So, while wondering about shape simplification in the eternal struggle for optimization, I find out (here on SE) that Geoserver and PostGIS can and will (by default) perform the trick on the fly (see Small features don't draw when zoomed out using Geoserver WMS), all by themselves.

A number of questions come to mind (does it work with shapefiles too ? at which point of the process does it happen ? obviously the renderer must simplify the shape in any case, simply because of available pixels - but does a non-simplified shape that gets simplified on rendering have the same weight resource-wise as one that's pre-simplified ?), but to pick one:

how much of a resource hit is it, compared to preparing simplified versions of the geometries beforehand ?

The spider sense says it should be significant, but Geoserver has surprised me several times already in the brief time we have known each other.

1 Answer 1


As you note this is a default option for PostGIS datastores where the work can be offloaded to the database. So it is not available by default for other stores.

But there is a pre-generalized datastore that you can add to GeoServer which will do something similar using a collection of generalised shapefiles. There is a (pre-2.0) tutorial that may help you get started.

  • Not the actual question, but good job answering all the others in one go.
    – deg
    Aug 30, 2017 at 15:11
  • your actual question is pretty much impossible to answer for anything but a specific dataset and styling combo
    – Ian Turton
    Aug 30, 2017 at 15:16
  • I agree, and I should edit it as soon as I figure out a way to do it that makes sense in human. I am trying to figure it out in terms of negligible/unconcerning/significant/crippling, within the given terms of comparison. Of course, finding that that job is given to the database entirely already half knocks the question out, as it seems like a type of task the db would be comfortable with.
    – deg
    Aug 30, 2017 at 15:31
  • I suppose the bottom line is "should I bother in general ?".
    – deg
    Aug 30, 2017 at 15:31

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