* A parameter is needed to get a directional bearing, which way, direction is the user looking (in decimal deg?)
* A parameter (may be) is needed to indicate azimuth or declination of the view, up/down (in decimal deg?)
* A parameter is needed to indicate the field of view. Left to right limits. (in decimal deg?)
Some possible optional items:
* A method for horizon alignment, for the vertical orientation. You may want to artificially slide the horizon line up a bit, to better fill the result output.
* Some additional Labeling options for adding in Balloons (this based on your example), figured I use it to add in the idea here. :c)
I would personally like to see this type of skewed image out as a output option for MapServer, because I would also like to use the IMAGE map templating as well out of MapServer. Althoug I can see some of this needing some enhancements as well. Lets say I added in 3D (looking) symbols to the output, it would be nice to scale them smaller as they get further away. The Imagemap aspect would need some sort of corresponding stretch applied to it as well. My use is for ASsset management tasks, where the user could have popups attached to symbols.
My use case, is to apply this type of capability to any oblique photograph, that I also have the camera data for. I already have a datset like this with 4million photo's around the City, and I'm in the middle on contracting out for a newer version. The key is to get the camera data, which I have. So I plan to use the Photo as the projection and apply our other layers to them, using the photo as the background for the map.
May be more than anyone else is wanting though. So I'll be quiet about it now (for a while)