Thursday, June 12, 2008
Posted on Thursday, June 12, 2008 9:53:19 PM (Mountain Daylight Time, UTC-06:00)  Comments [1] | 
Categories: Dojo | Virtual Earth

We just put up another "demo" site - this time working with Sanborn to provide visualization for their wildfire risk model outputs they have created for the Texas Forest Service. For information on the data, there is contact information on the "About" tab.

txfire

From a technical stand-point, we added a few new features to this viewer...

Dealing with Multiple Tile Layers

The viewer is pulling in multiple tile services, representing multiple layers in a map, as opposed to a single "fused" tile layer. This is the first time I've implemented multiple layers using the ArcGIS Server Tile Cache code, and it turns out it's currently a bit of a pain. For this site, we've got 7 tile layers, and to do that with the current tile server code, I needed to create 7 map services (mxd's), and then configure 7 tile services in the TileServer. Clearly this should be streamlined. For example, the url http://204.133.225.164/tileservice/txfirewfsi/023131001.ashx pulls a specific tile from the txfirewfsi tile service. (shown below)

Tile

However, I'm thinking that it would be nice to be able to add a layer name in the url -'parcels' in this case -   http://204.133.225.164/tileservice/txbasemap/parcels/023133.ashx. This way you could specify the fused tiles, or just a specific layer.

Adjusting Layer Transparency

This was easy, if not obvious. Adding in a Dojo.slider, and hooking up some events was pretty simple. However, it turns out that changing the .Opacity property of a VETileSourceSpecification has no effect after the layer has been added to map. Instead you need to delete the layer and re-add it with the new opacity. Since the browser is caching the tiles, this is actually very fast.

trans

Virtual Earth 3D

This was also the first time I tried throwing things into 3D mode. It took a few quick tweaks in the javascript, and some different CSS for the markers, but for the most part - it "just worked".

tx-3d

There are a few issues with the dojo menus that I'm going to sort out so I'll save the Url for the 3d page until that's dialed.

So, this took about 3 days to pull together -- if you are looking under the covers, the code is VERY "demo" and has some issues - there are a few weird things with the layer list checkboxes and I have not really tested in IE7, and all bets are off with IE6. I'd love to hear thoughts & ideas though.

Wednesday, July 02, 2008 6:43:05 AM (Mountain Daylight Time, UTC-06:00)
Dave,
Did you come up with a solution regarding streamlining the ArcGIS services configuration? My thought is to have all the tilelayers point to one service. Each VETilelayer includes a parameter of the layer to be rendered. On the server side, your tile handler then creates and retrieves tiles based by calling the AGS service and turning off all layers but the one in the layer parameter before rendering the image. For my project using MapServer, the class that generates the image has a "BeforeMapRender" delegate member that can be used to turn on and off specific layers based on the url parameters just before the map image is rendered.
Max Phelps
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