.909643),
    new LOD(15,4.77731426794937,18055.954822),
    new LOD(16,2.38865713397468,9027.977411),
    new LOD(17,1.19432856685505,4513.988705),
    new LOD(18,0.597164283559817,2256.994353),
    new LOD(19,0.298582141647617,1128.497176)
   ];
   
   
   _tileInfo = tileInfo;
  }
  
  override public function get fullExtent():Extent
  {
   return new Extent(-2.0037508342787E7, -1.99718688804086E7, 2.0037508342787E7, 1.99718688804086E7,new SpatialReference(102100));
  }
  
  override public function get initialExtent():Extent
  {
   return this.fullExtent;
  }
  
  override public function get units():String
  {
   return "esriMeters";
  }
  
  override public function get spatialReference():SpatialReference 
  {
   return new SpatialReference(102100);//102113
  }
  override public function get tileInfo():TileInfo {
   return _tileInfo;
  }
  
  override protected function getTileURL(level:Number, row:Number, col:Number):URLRequest
  {
   var one:String = "http://2api.maplarge.com/Tile/Tile?layer=geo~poly~Counties|data~AllGeocodedFinal~DonationCode~sum";
   var two:String = "&x="+col+"&y="+row+"&z="+ level;
   var three:String = "&filter=&shader=method~interval|count~100|colors~DarkBlue-200/Blue-128,Blue-128/White-128,White-128/Red-128,Red-128/DarkRed-200|ranges~-1000000/-20000,-20000/0,0/20000,20000/1000000";
   var url:String = one + two + three;
   return new URLRequest(url);
  }
  
 }
}

[RobertScheitlin__GISP]

Glenn,

   I went to maplage.com yesterday and I am a little unclear what the site is all about and where to find info on the API? Can you clear this up for me?

[GlennKirbo]

Robert,

The API at MapLarge.com is a tile rendering engine that takes AcrGIS output like Shape Files or CSV text files and indexes the point and data elements in memory so that tiles and related summaries of feature data in xml, json or amf format can quickly be generated on the fly. It is definitely not an ArcGIS replacement but more of a plugin designed to provide extra performance.   An ArcGIS server can automatically upload a new file to one of our index servers as data changes and the re-indexing processing takes about 10 seconds for a 1GB shape file. The server can also maintain a working copy while the new version is indexed so the flow is seamless.

The  key features are simplicity, on hover feed back for millions of points and polygons and the ability to filter and re-total large data sets on the fly.  The entire process is driven by simple get requests. 

About 30 private client websites are using the system now and we are getting ready to open up the system and formalize the API docs.  I am planning to add ArcGIS Flex Client 2.0 support as part of the API doc roll out this week. 

The example above is a port of this site
http://LobbyData.com/Donors  which is a map of about 3 million political contributors that is generated on the fly without tile caching.

Here is a break down of the request pattern for a tile in the example above
Layer Type & Data
layer=geo~poly~Counties|data~AllGeocodedFinal~DonationCode~sum
The layer geography will be polygons from the US County file and data from the point file AllGeocodedFinal will be projected onto the shapes and values in the field DonationCode will be totaled by county.

Filters
No filter is being applied to the points with DonationCode values in the example above
filter=
Here is an example with a filter for recipients with hillary in their name
filter=RecipientName~ContainsOr~hillary

Shader
shader=method~interval|count~100|colors~DarkBlue-200/Blue-128,Blue-128/White-128,White-128/Red-128,Red-128/DarkRed-200|ranges~-1000000/-20000,-20000/0,0/20000,20000/1000000

There are about a dozen different shader methods that can be applied. Here we are telling the tile server to apply the interval function to create a spectrum of 100 colors and specifying the color and value ranges.   

You can play with the format just by taking this url and switching around values.
http://0api.maplarge.com/Tile/Tile?layer=geo~dot~XY|data~AllGeocodedFinal~DonationCode&x=8&y=13&z=5&...

Here is a more complicated consumer site that makes extensive use of the api
http://hotelmapsearch.com/