Rob Atkinson a écrit :
> My thought, and it was confirmed in some discussions with Bryce and also 
> some private conversations with people involved in the DEWS project that 
> was looking at NetCDF, is that metadata is what you get when you take a 
> Feature view of a coverage.

Probably, it make sense.


> We should IMHO avoid creating new interfaces when the issue is simply 
> that we have previously crippled Feature to implement the  SimpleFeature 
> profile.

I agree to avoid creating new interfaces when existing ones can fit, and 
actually this "geographic metadata for raster" topic is not about new 
interface. 
It is about providing an implementation of this standard Java Image I/O 
interface:

http://java.sun.com/javase/6/docs/api/javax/imageio/metadata/IIOMetadataFormat.html

A single "standard" implementation could be provided for the whole Geotools 
library and act as a bridge between the standard Java Image I/O framework and 
the Geotools Feature, Coverage or whatever interface we use on our side. The 
choice of a standard IIOMetadataFormat implementation is significant because it 
determine how every javax.imageio.ImageReader implementations shall expose 
their 
metadata to Feature or Coverage builders. It is significant for ImageReader and 
for Feature/Coverage _builders_ (it is really a link between them); it doesn't 
impact Feature or Coverage interfaces themself.

It is a more appropriate to see this topic as "choosing a XML schema" than 
introducing Java API, since IIOMetadataFormat job (in standard Java Image I/O 
mechanism) it to describe a XML schema for metadata exchange between 
ImageReader 
and Factory/Coverage builders. The "GML in JPEG 2000" specification way be the 
XML schema we are looking for.


> I've been wondering about how the ISO19115 object libaries you have been 
> creating behave.

Users can use them (if they wish), as well as some ISO 19111 constructs. 
javax.imageio.metadata.IIOMetadataFormat is a way to said "put the geographic 
envelope there" where "there" is somewhere in javax.imageio.metadata constructs 
(which is why we need to define where we put the envelope, since Image I/O is 
not aware about geographic informations). It doesn't define a new interface for 
this geographic envelope.

I will try to tomorrow a figure showing the proposed IIOMetadataFormat 
definition as a tree.

        Martin


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