[GRASS-dev] [GRASS GIS] #2550: Polygons disappear after v.generalize simplification

GRASS GIS trac at osgeo.org
Fri Jan 16 13:44:20 PST 2015


#2550: Polygons disappear after v.generalize simplification
------------------------------------------------------------+---------------
 Reporter:  dido                                            |       Owner:  grass-dev@…              
     Type:  defect                                          |      Status:  new                      
 Priority:  major                                           |   Milestone:  6.4.5                    
Component:  Vector                                          |     Version:  6.4.4                    
 Keywords:  Polygons disappear v.generalize simplification  |    Platform:  MSWindows 7              
      Cpu:  x86-64                                          |  
------------------------------------------------------------+---------------

Comment(by mmetz):

 Replying to [ticket:2550 dido]:
 > Polygons disappear after v.generalize simplification.
 >
 > A large rectangular polygon dataset is used with ~14 000 features.
 > Polygons are first processed with rmarea to remove all polygons of size
 900 m2. Then a simplification is executed with v.generalize using a factor
 of 10, all other parameters defaulted.
 >
 > After simplification several large polygons are missing from the set
 rendering it useless.
 >
 > System is a win7x64; QGIS 2.6.1 and GRASS 6.4.4
 >
 > Dataset can be provided upon request (being a 7.5mb shapefile).
 >

 I assume the workflow is v.in.ogr + v.clean tool=rmarea + v.generalize
 threshold=10.

 Several functions relating to v.generalize have just been fixed in trunk
 and I would like to test. Can you please provide a link to the shapefile
 or send the shapefile to markus.metz.giswork at gmail dot com? Thanks!

-- 
Ticket URL: <http://trac.osgeo.org/grass/ticket/2550#comment:1>
GRASS GIS <http://grass.osgeo.org>



More information about the grass-dev mailing list