I have a shape that looks like this: enter image description here

It's the end result of a buffer, merge, bugffer and Chaikin Smoothing process in PostGIS. It's almost perfect however I'd like to remove some of the "fissures". If I could get the shape to have the boundary like the red line below it would be great. Ideally something I can do in postGIS.

enter image description here Any thought?


There is a function made exactly for this problem: ST_ConcaveHull

ST_Simplify can work, but it is not exactly the best option depending of the situation (it's not really what it's made for, and you will easily lose the details of the boundaries of your polygone while still having holes).

  • Thanks, I'll give it a try tomorrow when I'm back at work. – Omar Sarhan Mar 21 at 20:20
  • If you want you can also use it directly on your geometries for exemple with st_union (instead of the buffer/merge... process) and then maybe a buffer (dpending of your original problem) – robin loche Mar 22 at 21:37

Cleaning it up with ST_Simplify or ST_SimplifyPreserveTopology should do that.


One of the solutions to your problem

Create an external buffer by running the script:

create table table_buf_exter as SELECT ST_Buffer((ST_MakePolygon(ST_ExteriorRing(ST_Buffer((geom),0.007)))),-0.007) geom FROM source_table

Set the value of the buffer, so that they cover the width of the fine parts.

good luck in good deeds ...

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