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

Raj Singh rsingh at opengeospatial.org
Tue Jul 9 22:24:08 PDT 2013

On Jul 9, at 5:38 PM, "Rushforth, Peter" <Peter.Rushforth at NRCan-RNCan.gc.ca> wrote:

> Raj, 
>> the only practical way to access them is through a query API, not hypermedia, and how RESTful is that?
> *You* don't have to specify a query api, just a format with appropriate link relations.  It's the service implementer's job to figure out how to return (a page of) features.  It's the clients job to pull the feed by following typed links (i.e. 'rel=next').  If *you* try to figure out how to satisfy (all) requests, you're doing the server implementer's job.  Why should you care what the URL looks like?

I get your point, but if every service implementer designs their own way to return (a page of) features, and every client codes to that, I have a hard time envisioning, e.g. a highly performant imagery (or feature) service. I certainly see benefit in this kind of architecture if the goal is behind-the-scenes data crawling, data sharing and/or synchronization, but I can't see the killer client app here. Maybe I'm thinking too old-school GIS? I'd love to see a fleshed-out example of this. In fact, I'm trying to implement something like this on openpois.net. Problem is I can't figure out the best way to implement the links for clients to follow.

>> Imagery: hardest (IMHO). What are good resources? 
> Tiles?  Why shouldn't a resource be a tile and the representation be a (GeoTiff, whatever)?  As you say, it's the same problem as features.  You request a *resource* in a *format* (aka media type), the server returns a representation, hopefully in that format.

So tiles would be some grouping of raster cells? I suppose this could be very useful if we standardized on a tiling scheme for the world (something like WMTS but with higher resolution). This is partly why I'm excited about global grid reference schemes [1][2] and hope OGC does some standards work in this area soon. 

[1] http://www.pdana.com/PHDWWW_files/WGRS.pdf
[2] http://www.geocodingconference.com/agenda/pdfs/2011-ggrs-global-grid-reference-system.pdf

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