[postgis-devel] ST_MapAlgebra (was: ST_Value performance)

[Pierre Racine]

> Now I tried it and realized that "rast" in the expression refers to the pixel value
> while I don't care about that.
> Instead, I need the _position_ of the pixel.
> That is, my expression is a function of the pixel position, not of its value.
> 
> Would it make sense to then provide that information as well as a placeholder,
> in addition to the value ?

Yes that would be very useful. Could be 'rastx' and 'rasty'.

You would prefer 'pixval', 'pixx' and 'pixy'?

Pierre