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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Hi Martin<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">I just found some exchanges here:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><a href="http://osgeo-org.1560.x6.nabble.com/Fixed-precision-for-ST-Intersection-ST-Union-etc-td5255487.html">http://osgeo-org.1560.x6.nabble.com/Fixed-precision-for-ST-Intersection-ST-Union-etc-td5255487.html</a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">In the meanwhile GEOS3.6 has been sent out with GEOSGeom_{set,get}Precision according to
<o:p></o:p></span></p>
<p class="MsoNormal" style="text-align:justify"><span lang="FR-CH" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><a href="http://osgeo-org.1560.x6.nabble.com/GEOS-3-6-0-released-td5292606.html">http://osgeo-org.1560.x6.nabble.com/GEOS-3-6-0-released-td5292606.html</a><o:p></o:p></span></p>
<p class="MsoNormal" style="text-align:justify"><span lang="FR-CH" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal" style="text-align:justify"><span lang="FR-CH" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">On the PostGIS side I don't find any correspndance.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="FR-CH" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Is your work going to integrate this GEOS functions into PosGIS or your approach is independent?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="FR-CH" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="FR-CH" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="FR-CH" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span lang="DE" style="font-size:11.0pt;font-family:"Calibri",sans-serif">Von:</span></b><span lang="DE" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> postgis-users <postgis-users-bounces@lists.osgeo.org>
<b>Im Auftrag von </b>Martin Davis<br>
<b>Gesendet:</b> Mittwoch, 3. Juli 2019 18:02<br>
<b>An:</b> PostGIS Users Discussion <postgis-users@lists.osgeo.org><br>
<b>Betreff:</b> Re: [postgis-users] PostGIS new geometry type with defined precision?<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">We're still at least a month out from having PostGIS code to release, but once it's out feedback will be appreciated. <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">On Wed, Jul 3, 2019, 8:21 AM Giunta Igor <<a href="mailto:Igor.Giunta@tg.ch">Igor.Giunta@tg.ch</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Thanx Martin</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="FR-CH" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">it sounds promising.. can we somehow give any help at this conceptual stage?</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="FR-CH" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="FR-CH" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><b><span lang="DE" style="font-size:11.0pt;font-family:"Calibri",sans-serif">Von:</span></b><span lang="DE" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> postgis-users
<<a href="mailto:postgis-users-bounces@lists.osgeo.org" target="_blank">postgis-users-bounces@lists.osgeo.org</a>>
<b>Im Auftrag von </b>Martin Davis<br>
<b>Gesendet:</b> Mittwoch, 3. Juli 2019 16:54<br>
<b>An:</b> PostGIS Users Discussion <<a href="mailto:postgis-users@lists.osgeo.org" target="_blank">postgis-users@lists.osgeo.org</a>><br>
<b>Betreff:</b> Re: [postgis-users] PostGIS new geometry type with defined precision?</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">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. <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">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.<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">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 <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">On Wed, Jul 3, 2019, 5:48 AM Darafei "Komяpa" Praliaskouski <<a href="mailto:me@komzpa.net" target="_blank">me@komzpa.net</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Hi,<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">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?<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">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.<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">On Wed, Jul 3, 2019 at 2:43 PM Giunta Igor <<a href="mailto:Igor.Giunta@tg.ch" target="_blank">Igor.Giunta@tg.ch</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">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)<br>
How can the problem be tackeld? Shall we request to include new types? Or shall we rather let develop a new feature?<br>
<br>
I guess we are not the first users facing this problem.<br>
<br>
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<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Darafei Praliaskouski<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Support me:
<a href="http://patreon.com/komzpa" target="_blank">http://patreon.com/komzpa</a><o:p></o:p></p>
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