[georss] gml:DirectPositionListType

[Farrukh Najmi]

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