<div dir="auto">We're still at least a month out from having PostGIS code to release, but once it's out feedback will be appreciated. </div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Jul 3, 2019, 8:21 AM Giunta Igor <<a href="mailto:Igor.Giunta@tg.ch">Igor.Giunta@tg.ch</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Thanx Martin<u></u><u></u></span></p>
<p class="MsoNormal"><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?<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="FR-CH" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p>
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<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 <<a href="mailto:postgis-users-bounces@lists.osgeo.org" target="_blank" rel="noreferrer">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" rel="noreferrer">postgis-users@lists.osgeo.org</a>><br>
<b>Betreff:</b> Re: [postgis-users] PostGIS new geometry type with defined precision?<u></u><u></u></span></p>
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<p class="MsoNormal">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. <u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">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.<u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">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 <u></u><u></u></p>
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<p class="MsoNormal">On Wed, Jul 3, 2019, 5:48 AM Darafei "Komяpa" Praliaskouski <<a href="mailto:me@komzpa.net" target="_blank" rel="noreferrer">me@komzpa.net</a>> wrote:<u></u><u></u></p>
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<p class="MsoNormal">Hi,<u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">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?<u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">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.<u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">On Wed, Jul 3, 2019 at 2:43 PM Giunta Igor <<a href="mailto:Igor.Giunta@tg.ch" target="_blank" rel="noreferrer">Igor.Giunta@tg.ch</a>> wrote:<u></u><u></u></p>
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<p class="MsoNormal">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>
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I guess we are not the first users facing this problem.<br>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">-- <u></u><u></u></p>
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<p class="MsoNormal">Darafei Praliaskouski<u></u><u></u></p>
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<p class="MsoNormal">Support me: <a href="http://patreon.com/komzpa" target="_blank" rel="noreferrer">
http://patreon.com/komzpa</a><u></u><u></u></p>
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