Hi Martin
I just found some exchanges here:
http://osgeo-org.1560.x6.nabble.com/Fixed-precision-for-ST-Intersection-ST-Union-etc-td5255487.html
In the meanwhile GEOS3.6 has been sent out with GEOSGeom_{set,get}Precision
according to
http://osgeo-org.1560.x6.nabble.com/GEOS-3-6-0-released-td5292606.html
On the PostGIS side I don't find any correspndance.
Is your work going to integrate this GEOS functions into PosGIS or your
approach is independent?
Von: postgis-users <[email protected]> Im Auftrag von
Martin Davis
Gesendet: Mittwoch, 3. Juli 2019 18:02
An: PostGIS Users Discussion <[email protected]>
Betreff: Re: [postgis-users] PostGIS new geometry type with defined precision?
We're still at least a month out from having PostGIS code to release, but once
it's out feedback will be appreciated.
On Wed, Jul 3, 2019, 8:21 AM Giunta Igor
<[email protected]<mailto:[email protected]>> wrote:
Thanx Martin
it sounds promising.. can we somehow give any help at this conceptual stage?
Von: postgis-users
<[email protected]<mailto:[email protected]>>
Im Auftrag von Martin Davis
Gesendet: Mittwoch, 3. Juli 2019 16:54
An: PostGIS Users Discussion
<[email protected]<mailto:[email protected]>>
Betreff: Re: [postgis-users] PostGIS new geometry type with defined precision?
JTS already provided a mechanism to specify a precision for geometry, and this
is respected by a number of operations as well (notably the overlay operations
intersection et al and buffer - but not the spatial predicates, yet). GEOS
should provide this as well, or is close to doing so. And I'm currently
working on a new implementation of overlay to improve robustness, which will
improve fixed precision computation as well.
The issue of handling fixed precision for predicates is a good question. I
have an algorithm in the conceptual stages for this. But it may be difficult
to make it consistent with the overlay operations on a performant way. I
intend to write up a survey of the options soon.
My current thinking is that precision will be specified as a parameter to
geometry operations. No new type will be required. It might be nice to have
precision specified in column metadata somehow, but not sure how this could work
On Wed, Jul 3, 2019, 5:48 AM Darafei "Komяpa" Praliaskouski
<[email protected]<mailto:[email protected]>> wrote:
Hi,
Can you describe how the operations like Intersection should behave in such
type? E.g. if you have a type with 0 decimals (say), and have a line going from
(0,0) to (1,1) intersect with a line going from (1, 0) to (0, 1) - what is the
intersection point that is going to be reported? Will that ST_Intersection in
turn ST_Intersects=true with original point?
There are a number of such requests across the years but nobody seems to
propose a working algebra for such type, and without it it's not going to get
implemented.
On Wed, Jul 3, 2019 at 2:43 PM Giunta Igor
<[email protected]<mailto:[email protected]>> wrote:
How can a precision be assigned to a geometry, e.g. a point/line/polygon to 3
decimals, in order that any input/output will be given in that precision
(without usage of rounding functions like snap2grid)
How can the problem be tackeld? Shall we request to include new types? Or shall
we rather let develop a new feature?
I guess we are not the first users facing this problem.
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Darafei Praliaskouski
Support me: http://patreon.com/komzpa
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