[Live-demo] [OSGeo] #689: NaturalEarth Character Encodings

[OSGeo]

#689: NaturalEarth Character Encodings
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 Reporter:  darkblueb  |       Owner:  darkblueb                        
     Type:  defect     |      Status:  new                              
 Priority:  normal     |   Milestone:  OSGeoLive6.5                     
Component:  LiveDVD    |    Keywords:  4.5beta3, natural earth, upstream
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Comment(by hamish):

 Replying to [comment:8 nvkelso]:
 > The problem is with GRASS, or any other GIS, is when the topology is
 built,
 > it will actually result in odd little sliver polygons and the like.

 that doesn't happen in GRASS actually.. (which is why I recommended it)
 It supports simple features, but its native model is different.
 Or to say, it doesn't happen in GRASS -if the imported data is clean-, and
 it will highlight areas and nodes which are not clean for you, so you can
 clean it up. (e.g. I seem to recall cleaning up an old iteration of the NE
 data for some topology errors around the Great Lakes)

 > It might **seem** like the topology is now clean, and it is
 mathematically,
 > but it's not visually or from a longer term data attribute maintenance
 > perspective.

 the way GRASS's native vector engine does it is that the boundary between
 two abutting areas is a ''single'' line, not two overlapping lines. so you
 can eg reproject that area cleanly, then export the result to back into
 multiple polygon shapefile or whatever without errors due to floating
 point precision issues etc.

 Sorry, I can't speak much about PostGIS and GEOS's vector models, as I'm
 not an expert in those.


 best,
 Hamish

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Ticket URL: <https://trac.osgeo.org/osgeo/ticket/689#comment:9>
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