<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;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:#0563C1;
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]-->
</head>
<body lang="EN-GB" link="#0563C1" vlink="#954F72" style="word-wrap:break-word">
<div class="WordSection1">
<p class="MsoNormal">I am trying to put together the 50m uk DEM e.g. <a href="https://www.data.gov.uk/dataset/835cf20a-8feb-4394-8b30-dcfe840ac13d/os-terrain-50-dtm">
https://www.data.gov.uk/dataset/835cf20a-8feb-4394-8b30-dcfe840ac13d/os-terrain-50-dtm</a> but it often does not work. The data are supplied as thousands of small tiles that takes ages to unpack and put into a folder to get into qgis, however when you try
to load the tiles some work and others don’t and even the ones that do work and display fine sometimes don’t merge to form large tiles and sometimes will form virtual rasters but not merged files. Basically it is a mess. I suspect others have done this successfully
so any suggestions?<o:p></o:p></p>
<p class="MsoNormal">It is particularly odd that some of the tiles will merge and others won’t and that some won’t display if you ask it to load hundreds at a time but if you just add them in a few at a time then they will load and display (in addition to the
hundreds already loaded). This suggests various bugs assuming the original data are not in a whole variety of slightly different formats (should all be .asc)<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
</body>
</html>