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Re: Chris Little's comments on the BP - Issues 128 and 204

From: Raphaël Troncy <raphael.troncy@eurecom.fr>
Date: Thu, 18 Feb 2016 19:22:23 +0100
To: Ed Parsons <eparsons@google.com>, George Percivall <gpercivall@opengeospatial.org>
Cc: Jon Blower <j.d.blower@reading.ac.uk>, Frans Knibbe <frans.knibbe@geodan.nl>, SDW WG <public-sdw-wg@w3.org>, Chris Little <chris.little@metoffice.gov.uk>, Jeremy Tandy <jeremy.tandy@gmail.com>
Message-ID: <56C60BDF.20203@eurecom.fr>
Dear Ed, all,

> I do accept there are exceptions... what is your estimate of the % of
> spatial data on the web that is not CRS84 ?

This is a tricky question to answer in general, but I second the opinion 
that states that there is a LOT of spatial data on the web which is not 
CRS84, and in particular, authoritative data.

Let's take an example, the official French Open Data Portal 
https://www.data.gouv.fr/fr/datasets/ ... there are thousands of 
datasets, coming from both the public administration and the private 
sectors. Most of the data is geo-localized ... and rarely the CRS used 
is WGS84. For example, pick the dataset that describes ALL 
(primary/secondary) schools in France [1] and try to plot the schools on 
a map by interpreting that the coordinates are in WGS84 ... you will 
find many schools in the ocean. In this dataset, you have to interpret 
the geo coordinates of the schools in France Metropolitan in RGF93, the 
ones in Guadeloupe/Martinique in CRS84, the ones in Guyanne in RGFG95, 
the ones in Réunion in RGR92, etc.

This is not an exception ... this is the rule! All official data from 
the French public administration will come in RGF93 (Lambert93). Many 
European countries have similar rules.

This does definitively not cover 1% of the spatial data on the web



Raphaël Troncy
EURECOM, Campus SophiaTech
Data Science Department
450 route des Chappes, 06410 Biot, France.
e-mail: raphael.troncy@eurecom.fr & raphael.troncy@gmail.com
Tel: +33 (0)4 - 9300 8242
Fax: +33 (0)4 - 9000 8200
Web: http://www.eurecom.fr/~troncy/
Received on Thursday, 18 February 2016 18:22:55 UTC

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