[postgis-users] soft breaklines (constrained delaunay)

Donovan Cameron sault.don at gmail.com
Tue Aug 10 15:38:29 PDT 2021

I've been searching for a method to generate a TIN from three inputs, 
including soft breaklines that don't have a z-value:

1.) Contour (3d line)
2.) height point (3d point)
3.) soft breakline (2d line)

Inputs 1 and 2 have z-values in ELEVATION column, whereas input 3 has no 
z-value and is used to maintain those edge type features in the 
resulting TIN/DEM.

The soft breaklines represent features like lake edges, streams, roads, 
and other 'edge' type features in the TIN.

I have some sample data I could get together to share if needed.

I've done it in the past using v.triangle[1] from GRASS GIS.

Constrained Delaunay Triangles [2] are part of the underlying theory I 
think when computing these with soft breaklines.


[1] https://grasswiki.osgeo.org/wiki/TIN_with_breaklines

[2] http://postgis.net/docs/ST_ConstrainedDelaunayTriangles.html

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