[Geojson] GeoJSON '1.0'?

Martin Daly Martin.Daly at cadcorp.com
Thu Mar 13 06:55:25 PDT 2008


> How about this:
> 
> Current Draft 5:
>   "If a GeoJSON object has a member named "crs", it is assumed to
> represent the coordinate reference system of the included geometry or
> geometries."
> 
> Proposed fix:
>   "If a GeoJSON object has a member named "crs", it is assumed to
> represent the SOURCE coordinate reference system of the included
> geometry or geometries. In other words, the coordinates in GeoJSON
> elements ALWAYS follow the order x,y[,z] and ALWAYS are expressed as
> floating point numbers REGARDLESS of the order and representation used
> in the source coordinate system. The "crs" member is STRICTLY a hint
> that expresses the mathematical relationship between the coordinate
> values in the GeoJSON geometries and the real world. " [Capitalization
> can go away, that's just to make it stand out in this email]
> 
> Or something like that. In other words, it should be stressed that
> GeoJSON is not saying the geometries are expressed in the normative
> manner prescribed by the CRS but rather they are transformed from that
> CRS. How the transformation is done is up to the user of GeoJSON since
> some people might even use +-DDMMSS style notation since there are
> EPSG codes that require that as well.

I'd be happy with some words to that effect, and have asked some EPSG
types if they would be too.

> By the way, the only trademark at uspto.gov attached to 'epsg' is
> 'ePSG' and refers to " Computer hardware and software, for use with
> medical patient monitoring equipment, for receiving, processing,
> transmitting and displaying data"

I'm not sure that this is a trademark issue.  Isn't it this part of the
usage terms (http://www.epsg.org/CurrentDB.html#use) the bit that
matters:

"No data that has been modified other than as permitted in these terms
and conditions shall be described as or attributed to the EPSG dataset."

Although... GeoJSON could not be described as supplying or modifying the
data, merely referencing it with caveats.

M



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