[georss] gml:DirectPositionListType

[Carl Reed]

Farrukh -

I would suggest the OGC GML WG email list: gml.sig at lists.opengeospatial.org

Cheers

Carl

----- Original Message ----- 
From: "Farrukh Najmi" <farrukh at wellfleetsoftware.com>
To: <georss at lists.eogeo.org>
Sent: Wednesday, May 21, 2008 1:10 PM
Subject: [georss] gml:DirectPositionListType


> Dear colleagues,
> 
> I am not sure if this is off topic. If so please refer me to a more 
> appropriate forum for general GML 3 spec questions.
> 
> My immediate question is regarding DirectPositionListType. It has a list 
> of doubles which need at least
> srsDimension to be interpretted properly (ie. coordinate count is 
> srsDimension / size of list).
> 
> Spec for GML 3.2.1 says in 10.4.1.2 that srsDimension and count are 
> optional:
> 
> "
> The optional attribute count specifies the number of direct positions in 
> the list. If the attribute count is present
> then the attribute srsDimension shall be present, too.
> The number of entries in the list is equal to the product of the 
> dimensionality of the coordinate reference system
> (i.e. it is a derived value of the coordinate reference system 
> definition) and the number of direct positions.
> "
> 
> My questions are:
> 
>    * How can an app process the list of doubles in a
>      DirectPositionListType without knowing the srsDimension? Is there
>      a default of 2 when it is not specified? If so, where is the
>      default mentioned?
>    * Why is a count attribute needed if there is an srsDimension
>      specified. Would the count not simply be calculated as (size of
>      list ) / srsDImension?
>    * How does one interpret a gml:posList like one below when there is
>      no srsDimension or count available?
>      <gml:posList>45.256 -110.45 46.46 -109.48 43.84 -109.86 45.256
>      -110.45</gml:posList>
> 
> TIA for clarifying this.
> 
> -- 
> Regards,
> Farrukh Najmi
> 
> Web: http://www.wellfleetsoftware.com
> 
> 
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