Using the [`proj=tpers`](http://trac.osgeo.org/proj/wiki/proj%3Dtpers) projection, define a tilted perspective view using:

 * `h`: height (in meters) above the surface
 * `azi`: bearing (in degrees) from due north
 * `tilt`: angle (in degrees) away from nadir
 * `lat_0`: latitude (in degrees) of the view position
 * `lon_0`: longitude (in degrees) of the view position

Putting it all together, here is an example PROJ.4 string for part of Europe:

    +proj=tpers +ellps=WGS84 +h=5000000 +azi=30 +tilt=40 +lat_0=20 +lon_0=0