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</o:shapelayout></xml><![endif]--><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Hi Marco,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Thanks for such a quick reply. I can certainly send along a copy of the raster – it is a public source – but let me get approval from management before sending a vector layer to you (not a public source).<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I’ll hope to hear back from them tomorrow and perhaps send both layers together; if not, I’ll aim for Monday to get you some samples of some sort. I’ll also work on getting an updated build to try (hadn’t thought of that yet – good to know there are improvements in the tool already).<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Thanks for your help!<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><br>Jason<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Marco Hugentobler-4 [via OSGeo.org] [mailto:<a href="/user/SendEmail.jtp?type=node&node=5017075&i=0" target="_top" rel="nofollow" link="external">[hidden email]</a>] <br><b>Sent:</b> Friday, November 16, 2012 11:39 PM<br><b>To:</b> jasperfs<br><b>Subject:</b> Re: Zonal statistics behaviour<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Hi Jason <br><br>Can you share sample data (or send it to me privately if it is not public)? <br><br>>(in v1.8.0) <br><br>I've recently fixed a bug in the zonal statistics code, but I think it <br>was something different (out of raster bounds problem). Also, the <br>performance for large data set has improved considerably with that <br>commit, so you might try a recent nightly build. <br><br>Regards, <br>Marco <br><br>On 17.11.2012 03:20, jasperfs wrote: <o:p></o:p></p><div><p class=MsoNormal><div class='shrinkable-quote'><br>> Hi there, (first-time poster here - please excuse me if this is the wrong <br>> place for this topic) <br>> <br>> Your posting might be an indirect confirmation of (similar?) problems we <br>> have discovered in the past few days - our first experience using Zonal <br>> Statistics tool (in v1.8.0). <br>> <br>> Our goal is to compute mean areal values over polygons from a raster layer. <br>> In this first attempt with the tool, the pixels of our raster layer are <br>> larger than the polygon areas (e.g, 5-10 polygons fit within a pixel). When <br>> spot checking the mean output values, most of them *seem* to be correct <br>> except for occasional erroneous values that are easy to spot - that is, <br>> polygons that fall within in an area of all-zero pixels but still report a <br>> non-zero mean value (means such as 0.02, 0.3, 2.19, etc.). It is not easy <br>> to detect if similar errors are occurring in the non-zero areas as well. <br>> <br>> There is no obvious pattern to the occurrence based our initial experiments <br>> except that they seem to occur primarily within basins that fall on or very <br>> near the corner-intersection of four pixels. (In case that helps someone's <br>> diagnostics.) <br>> <br>> Because of these errors, we cannot use the tool for our intended purpose <br>> (compute mean areal precipitation over subcatchments) - but it would be a <br>> **HUGE** benefit to us, both in our training and operational purposes to <br>> incorporate additional forecasting data sets this way; it is such a simple <br>> solution, if only it produced correct results. <br>> <br>> We very much would like to see this tool work. <br>> <br>> Anyway... this report might be another "hit" to help identify the problem <br>> (if there actually is one) and get it fixed. (please, please) <br>> <br>> Thanks for your post, it helps to find some sort of confirmation to the <br>> issue. <br>> <br>> Best regards, <br>> <br>> Jason <br>> <br>> <<a href="" target="_top" rel="nofollow" link="external">click here</a>.<br><a href="http://osgeo-org.1560.n6.nabble.com/template/NamlServlet.jtp?macro=macro_viewer&id=instant_html%21nabble%3Aemail.naml&base=nabble.naml.namespaces.BasicNamespace-nabble.view.web.template.NabbleNamespace-nabble.view.web.template.NodeNamespace&breadcrumbs=notify_subscribers%21nabble%3Aemail.naml-instant_emails%21nabble%3Aemail.naml-send_instant_email%21nabble%3Aemail.naml" target="_top" rel="nofollow" link="external"><span style='font-size:7.0pt;font-family:"Times New Roman","serif"'>NAML</span></a> <o:p></o:p></span></p></div></div>
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