[Geojson] GeoJSON '1.0'?
Tim Schaub
tschaub at openplans.org
Wed Mar 12 22:20:04 PDT 2008
For clarification:
I'm responding the the current draft (which uses EPSG:4326) and saying
that I don't think coordinate_order is needed.
The simple question is whether this should be a valid representation of
a point in the northern hemisphere:
{
"type": "Point",
"coordinates": [-10, 10],
"crs": {
"type": "EPSG",
"properties": {
"code": 4326,
}
}
}
I think it should.
Christopher Schmidt wrote:
> On Wed, Mar 12, 2008 at 09:27:16PM -0600, Tim Schaub wrote:
>> Hey-
>>
>> Allan Doyle wrote:
>>> Yes, I'm generally +1, but I'm sliding from -0 to -0.1 on
>>> coordinate_order.
>>>
>> After proposing coordinate_order (to satisfy imaginary people who I
>> thought would claim that EPSG literature dictated the meaning of our
>> coordinates array instead of the GeoJSON spec), I also am now sliding
>> toward -1 on the idea.
>>
>> Here's why. If someone tells me that they've got a location that is 10
>> degrees north and -10 degrees east, and they tell me that the CRS is
>> referred to by EPSG:4326, I don't want to have to look anywhere except
>> for the GeoJSON spec to know how to encode that in GeoJSON. (I know the
>> EPSG:4326 example is there.)
>
> Draft5 before this change did not support EPSG:4326: it was explicitly
> disallowed, no? There was no example of how to encode coordinates in
> lon/lat with an included CRS, I don't think. (There was a partial CRS
> definition inside the spec: perhaps this was enough.)
>
>> My point is, if we really are trying to
>> limit the number of dependencies for dumb clients, we shouldn't force
>> everybody to know that EPSG:4326 requires something like
>> "coordinate_order": [1, 0].
>
> In which case we force clients to know that EPSG:4326 is really spelled
> urn:ogc:CRS84 or whatever.
>
>> Apologies for reversing positions, but I now don't want coordinate_order
>> in there at all.
>>
>> So, if others agree, I will happily edit the spec to remove
>> coordinate_order. That is, as long as *nobody* thinks there is a
>> problem saying that this point is in the northern hemisphere (and is
>> perfectly valid GeoJSON):
>>
>> {
>> "type": "Point",
>> "coordinates": [-10, 10],
>> "crs": {
>> "type": "EPSG",
>> "properties": {
>> "code": 4326,
>> }
>> }
>> }
>
> This is not valid GeoJSON under the previous version of the spec: it is
> explicitly disallowed by the CRS section.
>
> The biggest reason to add coordinate_order was to make this allowable
> (with some extra data). If we were fine with this to begin with, then
> the spec was wrong. The spec was written the way it was based on the
> opinion, expressed by several different reasonably competent people,
> that doing what you have done above is not 'allowed'. (Why this is, I
> don't know, but it seems like EPSG easily gets cranky about the use of
> their letters. Don't ask me how realistic this problem is.)
>
> If we really don't care about pissing off EPSG: that's fine, but simply
> ignoring the reason that coordinate_order was useful is not the best way
> to go about handling the situation, in my opinion.
>
> Regards,
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