Ron Lake wrote:
Hi,
There are two different issues combined here.
1. Integer vs floating values.
2. Dimensionality of the coverage
*Integer vs floating values:*
JPEG 2000 offers support for integers only. It is not clear that this
is a serious constraint since any observation must have only finite
precision and hence can be scaled. This may be a pain, but it is
common in all measurement systems.
Is there a standard way to specify scale and offset values?
*Dimensionality of the coverage:*
In general a coverage can be seen as a function *X* = f(*Y*). The
dimension of X can be some N (N=0,1,2, 3, 4 .. ). With the current
GMLinJP2K specification, the dimensionality of Y is 2 – that is at
each point *p* on a 2D surface (e.g. surface of the earth) we can have
vector quantities *X(p)* = (X1, X2, .. Xn) where each Xi will be in a
different JPEG 2000 codestream.
How do you specify what the Xi are? is that in the GML or in the JPEG ?
Can you specify different units for each ?
So for representation of measurement information the restriction of
GMLJP2K is that it does not allow the points *p *to be in a volume –
note that the surface on which *p* lies can be in 3-space however.
This is not really a restriction of JPEG 2000, however, and I think we
can extend the GML description to allow the description of functions
(as above) over multi-dimensional “volumes”.
If JPEG is 2D, doesnt that limit it to domain dimensionality = 2 ? Is
there a way around that?
Thanks for all the info, its very interesting !
