Don't get me wrong, I think REW is great.
I've worked with heat maps before, in fact, I've written applications with them.
In many applications they are much easier to see the 3D data without getting lost.
They are not as easy to guage the level because color is used for the level.
But they are great for visualizing.
The application I did would allow the user to zoom in (with a drag rectangle) and it would rescale the colors Z (amplitude) for the data contained in that X-Y region (Time - Freq here).
It also had a double ended slider that would allow the user to clip "Z" from either end (very similar to how the IR window works functionally). Allowing a horizontal slice.
Just the basic heat map would be great though and it's pretty easy, I'm sure the author knows.
You can see in the application below how clear the room mode is in the heat map.
http://www.xtz.se/produkt.php?matnin...kt=41&eng=true