[Qgis-user] Looking for application/server etc

[chris hermansen]

Dennis and list;

On Thu, Jan 12, 2023 at 8:45 AM Dennis Burgess via QGIS-User <
qgis-user at lists.osgeo.org> wrote:

> But looking to only display what is on the customer screen.  We should
> never get the 50 meg poly..
>
> <qgis-user at lists.osgeo.org>
> *Subject:* RE: Looking for application/server etc
>
> [stuff deleted]

>
>
> PostGIS with Geometry Index’s?!
>
> Set up Styles with Zoom Levels so as when zoomed in to 1:5000, that’s the
> only time you have full LOD
>


> [stuff deleted]
>
> <https://www.opw.ie/en/disclaimer/>
>


> *From:* QGIS-User <qgis-user-bounces at lists.osgeo.org> *On Behalf Of *Dennis
> Burgess via QGIS-User
> *Sent:* 12 January 2023 15:43
> *To:* qgis-user at lists.osgeo.org
> *Subject:* [Qgis-user] Looking for application/server etc
>
>
>
> Looking for something that can take a HUGE, say a 50-75 meg mutli-polygon
> (multi-state etc.), that has detail level down to 1meter, then parse it and
> display it within 1meg on top of mapping systems in a web browser ?
> Options?  Not to mention, we have a few thousand of these so we need to be
> able to call the mapping for any one of them.   We also need it to simplify
> it i.e. maybe deliver a max a 1 meg to the customer..  if they zoom out we
> want to make it simpler to deliver something to the customer..  I’m sure
> there is a way of doing this..
>
>
>
> I’m sure there is an application, server, something that can do this
> automatically..
>
>
>
Dennis, do you mean your object of interest is a MULTIPOLYGON?  Because if
so, your bounding box, and therefore your spatial index, is going to bound
the entire polygon, and that's going to limit any kind of efficiency as you
zoom in.

You might consider splitting your MULTIPOLYGON into POLYGONs.  That way
each POLYGON will have its own bounding box and therefore your spatial
indexing scheme will have the chance to be more efficient.  But of course
you have to watch out for polygons like the Mississippi River.

This article might help
https://www.alibabacloud.com/blog/postgresql-how-to-optimize-spatial-index-based-query-performance-for-multipolygon-data_597324

I agree with Richard; PostGIS provides nice geometry indexing.  Probably
other database managers do as well.

I'm not certain that I follow what you are doing precisely, but one kind of
architecture would be to have your database within PostgreSQL / PostGIS,
being accessed by QGIS server and delivered to your clients that way.

The QGIS server guide is here
https://docs.qgis.org/3.22/en/docs/server_manual/index.html

The PostGIS manual is here https://postgis.net/documentation/

There are many, many resources available to learn PostGIS.  From personal
experience I know this is a good one
https://www.manning.com/books/postgis-in-action-third-edition

-- 
Chris Hermansen · clhermansen "at" gmail "dot" com

C'est ma façon de parler.
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