[postgis-users] Creating a boundary of an aggregate of buildings

[Hugues François]

Hi,

Some time ago, I wrote a PLPGSQL function that creates urban areas from a buildings table.

The attached function could help you to solve your issues and test several thresholds when adapted to your own database. I'm sorry it's written in a weird French-English style but the queries should help you to understand the variable names meaning. Of course, feel free to ask any question.

The hole issue is directly adressed line 55 to line 85. It uses st_dumprings along with st_exterrioring and st_buildarea and compares hole surface to the "surf_trou" threshold.

HTH,
Hug


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----- Mail original -----
De: "Luca Bertoncello" <lucabert at lucabert.de>
À: "PostGIS Users Discussion" <postgis-users at lists.osgeo.org>
Envoyé: Lundi 18 Janvier 2021 21:37:44
Objet: Re: [postgis-users] Creating a boundary of an aggregate of buildings

Am 18.01.2021 um 15:09 schrieb Tomas Straupis:
> I've tested on Vilnius and get fine results with coefficients given
> below (but for you numbers could be different depending on which is
> your target scale).

Hi again,

I think I'm on the right way...
I can select the boundaries by size, so I can display almost what I need.
The very problem is that I have many "holes"...

You can see the example: in Dresden there are many holes in the
building, but they are "little", and I want to fill them, leaving the
holes greater than X...

Do you have an idea how to do that?

Thanks
Luca Bertoncello
(lucabert at lucabert.de)


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