Should this include a Google Earth versus Microsofts Virtual Earth? In some ways the argument could be made that GE and World Wind should not be compared at least in a strict fashion, the same is not so true with Virtual Earth and Google Earth. In fact with the recent plugin Google has made which allows Google Earth views embedded within a web page Google has just closed a serious feature gap...
3D viewers for in the web page are now approaching universal in the compared products and is more than a little cool.
What is the over all goal of VE? it seems they are indeed competing with both Google Maps and Google Earth which leaves World Wind still in its own category.
However as a tool for showing Web Map Service Layers Virtual earth it is still quite lacking in someways yet not much more so than Google Earth... For instance the currently suggested technique for doing wms or other custom layers as presented basically requires a server side mimicing the tile service of microsoft itself... not overly difficult but often web page developers do not have this kind of access and it just isnt as versatile as the google maps version of exposing the tile fetching method to outside scripting as used by the Google Maps api. This is not much different than Google Earths KML reflector technique though it does have the tiling advantage...
One Virtual Earth feature in the arena of WMS support that almost works ... is they allow setting the URL for tiles and use String Replacement to put the current tile location values into place... Why This Almost Works ... well because they use a %number as there replacement code... they disallow valid urls .... by using $number this would have been perfect and allowed any valid url as it stands many WMS urls which require url encoding already have and need the % character in them.
The above may not seem like it means much but it is the difference between you being able to easily put up a web page with WMS overlays on VE built in and having to do extra cgi or php or some other server side scripting.
Note Google Earths wms image request on pause technique is not really better due to impoverished user experience. and implementation errors even if it can be dynamically generated.
Wierdly Google Maps, Virtual Earths 2D elements. are highly comparable. Google Maps does have an advantage in that it allows one access to pngs with transparency allowing nice overlay usage. Virtual Earth seems to have a more open licensing scheme. and there layers are even integrated into Dapple and World Wind.
GoogleEarth Pro is now a free and able to import a huge number of formats of data directly now this puts the entire picture at a different slant.
Release of version 1.4 includes a dialog available from the menu for
easier adding of WMS layers and seems to include support of WMS 1.3,
NOTE this code seems prone to errors (not as robust as the WMS controls in Dapple or the Addons creation via TNTmap)
ERROR include problems handling layers from servers which are proven OGC compliant and which work with both Dapple and via TNTmap.
It has been a while since this was first posted and some significant updates have occurred both positive and negative...