<html 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:0in;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
h3
{mso-style-priority:9;
mso-style-link:"Heading 3 Char";
mso-margin-top-alt:auto;
margin-right:0in;
mso-margin-bottom-alt:auto;
margin-left:0in;
font-size:13.5pt;
font-family:"Calibri",sans-serif;
font-weight:bold;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
span.Heading3Char
{mso-style-name:"Heading 3 Char";
mso-style-priority:9;
mso-style-link:"Heading 3";
font-family:"Calibri Light";
color:#1F3763;}
span.EmailStyle21
{mso-style-type:personal-reply;
font-family:"Calibri",sans-serif;
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style>
</head>
<body lang="EN-US" link="blue" vlink="purple">
<div class="WordSection1">
<p class="MsoNormal">I’ve used ESMF quite a lot during my post doc as part of NCL. It’s a very good regridding tool; simple to use with lots of functionality.<o:p></o:p></p>
<p class="MsoNormal">Generating the weights, if you need to use this method, take a little time to create and then you simply apply them like a cookie cutter.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Hope this helps.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal"><b><span style="font-size:12.0pt;color:black">From: </span></b><span style="font-size:12.0pt;color:black">gdal-dev <gdal-dev-bounces@lists.osgeo.org> on behalf of Chang Liao <changliao.climate@gmail.com><br>
<b>Date: </b>Sunday, August 23, 2020 at 1:08 AM<br>
<b>To: </b>Stephen Woodbridge <stephenwoodbridge37@gmail.com><br>
<b>Cc: </b>"gdal-dev@lists.osgeo.org" <gdal-dev@lists.osgeo.org>, "Rahkonen Jukka (MML)" <jukka.rahkonen@maanmittauslaitos.fi><br>
<b>Subject: </b>[EXTERNAL] Re: [gdal-dev] I have a problem getting higher resolution in a VRT file<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<div>
<p class="MsoNormal">Has anyone looked into the so called regrid in Earth system model? How is it different from GIS resampling?<o:p></o:p></p>
</div>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<h3 style="mso-margin-top-alt:0in;margin-right:0in;margin-bottom:12.0pt;margin-left:0in;vertical-align:baseline">
<span style="font-size:12.0pt;font-family:"Arial",sans-serif;color:#666666">Grid Remapping<o:p></o:p></span></h3>
<p style="margin:0in;vertical-align:baseline"><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#333333;border:none windowtext 1.0pt;padding:0in">ESMF has the option to build a standalone application, called </span><strong><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#333333"><a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__www.earthsystemcog.org_projects_regridweightgen&d=DwMFaQ&c=ApwzowJNAKKw3xye91w7BE1XMRKi2LN9kiMk5Csz9Zk&r=d9-Whdnf-TOkbqVja3ETyUOqHlFR1HbcWZvN0tb4JWU&m=gJ67R1rqmEZ1CNR6ZzSSdq0oVg69YSk0jOF6JHJUWqE&s=EFiJgIB5umvn8U9J6NTmmwOCMqomMKWHVJ2SfD2Frzw&e="><span style="font-size:14.5pt;color:#358C92;border:none windowtext 1.0pt;padding:0in;text-decoration:none">RegridWeightGen</span></a></span></strong><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#333333;border:none windowtext 1.0pt;padding:0in">,
that can generate interpolation weights in parallel. It's fast and can handle a wide variety of grids and grid options. It's not necessary to use the rest of ESMF to use it ... just provide grid files in a standard (netCDF-based) format.</span><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#333333"><o:p></o:p></span></p>
<div>
<p class="MsoNormal"><span style="font-family:"Arial",sans-serif"><a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__www.earthsystemcog.org_projects_esmf_&d=DwMFaQ&c=ApwzowJNAKKw3xye91w7BE1XMRKi2LN9kiMk5Csz9Zk&r=d9-Whdnf-TOkbqVja3ETyUOqHlFR1HbcWZvN0tb4JWU&m=gJ67R1rqmEZ1CNR6ZzSSdq0oVg69YSk0jOF6JHJUWqE&s=TV4fXf7pZBWLsEO2JXG9-NOHXJmBYltuaFB_ors565w&e=">https://www.earthsystemcog.org/projects/esmf/</a><o:p></o:p></span></p>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<p style="margin:0in;vertical-align:baseline"><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#333333;border:none windowtext 1.0pt;padding:0in">Thanks.</span><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#333333"><o:p></o:p></span></p>
<p style="margin:0in;vertical-align:baseline"><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#333333;border:none windowtext 1.0pt;padding:0in"><br>
<br>
</span><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#333333"><o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<div>
<p class="MsoNormal">On Thu, Aug 20, 2020 at 8:40 AM Stephen Woodbridge <<a href="mailto:stephenwoodbridge37@gmail.com">stephenwoodbridge37@gmail.com</a>> wrote:<o:p></o:p></p>
</div>
<blockquote style="border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in">
<p class="MsoNormal">Jukka,<br>
<br>
<br>
<br>
Thanks those are great threads and very educational.<br>
<br>
I solved my problem. I was using upsample="bilinear" rather than <br>
<br>
upsampling="bilinear" and fixing this gave the expected results. But if <br>
<br>
not for my stupid typo, I would not have had a chance to read those <br>
<br>
threads and google others regarding upsampling.<br>
<br>
<br>
<br>
Thanks for the assist,<br>
<br>
-Steve<br>
<br>
<br>
<br>
On 8/20/2020 10:13 AM, Rahkonen Jukka (MML) wrote:<br>
<br>
> Hi,<br>
<br>
><br>
<br>
> Resampling is science that would be nice to understand. Unfortunately I don't but I think that this thread is worth reading
<a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__osgeo-2Dorg.1560.x6.nabble.com_gdal-2Ddev-2Ddownsampling-2Dgeotiff-2Dwith-2Da-2Dlow-2Dpass-2Dfilter-2Dtd5385890.html&d=DwMFaQ&c=ApwzowJNAKKw3xye91w7BE1XMRKi2LN9kiMk5Csz9Zk&r=d9-Whdnf-TOkbqVja3ETyUOqHlFR1HbcWZvN0tb4JWU&m=gJ67R1rqmEZ1CNR6ZzSSdq0oVg69YSk0jOF6JHJUWqE&s=TXal_lZrArPU-zbwrfexbsf2Qvb2PdRg2gftiuDHXA0&e=" target="_blank">
osgeo-org.1560.x6.nabble.com/gdal-dev-downsampling-geotiff-with-a-low-pass-filter-td5385890.html</a>. In this gis.SE question cubic spline was considered good
<a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__gis.stackexchange.com_questions_30627_smoothing-2Dreinterpolating-2Draster-2Dwith-2Dgdal&d=DwMFaQ&c=ApwzowJNAKKw3xye91w7BE1XMRKi2LN9kiMk5Csz9Zk&r=d9-Whdnf-TOkbqVja3ETyUOqHlFR1HbcWZvN0tb4JWU&m=gJ67R1rqmEZ1CNR6ZzSSdq0oVg69YSk0jOF6JHJUWqE&s=KVyQa0XWkQle90WMihPdsRUOo7rGYd0bcO4iavrq0H4&e=" target="_blank">
https://gis.stackexchange.com/questions/30627/smoothing-reinterpolating-raster-with-gdal</a>.<br>
<br>
><br>
<br>
> -Jukka-<br>
<br>
><br>
<br>
> -----Alkuperäinen viesti-----<br>
<br>
> Lähettäjä: Stephen Woodbridge <<a href="mailto:stephenwoodbridge37@gmail.com" target="_blank">stephenwoodbridge37@gmail.com</a>><br>
<br>
> Lähetetty: torstai 20. elokuuta 2020 16.58<br>
<br>
> Vastaanottaja: Rahkonen Jukka (MML) <<a href="mailto:jukka.rahkonen@maanmittauslaitos.fi" target="_blank">jukka.rahkonen@maanmittauslaitos.fi</a>><br>
<br>
> Aihe: Re: [gdal-dev] I have a problem getting higher resolution in a VRT file<br>
<br>
><br>
<br>
> Hi Jukka,<br>
<br>
><br>
<br>
> Any thoughts on what would be a better way to upsample and image using GDAL?<br>
<br>
><br>
<br>
> I assumed, maybe incorrectly, that if I’m up sampling between two pixels with values of say 1 and 2 that a new pixel 50% between them would get a value of 1.5 and at 25% would get a value 1.25 etc. using linear interpolation and bilinear would also account
for rows above and below the current row.<br>
<br>
><br>
<br>
> Even, I specified resampling=“bilinear” in the vrt file is this ignored?<br>
<br>
><br>
<br>
> Thanks, Steve<br>
<br>
><br>
<br>
> Sent from my iPhone<br>
<br>
><br>
<br>
>> On Aug 20, 2020, at 8:23 AM, jratike80 <<a href="mailto:jukka.rahkonen@maanmittauslaitos.fi" target="_blank">jukka.rahkonen@maanmittauslaitos.fi</a>> wrote:<br>
<br>
>><br>
<br>
>> Even Rouault-2 wrote<br>
<br>
>>> ...<br>
<br>
>>> By default, VRT uses nearest resampling. You must specify something else.<br>
<br>
>>> Look for "A resampling attribute can be specified" in<br>
<br>
>>> <a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__gdal.org_drivers_raster_vrt.html&d=DwMFaQ&c=ApwzowJNAKKw3xye91w7BE1XMRKi2LN9kiMk5Csz9Zk&r=d9-Whdnf-TOkbqVja3ETyUOqHlFR1HbcWZvN0tb4JWU&m=gJ67R1rqmEZ1CNR6ZzSSdq0oVg69YSk0jOF6JHJUWqE&s=DF6beu2jDviD7F7np_eKCTpVWKapdeyv6tP9vMiUgMI&e=" target="_blank">
https://gdal.org/drivers/raster/vrt.html</a><br>
<br>
>>> ...<br>
<br>
>>><br>
<br>
>>> --<br>
<br>
>> Actually in the provided .vrt file I can see <SimpleSource<br>
<br>
>> resample="bilinear"><br>
<br>
>><br>
<br>
>> But isn't bilinear unsuitable for upsampling and some more blurring<br>
<br>
>> method might work better?<br>
<br>
>><br>
<br>
>> -Jukka Rahkonen-<br>
<br>
>><br>
<br>
>><br>
<br>
>><br>
<br>
>> --<br>
<br>
>> Sent from: <a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__osgeo-2Dorg.1560.x6.nabble.com_GDAL-2DDev-2Df3742093.html&d=DwMFaQ&c=ApwzowJNAKKw3xye91w7BE1XMRKi2LN9kiMk5Csz9Zk&r=d9-Whdnf-TOkbqVja3ETyUOqHlFR1HbcWZvN0tb4JWU&m=gJ67R1rqmEZ1CNR6ZzSSdq0oVg69YSk0jOF6JHJUWqE&s=d6jyxN2ZrEBQFC__T8Sj1oYs-UlIf_IsN4-GlqyWSMs&e=" target="_blank">
http://osgeo-org.1560.x6.nabble.com/GDAL-Dev-f3742093.html</a><br>
<br>
>> _______________________________________________<br>
<br>
>> gdal-dev mailing list<br>
<br>
>> <a href="mailto:gdal-dev@lists.osgeo.org" target="_blank">gdal-dev@lists.osgeo.org</a><br>
<br>
>> <a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__lists.osgeo.org_mailman_listinfo_gdal-2Ddev&d=DwMFaQ&c=ApwzowJNAKKw3xye91w7BE1XMRKi2LN9kiMk5Csz9Zk&r=d9-Whdnf-TOkbqVja3ETyUOqHlFR1HbcWZvN0tb4JWU&m=gJ67R1rqmEZ1CNR6ZzSSdq0oVg69YSk0jOF6JHJUWqE&s=HYO2u9pVjsgZZdTsYzwmPnQjySGNLExwnPch7xzADEk&e=" target="_blank">
https://lists.osgeo.org/mailman/listinfo/gdal-dev</a><br>
<br>
<br>
<br>
_______________________________________________<br>
<br>
gdal-dev mailing list<br>
<br>
<a href="mailto:gdal-dev@lists.osgeo.org" target="_blank">gdal-dev@lists.osgeo.org</a><br>
<br>
<a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__lists.osgeo.org_mailman_listinfo_gdal-2Ddev&d=DwMFaQ&c=ApwzowJNAKKw3xye91w7BE1XMRKi2LN9kiMk5Csz9Zk&r=d9-Whdnf-TOkbqVja3ETyUOqHlFR1HbcWZvN0tb4JWU&m=gJ67R1rqmEZ1CNR6ZzSSdq0oVg69YSk0jOF6JHJUWqE&s=HYO2u9pVjsgZZdTsYzwmPnQjySGNLExwnPch7xzADEk&e=" target="_blank">https://lists.osgeo.org/mailman/listinfo/gdal-dev</a><o:p></o:p></p>
</blockquote>
</div>
</div>
<p class="MsoNormal">-- <o:p></o:p></p>
<div>
<p class="MsoNormal" style="margin-bottom:12.0pt"><br>
Best Regards!<br>
<br>
Chang Liao,PhD<br>
Earth Scientist, Atmospheric Sciences & Global Change Division<br>
Pacific Northwest National Laboratory, WA, USA.<br>
Email: changliao.climate at <a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__gmail.com&d=DwMFaQ&c=ApwzowJNAKKw3xye91w7BE1XMRKi2LN9kiMk5Csz9Zk&r=d9-Whdnf-TOkbqVja3ETyUOqHlFR1HbcWZvN0tb4JWU&m=gJ67R1rqmEZ1CNR6ZzSSdq0oVg69YSk0jOF6JHJUWqE&s=Daly4H0zoTYR6l714C4-xmuxXmbBdgvgEB6Q2Q1APik&e=">
gmail.com</a> or chang.liao at <a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__pnnl.gov&d=DwMFaQ&c=ApwzowJNAKKw3xye91w7BE1XMRKi2LN9kiMk5Csz9Zk&r=d9-Whdnf-TOkbqVja3ETyUOqHlFR1HbcWZvN0tb4JWU&m=gJ67R1rqmEZ1CNR6ZzSSdq0oVg69YSk0jOF6JHJUWqE&s=hvD2SncYX8BOZU4_p_tfZbj7HT_EhtW0-L3gygXDwTo&e=">
pnnl.gov</a><br>
Personal Website: <a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__www.changliao.us&d=DwMFaQ&c=ApwzowJNAKKw3xye91w7BE1XMRKi2LN9kiMk5Csz9Zk&r=d9-Whdnf-TOkbqVja3ETyUOqHlFR1HbcWZvN0tb4JWU&m=gJ67R1rqmEZ1CNR6ZzSSdq0oVg69YSk0jOF6JHJUWqE&s=i6nmco-w6hzW_6TrSwilbgHHHAK7C87GyXJgBKQ9yDs&e=">http://www.changliao.us</a><br>
Skype: changliao1025<br>
Lab Website: <a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__www.pnnl.gov&d=DwMFaQ&c=ApwzowJNAKKw3xye91w7BE1XMRKi2LN9kiMk5Csz9Zk&r=d9-Whdnf-TOkbqVja3ETyUOqHlFR1HbcWZvN0tb4JWU&m=gJ67R1rqmEZ1CNR6ZzSSdq0oVg69YSk0jOF6JHJUWqE&s=wEUuOfig7XjI1-Uem_tPSB9ZeYcmwgkXjVEmyFqO2EI&e=">
www.pnnl.gov</a><o:p></o:p></p>
</div>
</div>
</body>
</html>