[OpenLayers-Dev] GML format - unsupported geometry type: box

Paul Dziemiela paul at dziemiela.com
Mon Jul 27 16:13:36 EDT 2009


Hi folks,

I've been reading this thread with a bit of interest.  From what I read
gml:Box was deprecated with GML 3 so does this discussion only apply to GML
2 parsers or does this discussion extend over into the gml:envelope that
replaces gml:box?

>From my reading of the specs, the GML 2 Box element was positioned as a
"primitive geometry type" on the same level as a polygon or point.  However
the GML 3 Envelope element is not - it's an attribute of a primitive
geometry.  I don't think you can map your rectangular backyard as a
gml:envelope and pass it around by itself.  But I think you could do that
with gml:box.

So I think you are all debating whether or not a two-point box is a
legitimate geometry or if not is instead only an attribute of a legitimate
geometry.  It looks like the GML folks went down this road and decided on
the latter.

Cheers,
Paul

-----Original Message-----
From: dev-bounces at openlayers.org [mailto:dev-bounces at openlayers.org] On
Behalf Of Francois Van Der Biest
Sent: Monday, July 27, 2009 4:24 AM
To: Eric Lemoine
Cc: dev at openlayers.org
Subject: Re: [OpenLayers-Dev] GML format - unsupported geometry type: box

On Wed, Jul 22, 2009 at 5:33 AM, Eric
Lemoine<eric.lemoine at camptocamp.com> wrote:
> Hi François
>
>  I do not really have answers to your questions - I hope others will -
> but I'd have one comment on what we should do with GML features with a
> bounding box but without a geometry.
>
> I'd be -1 on creating geometries without coordinates and just bounds
> (option 3), because an OpenLayers geometry's bounds represent the
> bounds of the geometry's coordinates. I don't like the idea of
> creating a geometry from the gml:BoundedBy (option 2) either, because
> gml:BoundedBy and feature.geometry represent two different things -
> gml:BoundedBy is the feature's bounding box while feature.geometry is
> the feature's geometry. So, among your options, option 2 is the one
> that makes the most sense to me. And in addition to option 2 I think
> we could make the GML format parse the gml:BoundedBy/gml:Box element
> and place the result either in feature.bounds if there's no geometry
> or in feature.geometry.bounds if there's a one.
>
> What do you think?

I think you wanted to say that you'd be in favor of option (1)
;-)
I also like the idea of placing the bounds in feature.bounds, or
feature.geometry.bounds if feature.geometry exists.
So, I'm going to rework the patch attached to ticket
http://trac.openlayers.org/ticket/2191

Thank's,
F.
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