[Proj] Relationship between proj4 and spatialreference.org

Richard Greenwood richard.greenwood at gmail.com
Wed Jan 2 12:33:39 EST 2013

On Wed, Jan 2, 2013 at 8:37 AM, Howard Butler <hobu.inc at gmail.com> wrote:

> On Jan 2, 2013, at 8:41 AM, Jan Hartmann <j.l.h.hartmann at uva.nl> wrote:
> > Hi Howard,
> >
> > This is a problem, as OpenLayers looks by default to
> spatialreference.org when a projection has not been explicitly defined in
> the javascript code. This happens for example with the "displayProjection"
> item in the map controls. You get the wrong coordinates without being told
> that someting isn't right.
> That seems like a rather fragile way of OpenLayers (OpenLayers does
> reprojection now, or is this still proj.js?)  to engineer things,
> especially considering sr.org's sometimes spotty uptime...

I argued that the automatic lookup of coordinate systems parameters should
be a separate optional module as opposed to the default behavior as it is
now. Including your own definitions was always my intention. I've never
liked the idea of an automatic lookup because the user doesn't know what
they are getting, not to mention the additional dependencies and associated
performance hits.

Having said all that, if the default behavior is to do a lookup on
spatialreference.org, it would be nice if spatialreference.org provided
definitions that were optimized for web/javascript use, i.e. did not
require client-side lookup tables for things like named meridians,
ellipsoids, etc.

Best wishes for the new year,

Richard Greenwood
richard.greenwood at gmail.com
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