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Simple GML Geometry

This note will deal with the simple geometry profile of GML discussed in the previous note. The intention of this profile is to provide a simple introduction to GML and to provide users such as geotaggers, geobloggers and others that have existing grammars but want to embed geometric descriptions. This profile does not include GML feature and hence you cannot construct (at least not in GML) objects of interest such as rivers, lakes, roadways, flight paths etc. We will deal with whole issue of application schemas and feature types in an upcoming BLOG.

One use of this profile might be to annotate a web page with location information related to the page – such as the area "covered" by the web page, or to describe the extent of specific events or occurences within the web page – although in our view this is best done by making use of GML features and some type of Web Feature Service.

So in pseudo-ATOM or pseudo-RSS we might have something like:

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    <news>
      <item>
        <newsitem>
          <description>Katrina destroys refineries in the gulf</description>
          <coverage>
            <gml:polygon></gml:polygon>
          </coverage>
        </newsitem>
      </item>
    </news>

Here the gml:Polygon describes the area covered by the news story. Note that the XML around the gml stuf is NOT a GML Applicaton Schema as it is defined by a grammar external to GML be that RSS, Atom or whatever.

The schema is the READ MORE section. Comments on the schema will appear in an upcoming BLOG.

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