<html>
<head>
<meta http-equiv="Content-Type" content="text/html;
charset=windows-1252">
</head>
<body text="#000000" bgcolor="#FFFFFF">
<p>Matthew,</p>
<p>The documentation(1) says "The result layer contains features
whose geometries represent areas that are either in the input
layer, in the method layer, or in both.". I assume you a polygon
in the input layer B which has a common singular point and common
area with a polygon in layer C.</p>
<p>Ari<br>
</p>
<p>(1)
<a class="moz-txt-link-freetext" href="http://gdal.org/classOGRLayer.html#adf0598c7dab1f4dbe3e2735e27450c9c">http://gdal.org/classOGRLayer.html#adf0598c7dab1f4dbe3e2735e27450c9c</a><br>
</p>
<br>
<div class="moz-cite-prefix">On 12.02.2018 11:58, Matthew Snape
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:HE1PR0701MB22523AB44C6C5FCF55DC97C3BFF70@HE1PR0701MB2252.eurprd07.prod.outlook.com">
<meta http-equiv="Content-Type" content="text/html;
charset=windows-1252">
<meta name="Generator" content="Microsoft Word 14 (filtered
medium)">
<style><!--
/* Font Definitions */
@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:11.0pt;
font-family:"Calibri","sans-serif";
mso-fareast-language:EN-US;}
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;}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Calibri","sans-serif";
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-family:"Calibri","sans-serif";
mso-fareast-language:EN-US;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:72.0pt 72.0pt 72.0pt 72.0pt;}
div.WordSection1
{page:WordSection1;}
--></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]-->
<div class="WordSection1">
<p class="MsoNormal">Hello,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I am performing a union of two layers using
OGR from Python…<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">layerA.Union(layerB,
layerC,["PROMOTE_TO_MULTI=YES",])<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">This returns a layer composed of
multipolygon’s except for a single geometrycollection in the
form…<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">GEOMETRYCOLLECTION (POINT (2610469.66
3325023.52),POLYGON ((2610439.3657 3325014.925899999……….<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Is this expected behaviour, and if so what
is it showing?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Any help appreciated<o:p></o:p></p>
<p class="MsoNormal">Thank you.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<meta name="GENERATOR" content="MSHTML 11.00.9600.18283">
<p><font size="1" face="Arial" color="#003366">This e-mail message
and any attached file is the property of the sender and is
sent in confidence to the addressee only.</font></p>
<p><font size="1" face="Arial" color="#003366">Internet
communications are not secure and RPS is not responsible for
their abuse by third parties, any alteration or corruption in
transmission or for any loss or damage caused by a virus or by
any other means.</font></p>
<p><font size="1" face="Arial" color="#003366">RPS Group Plc,
company number: 208 7786 (England). Registered office: 20
Western Avenue Milton Park Abingdon Oxfordshire OX14 4SH.<br>
<br>
RPS Group Plc web link: <a href="http://www.rpsgroup.com/"
moz-do-not-send="true">http://www.rpsgroup.com</a></font></p>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
<pre wrap="">_______________________________________________
gdal-dev mailing list
<a class="moz-txt-link-abbreviated" href="mailto:gdal-dev@lists.osgeo.org">gdal-dev@lists.osgeo.org</a>
<a class="moz-txt-link-freetext" href="https://lists.osgeo.org/mailman/listinfo/gdal-dev">https://lists.osgeo.org/mailman/listinfo/gdal-dev</a></pre>
</blockquote>
<br>
</body>
</html>