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I have the following field called 51A: enter image description here

I have the following excerpt from the GML file where it describes the 51A field:

<gml:featureMember>
    <ogr:av_export_temp.ihkulroo fid="av_export_temp.ihkulroo.183">
      <ogr:geometryProperty><gml:Polygon><gml:outerBoundaryIs><gml:LinearRing><gml:coordinates>-63613.5803279425,6594849.11111532 -63338.4982627596,6596691.79998076 -61065.5082310117,6596353.15340253 -58792.3850046138,6596015.89007513 -56519.1291541683,6595680.00990826 -54245.7412499302,6595345.51281189 -51972.2218618083,6595012.39869636 -52241.6978222727,6593169.17366796 -54516.3382854795,6593502.39409221 -56790.8473374676,6593836.99795894 -59065.2244085927,6594172.98535813 -61339.468928864,6594510.35638005 -63613.5803279425,6594849.11111532</gml:coordinates></gml:LinearRing></gml:outerBoundaryIs></gml:Polygon></ogr:geometryProperty>
      <ogr:Copyright>Fishdirectory</ogr:Copyright>
      <ogr:Zone>51A</ogr:Zone>
      <ogr:County>Rogaland</ogr:County>
      <ogr:Timereport1>2018/09/11</ogr: Timereport1 >
      <ogr:Timereport2>2019/08/31</ogr:Timereport2>
    </ogr:av_export_temp.ihkulroo>
  </gml:featureMember>
  <gml:featureMember>

The coordinate system used in the GML file is EPSG:25832 ETRS89 / UTM zone 32N

How come the field 51A, that is a basic rectangle, has so many polygon points to describe it? Should not there be just 4 corners?

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    Welcome to GIS SE. As a new user, please take the Tour, which emphasizes the importance of asking One question per Question. Please choose which of these is your most pressing issue, and Edit the question to increase details about that aspect. – Vince Apr 25 '20 at 13:46
  • 2
    4 corners (the make five points because the first and the last must be equal for closing the polygon) would be enough but a few more vertices do not really matter. They may be useful when data are re-projected because the offer additional anchor points. It is also possible thet neighboring polygons are matching these vertices when they are useful for helping to maintain the topology of the whole layer. User can get rid of the extra points easily by simplifying the geometry. – user30184 Apr 25 '20 at 16:11

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