Using TileCache to connect VirtualEarth and ArcIMS
For the upcoming EagleOne disaster exercise we want to overlay WMS layers on top of Virtual Earth. Already we know how to overlay WMS images on top of VE using TileCache. However this approach uses the 900913 projection. Sometimes you have a WMS server which does not support 900913 and you’re not able to change that.
So here enters the cascading mapserver: UMN Mapserver, and possibly others as well, can function as a cascading mapserver. This means that it acts both as a WMS server, to you, and a WMS client, to another WMS server. This way you can use it to reproject images.
By using both TileCache’s new VMTMS service to serve QuadKey-Tiles and UMN Mapserver reprojecting cascading capabilities I was able to access an ArcIMS server which served epsg:28992 WMS through a WMSconnector and show this data tiled and cached in Virtual Earth. I drew a schema of this:
As you can see two open source components are used to connect two incompatible closed source components; it’s the duct tape of the GIS world 
TileCache on 64bit windows
At work we have a nice new server, which contains a smaller version of Microsoft’s Virtual Earth platform. This machine is still a hefty beast: dual quadcore with 16GB memory and about 8TB of harddisc space. Since there’s still a few TB free we decided that it would be a nice machine to serve up VE-compatible tiles using TileCache, hence my work on VE compatible TileCache classes.
This proved to be much harder then I expected. The problem is that it runs Windows Server 2003 x64, a 64bit OS. Obviously since it is a MS product it already has IIS installed and TileCache doesn’t perform well on IIS. (A side note, I just found this article by Vish and it seems that it might perform after all). So I decided to install Apache alongside it and the necessary Python and mod_python as well. Being a 64bit OS I wanted to install 64bit software.
Apache isn’t available as 64bit binary, neither is mod_python. Only python had a 64bit binary for download. So I installed apache 2.2, python 2.5 (64bit) and checked if they both worked and they did. Mod_python proved to be more difficult so I googled for 64bit mod_python and discovered this article which explained how to compile a 64bit python. There were some problems with it not finding python.exe and some DLLs but that could be solved by adding c:\pyton25 to the PATH environment variable and putting the DLLs in the same directory.
So now I had a 32bit Apache 2.2 (working) a 64bit Python (working) and a 64bit mod_python ready to work. However when I configured Apache to use mod_python it failed with a weird error that %1 was not a valid application. Some more googling revealed that python on a 64bit windows does weird things, or 64bit windows does weird things with python 
Since 32bit Apache already worked I decided to go for 32bit Python as well which together with 32bit mod_python works flawlessly. So if you want to run TileCache on 64Bit windows: just go for the 32bit versions of the software and hope you’re not stuck with an Itanium.
‘Proof’ of TileCache running on 64bit Windows, the 6.82GB RAM usage is baffling since the machine isn’t doing anything