[Geojson] GeoJSON '1.0'?

Daniel Morissette dmorissette at mapgears.com
Thu Mar 13 06:36:55 PDT 2008


Christopher Schmidt wrote:
> On Thu, Mar 13, 2008 at 07:43:59AM -0400, Panagiotis (Peter) A. Vretanos wrote:
>> So if you use EPSG:4326 and are encoding the coordinates in x,y (or 
>> long,lat) ... well, Raj said it best "You can't do that."!
> 
> *Why?* The answer is obviously not the same for GeoJSON as it is for
> WMS: In WMS, there was no explicit statement that said "Ignore the CRS:
> It's always in x, y." If the reason that there is a problem is because
> the spec is poorly written, then that problem is *solved* with GeoJSON. 
> 
> Assuming that you override the ordering of the CRS in your spec: why
> can't you use EPSG:4326?
> 

I don't know if you're allowed by the EPSG license to refer to EPSG and 
explicitly override the coordinate order... others such as Frank 
Warmerdam seem to know that license fairly well and could comment on 
that (see for instance 
http://www.mail-archive.com/geotools-devel@lists.sourceforge.net/msg03279.html)

But FWIW, here is a little bit of history: I was in the WMS 1.3.0 RWG at 
OGC when the coordinate order issue was discussed for the nth time (I 
also expressed my frustration about this issue over beers several times 
but that's off-topic for this list). Anyway, back to the point, I 
believe (but could be wrong since I was not there at the time) that an 
attempt had been made by the WMS 1.3.0 RWG before I joined to simply 
state that all CRS use x,y ordering as you suggest here, but later on, 
as part of the ISO review process, it was pointed out that OGC could not 
do that. What I remember of it is essentially that the RWG was told by 
ISO that "if you refer to the EPSG database then you cannot pick and use 
only portions of it, you must adhere to all of it, including coordinate 
order. Period."

I don't know if coordinate order will be an issue if you stay away from 
ISO. Personally I still consider that this coordinate order issue ruined 
the simplicity of WMS... if Geojson can avoid it that would be for the best.

Daniel
-- 
Daniel Morissette
http://www.mapgears.com/



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