[OSGeo-Standards] Was: "file" formats. Is: GeoWeb

Raj Singh rsingh at opengeospatial.org
Thu Jul 11 11:28:34 PDT 2013

On Jul 11, at 2:15 PM, "Rushforth, Peter" <Peter.Rushforth at NRCan-RNCan.gc.ca> wrote:

>> I think the 
>> biggest problem I have with designing RESTful resources 
>> around coverage data is the fact that most coverages 
>> represent natural phenomena that vary continuously across the 
>> earth's surface (or atmosphere, or sub-surface). This means 
>> that the actual cell values are only approximations of what 
>> is expected to be observed in nature. 
> Can a coverage be tiled?  Can you reproduce a coverage data structure by
> re-assembling tiles?

This is exactly the problem. I think coverage loses meaning when it's tiled. It's like graphing a wavelength equation, then snipping out a part of the graph, then trying to recreate the original equation with only that part of the graph. There will probably be many equations that fit the graph. I suppose you could avoid this problem with coverages by maintaining, e.g., something like a "link=source" to the original coverage in the tile data. But I also don't have the professional background in the sciences that use coverages to know if this would be useful.

>> This is why I have a 
>> hard time calling anything a resource other than the full coverage. 
> But, a FeatureCollection is also a Feature, right?  A collection
> can have in principle an unlimited number of features.   A representation
> is just that: a representation of the resource.  Not the whole thing, necessarily.
> Not the beginning of it, nor the end of it necessarily.  If one
> can figure out how to provide access to a part of a resource,
> and potentially link to other parts of it e.g. link at rel="next".

No problem with anything you say here. Actually I emphatically agree the only problem is figuring out those pesky link relations!

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