I have a TIN model where I remove some of the triangles (see fig. 1). Most of the triangles touch on one edge, some on one vertice. I would now like to generate a polygon shapefile containing the remaining triangles, dissolved into one polygon (of multiple rings, see fig. 2).
Fig 1. - TIN with some triangles removed. Vertices of touching triangles are exactly identical, no sliver polygons.
Fig. 2 - Note, that this is only one polygon with a single line in the attribute table
Pictures were made by using the QGIS "Vector-->Geoprocessing Tools-->Dissolve" tool.Is this possible with the ogr python bindings?Here's what I've tried so far:
from osgeo import ogrtri = ogr.Geometry(ogr.wkbLinearRing)tri.AddPoint(0,0)tri.AddPoint(0,1)tri.AddPoint(1,1)tri.CloseRings()poly = ogr.Geometry(ogr.wkbPolygon)poly.AddGeometry(tri)tri2 = ogr.Geometry(ogr.wkbLinearRing)tri2.AddPoint(1,1)tri2.AddPoint(0,1)tri2.AddPoint(0,4)poly2 = ogr.Geometry(ogr.wkbPolygon)poly2.AddGeometry(tri2)poly.Union(poly2) # returns Nonepoly.Intersect(poly2) # returns Falsepoly.Touches(poly2) # returns False (?)poly.Disjoint(poly2) # returns FalseI'm missing something like poly.Dissolve(), maybe used on a ogr.wkbGeometryCollection?
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Fig 1. - TIN with some triangles removed. Vertices of touching triangles are exactly identical, no sliver polygons.
Fig. 2 - Note, that this is only one polygon with a single line in the attribute table
Pictures were made by using the QGIS "Vector-->Geoprocessing Tools-->Dissolve" tool.Is this possible with the ogr python bindings?Here's what I've tried so far:
from osgeo import ogrtri = ogr.Geometry(ogr.wkbLinearRing)tri.AddPoint(0,0)tri.AddPoint(0,1)tri.AddPoint(1,1)tri.CloseRings()poly = ogr.Geometry(ogr.wkbPolygon)poly.AddGeometry(tri)tri2 = ogr.Geometry(ogr.wkbLinearRing)tri2.AddPoint(1,1)tri2.AddPoint(0,1)tri2.AddPoint(0,4)poly2 = ogr.Geometry(ogr.wkbPolygon)poly2.AddGeometry(tri2)poly.Union(poly2) # returns Nonepoly.Intersect(poly2) # returns Falsepoly.Touches(poly2) # returns False (?)poly.Disjoint(poly2) # returns FalseI'm missing something like poly.Dissolve(), maybe used on a ogr.wkbGeometryCollection?
أكثر...