[Geojson] GeometryCollection not treated as a Geometry type

[John Herring]

Not wanting to pollute your Wiki, I did it quickly in a Word document
(tracking on, with a few selected comments). Emphasis on quick. 

Ignore the format changes, they were to help me keep track. 

The issues are:

	1. ordinate order. EPSG does something different for Lat, Long  and
UTM. It is Lat-long, but it also is East-North. Go figure. May have
something to do with UTM which rotates stuff anyway.  

	2. geometry interpretations, orientations etc. There is an
inconsistency on some details in the orientation issues on polygons (which
could be ignored, but the purpose of Json is program to program, so if it
internally needs to be consistent, it should be consistent in the transfer
format).

	3. feature model has unneeded restrictions.  ISO 19109 (the
authority on the feature model) does not require a feature to have one
geometry, nor require it not to have more than one. It also does not require
a specific name for that geometry property. We have spent the last 30 years
trying to get away from restrictions like that, and yet GeoJson (I do keep
on putting the "a" in that) seems determined to infect a new generation of
programmers with the errors of the past. Personally, I thing we should let
them make their own errors. B^}

	4. some possibly minor confusions. I am still not sure if the
examples cover a wide enough spectrum. We need to be careful that a limited
example set is not interpreted as you can't do unlimited things. Hence a
need to be careful in delimiting the standards testable requirements. 

Regards,
John

You do what you can when you can because you can.

The opinions expressed in this email are 
purely my own and do not necessarily 
represent the opinions of any organization
or otherwise sane person or persons.

John R. Herring
Architect, Spatial Products
Oracle Corporation
One Oracle Drive
Nashua, New Hampshire 03062
ph: 1 603 897 3216
fx: 1 603 897 3334

Annue cœptis - Novus Ordo Seclorum
  


-----Original Message-----
From: Martin Daly [mailto:Martin.Daly at cadcorp.com] 
Sent: Monday, October 08, 2007 10:44 AM
To: John Herring; Andrew Turner
Cc: geojson at lists.geojson.org
Subject: RE: [Geojson] GeometryCollection not treated as a Geometry type

> You guys are spending way too much time being different for no
apparent
> reason. It is a waste of your time, and will be a waste of the time of
the
> reader who will have to realize the differences in rules in each 
> specification instead of following a consistent approach for all OGC 
> specification of geometry representations. Occam and Einstein both saw
that
> simple things should be done simply.

In which case, could you do the wiki thing and create a draft version 7 with
improved wording, so that everyone can understand the implications.

M
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