<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=iso-8859-1">
<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:11.0pt;
font-family:"Calibri",sans-serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:#0563C1;
text-decoration:underline;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@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="FI" link="#0563C1" vlink="#954F72">
<div class="WordSection1">
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Hi Even,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">You working with NLS sounds really wonderful! This is great news :-)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">Is there somewhere I could follow progress on this? Is there any way I could help to make this happen?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">I agree with your comment about plugins. But still, sometimes they would be very handy. :-)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">- Oskari<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="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="EN-US">From:</span></b><span lang="EN-US"> Even Rouault <even.rouault@spatialys.com>
<br>
<b>Sent:</b> keskiviikko 17. kesäkuuta 2020 14.05<br>
<b>To:</b> proj@lists.osgeo.org<br>
<b>Cc:</b> Oskari Timperi <oskari.timperi@novatron.fi><br>
<b>Subject:</b> Re: [PROJ] Finnish KKJ with triangle-wise affine transformation<o:p></o:p></span></p>
</div>
</div>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt"><span style="font-size:9.0pt;font-family:"Courier New"">Oskari,<o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-paragraph-type:empty;-qt-block-indent:0">
<span style="font-size:9.0pt;font-family:"Courier New""> <o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New"">> In many places we still need to support the old KKJ (EPSG:2393) system. The<o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New"">> National Land Survey of Finland (Maanmittauslaitos) provides a TIN network<o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New"">> and affine transformation for each triangle for converting between<o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New"">> ETRS-TM35FIN and KKJ. This is the preferred and most accurate way to<o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New"">> convert to and from KKJ. More information and the plain text data files can<o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New"">> be found from NLS website though only in Finnish but you should be able to<o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New"">> get the idea<o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New"">>
<a href="https://www.maanmittauslaitos.fi/kartat-ja-paikkatieto/asiantuntevalle-kayt">
https://www.maanmittauslaitos.fi/kartat-ja-paikkatieto/asiantuntevalle-kayt</a><o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New"">> tajalle/koordinaattimuunnokset<o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New"">>
<o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New"">> My question is, is this kind of transformation something that could be<o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New"">> implemented inside PROJ at some point in the future? I don't know if this<o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New"">> kind of thing is used anywhere else so it might be that this has very<o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New"">> little use outside of Finland.<o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-paragraph-type:empty;-qt-block-indent:0">
<span style="font-size:9.0pt;font-family:"Courier New""> <o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New"">I'm currently working with National Land Survey of Finland to bring those transformations into PROJ. So stay tuned. Should
come in coming weeks / months. Triangulation-based transformations are likely of interest in other cases too as a number of grid-based transformations come initially from triangulations.<o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-paragraph-type:empty;-qt-block-indent:0">
<span style="font-size:9.0pt;font-family:"Courier New""> <o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New"">> If this isn't viable, are there any plans about plugin support for PROJ? It<o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New"">> would be cool to be able to implement custom steps and represent them as<o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New"">> part of the normal PROJ pipeline to implement special needs :-)<o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-paragraph-type:empty;-qt-block-indent:0">
<span style="font-size:9.0pt;font-family:"Courier New""> <o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New"">I can see pros & cons to a plugin approach. From a community point of view, plugins tend to "isolate" people. Sometimes what
one thinks to be a custom need can be useful for others.<o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-paragraph-type:empty;-qt-block-indent:0">
<span style="font-size:9.0pt;font-family:"Courier New""> <o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New"">Even<o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-paragraph-type:empty;-qt-block-indent:0">
<span style="font-size:9.0pt;font-family:"Courier New""> <o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New"">--
<o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New"">Spatialys - Geospatial professional services<o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New""><a href="http://www.spatialys.com">http://www.spatialys.com</a><o:p></o:p></span></p>
</div>
</body>
</html>