<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta name="Generator" content="Microsoft Word 15 (filtered medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman",serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph
{mso-style-priority:34;
margin-top:0cm;
margin-right:0cm;
margin-bottom:0cm;
margin-left:36.0pt;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman",serif;}
p.msonormal0, li.msonormal0, div.msonormal0
{mso-style-name:msonormal;
mso-margin-top-alt:auto;
margin-right:0cm;
mso-margin-bottom-alt:auto;
margin-left:0cm;
font-size:12.0pt;
font-family:"Times New Roman",serif;}
span.E-MailFormatvorlage18
{mso-style-type:personal-reply;
font-family:"Calibri",sans-serif;
color:#1F497D;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:70.85pt 70.85pt 2.0cm 70.85pt;}
div.WordSection1
{page:WordSection1;}
/* List Definitions */
@list l0
{mso-list-id:1390885205;
mso-list-type:hybrid;
mso-list-template-ids:1374205712 1592136282 134676505 134676507 134676495 134676505 134676507 134676495 134676505 134676507;}
@list l0:level1
{mso-level-text:"%1\)";
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;
mso-ansi-language:DE-CH;}
@list l0:level2
{mso-level-number-format:alpha-lower;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;}
@list l0:level3
{mso-level-number-format:roman-lower;
mso-level-tab-stop:none;
mso-level-number-position:right;
text-indent:-9.0pt;}
@list l0:level4
{mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;}
@list l0:level5
{mso-level-number-format:alpha-lower;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;}
@list l0:level6
{mso-level-number-format:roman-lower;
mso-level-tab-stop:none;
mso-level-number-position:right;
text-indent:-9.0pt;}
@list l0:level7
{mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;}
@list l0:level8
{mso-level-number-format:alpha-lower;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;}
@list l0:level9
{mso-level-number-format:roman-lower;
mso-level-tab-stop:none;
mso-level-number-position:right;
text-indent:-9.0pt;}
ol
{margin-bottom:0cm;}
ul
{margin-bottom:0cm;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="DE-CH" link="blue" vlink="purple">
<div class="WordSection1">
<p class="MsoNormal"><span lang="FR-CH" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Hi Darafei and Paul<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">thanx for your feedback. I see your points for those "clinical cases", but let me answer like this:<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="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><span style="mso-list:Ignore">1)<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">concernig
</span><span lang="FR-CH" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">bugous
</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">intersection: the result will always be uncertain beyond resolution. Consider the same situation with 10 digit resolution. you won't be able to say
which one among the 4 pixel around the matematical point is the right one. Fortunately at this scale it doesn't matter for most GIS-applications, but in principle it WILL for some (e.g. at the CERN in Geneva, where the alignement scales goes from km down to
nanometers).<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><span style="mso-list:Ignore">2)<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="FR-CH" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">concerning bugous distance: beyond the resolution *<b>per definition</b>* you may not speak about distinct points;
it thenmakes no sense to measure their distance.<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><span style="mso-list:Ignore">3)<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">floatings numbers are always stored as integers on the disk…<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"><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>
<div>
<div style="border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm">
<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>Paul Ramsey<br>
<b>Gesendet:</b> Mittwoch, 3. Juli 2019 16:35<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>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Also, what are the results of ST_Distance() when the distance is < tolerance? Zero? Tolerance?<o:p></o:p></p>
<div>
<p class="MsoNormal">Basically tolerance is a cross-cutting concern that affects almost every function in the system, sometimes in ways that ordinary users might consider “surprising” or “counter intuitive”. Our current “as much precision as we can take” system
still has wonderful corner cases since we don’t actually have infinite precision at our command: the results of ST_Intersection(A, B) does not necessarily ST_Intersects() A or B.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal">The new overlay work in GEOS requires explicit precision, so we are going to start inching in that direction over time. Until then, enforcing precision on insert/update with triggers is not the end of the world if you want command of your
precision model.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal">ATB,<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal">P<o:p></o:p></p>
<div>
<p class="MsoNormal"><br>
<br>
<o:p></o:p></p>
<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<div>
<p class="MsoNormal">On Jul 3, 2019, at 5:47 AM, Darafei Komяpa Praliaskouski <<a href="mailto:me@komzpa.net">me@komzpa.net</a>> wrote:<o:p></o:p></p>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<div>
<p class="MsoNormal">Hi,<o:p></o:p></p>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<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?<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<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.<o:p></o:p></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<div>
<p class="MsoNormal">On Wed, Jul 3, 2019 at 2:43 PM Giunta Igor <<a href="mailto:Igor.Giunta@tg.ch">Igor.Giunta@tg.ch</a>> wrote:<o:p></o:p></p>
</div>
<blockquote style="border:none;border-left:solid #CCCCCC 1.0pt;padding:0cm 0cm 0cm 6.0pt;margin-left:4.8pt;margin-right:0cm">
<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>
<br>
I guess we are not the first users facing this problem.<br>
<br>
<br>
_______________________________________________<br>
postgis-users mailing list<br>
<a href="mailto:postgis-users@lists.osgeo.org" target="_blank">postgis-users@lists.osgeo.org</a><br>
<a href="https://lists.osgeo.org/mailman/listinfo/postgis-users" target="_blank">https://lists.osgeo.org/mailman/listinfo/postgis-users</a><o:p></o:p></p>
</blockquote>
</div>
<p class="MsoNormal"><br clear="all">
<o:p></o:p></p>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<p class="MsoNormal">-- <o:p></o:p></p>
<div>
<div>
<div>
<div>
<p class="MsoNormal">Darafei Praliaskouski<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal">Support me: <a href="http://patreon.com/komzpa" target="_blank">
http://patreon.com/komzpa</a><o:p></o:p></p>
</div>
</div>
</div>
</div>
<p class="MsoNormal">_______________________________________________<br>
postgis-users mailing list<br>
<a href="mailto:postgis-users@lists.osgeo.org">postgis-users@lists.osgeo.org</a><br>
<a href="https://lists.osgeo.org/mailman/listinfo/postgis-users">https://lists.osgeo.org/mailman/listinfo/postgis-users</a><o:p></o:p></p>
</div>
</blockquote>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
</div>
</body>
</html>