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To have a cleaner map to print I want to display only the boundary of a layer composed of more than 200,000 features (all adjacent).

Is there something more straightforward than dissolving or merging all the polygons?

I'm using QGIS.

PolyGeo
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FabianUx
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  • may be outdated but possible duplicate: http://gis.stackexchange.com/questions/68735/calculating-mcp-in-qgis – mkennedy Jun 17 '15 at 20:48
  • If you don't want to actually merge your polygons see http://gis.stackexchange.com/questions/8571/how-to-hide-internal-polygon-boundaries – John Jun 18 '15 at 11:55

1 Answers1

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In QGIS use the dissolve function from menu: Vector > Geoprocessing Tools > Dissolve... This will get you a new table with only the outer perimeter geometry.

Jakob
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  • Thanks. I was avoiding this option because it takes 1 day processing, lots of polygons with a 100 attributes. For the dissolve field I had to take an attribute with the same value for all features. – FabianUx Jun 22 '15 at 23:08
  • Well, it takes a few minutes in ArcGIS without attribute selection (the resulting shapefile losses some properties but it is ok for visualization purposes). QGIS with dissolve_all algorithm is not working so far. – FabianUx Jul 02 '15 at 18:40