<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;
font-size:11.0pt;
font-family:"Calibri",sans-serif;
mso-fareast-language:EN-US;}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Arial",sans-serif;
color:black;
font-weight:normal;
font-style:normal;
text-decoration:none none;}
.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]-->
</head>
<body lang="EN-GB" link="#0563C1" vlink="#954F72" style="word-wrap:break-word">
<div class="WordSection1">
<p class="MsoNormal"><span style="font-family:"Arial",sans-serif;color:black">I'm writing applications using the GDAL Python bindings and when I profile for performance, GetFeatureCount frequently comes out near the top. I'm often using it to check whether
a spatial or attribute filter has returned any features and don't need the full count. When the layer contains millions of features, there would be a big performance improvement if we could exit the count early.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Arial",sans-serif;color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Arial",sans-serif;color:black">Is there a better way of doing this? I've tried using GetNextFeature instead, but there must be quite a lot of overhead in that function as it is much slower. All I need to know is
if the layer has has 0, 1 or >1 features, I don't need the actual count. Can anyone suggest the fastest way of doing this in Python? I'm using GDAL 3.3.1 at the moment but could upgrade if there is new functionality that would help.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Arial",sans-serif;color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Arial",sans-serif;color:black">Thanks,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Arial",sans-serif;color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Arial",sans-serif;color:black">Jon<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Arial",sans-serif;color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-family:"Arial",sans-serif;color:#F6A124;mso-fareast-language:EN-GB">Jon Morris<o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span style="font-family:"Arial",sans-serif;color:#4A4A49;mso-fareast-language:EN-GB">Software Developer<o:p></o:p></span></b></p>
<p class="MsoNormal"><span style="font-family:"Arial",sans-serif;color:black;mso-fareast-language:EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div dir="ltr" style="mso-line-height-rule:exactly;-webkit-text-size-adjust:100%;direction:ltr;"><table cellpadding="0" cellspacing="0" border="0" style="width:100%;"><tr style="font-size:0;"><td align="left" style="vertical-align:top;"><table cellpadding="0" cellspacing="0" border="0" style="font-size:0;"><tr style="font-size:0;"><td align="left" style="padding:10px 0 0;vertical-align:top;"><table cellpadding="0" cellspacing="0" border="0" style="font-size:0;color:#4A4A49;font-style:normal;font-weight:700;white-space:nowrap;"><tr style="font-size:14.67px;"><td align="left" style="padding:0;vertical-align:top;font-family:Arial;">e: <span style="font-family:remialcxesans;font-size:1px;color:#FFFFFF;line-height:1px;"></span></td><td align="left" style="padding:0 0 0 4px;vertical-align:top;color:#F6A124;font-family:Arial;font-weight:400;"><a href="mailto:Jon.Morris@jbarisk.com" target="_blank" id="LPlnk689713" style="text-decoration:none;color:#F6A124;"><strong style="font-weight:400;">Jon.Morris@jbarisk.com</strong></a></td></tr><tr style="font-size:14.67px;"><td align="left" style="padding:0;vertical-align:top;font-family:Arial;">t: </td><td align="left" style="padding:0 0 0 4px;vertical-align:top;color:#F6A124;font-family:Arial;font-weight:400;"><a href="tel:+44%20(0)1756%20799919" target="_blank" id="LPlnk689713" style="text-decoration:none;color:#F6A124;"><strong style="font-weight:400;">+44 (0)1756 799919</strong></a></td></tr><tr style="font-size:0;"><td align="left" style="padding:0;vertical-align:top;"></td><td align="left" style="padding:0 0 0 4px;vertical-align:top;"></td></tr></table></td></tr></table></td></tr><tr style="color:#000001;font-size:14.67px;font-style:normal;font-weight:400;white-space:nowrap;"><td align="left" style="vertical-align:top;font-family:Arial;"><a href="http://www.jbarisk.com/" target="_blank" id="LPlnk689713" title="Click to visit our website" style="text-decoration:none;color:#F6A124;"><strong style="font-weight:400;">www.jbarisk.com</strong></a></td></tr><tr style="font-size:0;"><td align="left" style="vertical-align:top;"><table cellpadding="0" cellspacing="0" border="0" style="font-size:0;"><tr style="font-size:0;"><td align="left" style="padding:10px 0 0;vertical-align:top;"><table cellpadding="0" cellspacing="0" border="0" style="font-size:0;"><tr style="font-size:0;"><td rowspan="3" align="left" style="padding:0 0 5px;vertical-align:top;"><table cellpadding="0" cellspacing="0" border="0" style="width:100%;font-size:0;"><tr style="font-size:0;"><td align="left" style="vertical-align:top;"><table cellpadding="0" cellspacing="0" border="0" style="font-size:0;line-height:normal;"><tr style="font-size:0;"><td align="left" style="padding:10px 0 15px;vertical-align:top;"><img src="cid:image918956.png@E0217DE5.980DE59A" height="52" border="0" alt="" style="height:52px;min-height:52px;max-height:52px;font-size:0;" /></td></tr></table></td></tr><tr style="font-size:0;"><td align="left" style="vertical-align:top;"><table cellpadding="0" cellspacing="0" border="0" style="font-size:0;"><tr style="font-size:0;"><td align="left" style="padding:0 0 12px;vertical-align:top;"><table cellpadding="0" cellspacing="0" border="0" style="height:30px;font-size:0;"><tr style="font-size:0;"><td align="left" style="vertical-align:top;"><table cellpadding="0" cellspacing="0" border="0" style="font-size:0;line-height:normal;"><tr style="font-size:0;"><td align="left" style="padding:0 4px 5px 0;vertical-align:top;"><a href="https://www.facebook.com/TheFloodPeople" target="_blank" id="LPlnk689713" style="text-decoration:none;"><img src="cid:image215268.png@E195FCE0.5A9820EA" width="34" border="0" title="Facebook" alt="Facebook" style="width:34px;min-width:34px;max-width:34px;font-size:12px;" /></a></td></tr></table></td><td align="left" style="vertical-align:top;"><table cellpadding="0" cellspacing="0" border="0" style="font-size:0;line-height:normal;"><tr style="font-size:0;"><td align="left" style="padding:0 4px 5px 0;vertical-align:top;"><a href="https://www.linkedin.com/company/jba-risk-management/" target="_blank" id="LPlnk689713" style="text-decoration:none;"><img src="cid:image706640.png@34C8E1F4.A3CC55CF" width="34" border="0" title="LinkedIn" alt="LinkedIn" style="width:34px;min-width:34px;max-width:34px;font-size:12px;" /></a></td></tr></table></td><td align="left" style="vertical-align:top;"><table cellpadding="0" cellspacing="0" border="0" style="font-size:0;line-height:normal;"><tr style="font-size:0;"><td align="left" style="padding:0 4px 5px 0;vertical-align:top;"><a href="https://twitter.com/JBARisk" target="_blank" id="LPlnk689713" style="text-decoration:none;"><img src="cid:image011385.png@D0D92C04.B3691BC0" width="34" border="0" title="Twitter" alt="Twitter" style="width:34px;min-width:34px;max-width:34px;font-size:12px;" /></a></td></tr></table></td><td align="left" style="vertical-align:top;"><table cellpadding="0" cellspacing="0" border="0" style="font-size:0;line-height:normal;"><tr style="font-size:0;"><td align="left" style="padding:0 4px 5px 0;vertical-align:top;"><a href="https://www.youtube.com/channel/UC0iatom2jYbW96voW0rlpCw" target="_blank" id="LPlnk689713" style="text-decoration:none;"><img src="cid:image866509.png@76A36F87.7B805C0F" width="34" border="0" title="YouTube" alt="YouTube" style="width:34px;min-width:34px;max-width:34px;font-size:12px;" /></a></td></tr></table></td></tr></table></td></tr></table></td></tr></table></td><td style="padding:0;"> </td></tr><tr style="font-size:0;"><td style="padding:0;"> </td></tr><tr style="font-size:0;"><td style="padding:0;"> </td></tr></table></td></tr></table></td></tr><tr style="font-size:0;"><td align="left" style="vertical-align:top;"><table cellpadding="0" cellspacing="0" border="0" style="font-size:0;"><tr style="font-size:0;"><td align="left" style="padding:7px 0 5px;border-top:solid 1px #4A4A49;border-right:none;border-bottom:none;border-left:none;vertical-align:top;"><table cellpadding="0" cellspacing="0" border="0" style="white-space:normal;color:#444444;font-size:14.67px;font-family:Calibri,Arial,sans-serif;font-weight:400;font-style:normal;text-align:left;line-height:12px;"><tr style="font-size:9px;"><td style="font-family:Arial;"><span style="background-color:#FFFFFF;">All JBA Risk Management's email messages contain confidential information and are intended only for the individual(s) named. If you are not the named addressee you should not disseminate, distribute or copy this e-mail.</span><br /><span style="background-color:#FFFFFF;">Please notify the sender immediately by email if you have received this email by mistake and delete this email from your system.</span> <br /><span style="background-color:#FFFFFF;">JBA Risk Management Limited is registered in England, company number 07732946, 1 Broughton Park, Old Lane North, Broughton, Skipton, North Yorkshire, BD23 3FD, England</span><span style="color:#000001;">.</span><br /></td></tr></table></td></tr></table></td></tr></table></div></body>
</html>