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. 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.
Hope this helps. From: gdal-dev <[email protected]> on behalf of Chang Liao <[email protected]> Date: Sunday, August 23, 2020 at 1:08 AM To: Stephen Woodbridge <[email protected]> Cc: "[email protected]" <[email protected]>, "Rahkonen Jukka (MML)" <[email protected]> Subject: [EXTERNAL] Re: [gdal-dev] I have a problem getting higher resolution in a VRT file Has anyone looked into the so called regrid in Earth system model? How is it different from GIS resampling? Grid Remapping ESMF has the option to build a standalone application, called RegridWeightGen<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=>, 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. https://www.earthsystemcog.org/projects/esmf/<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=> Thanks. On Thu, Aug 20, 2020 at 8:40 AM Stephen Woodbridge <[email protected]<mailto:[email protected]>> wrote: Jukka, Thanks those are great threads and very educational. I solved my problem. I was using upsample="bilinear" rather than upsampling="bilinear" and fixing this gave the expected results. But if not for my stupid typo, I would not have had a chance to read those threads and google others regarding upsampling. Thanks for the assist, -Steve On 8/20/2020 10:13 AM, Rahkonen Jukka (MML) wrote: > Hi, > > Resampling is science that would be nice to understand. Unfortunately I don't > but I think that this thread is worth reading > osgeo-org.1560.x6.nabble.com/gdal-dev-downsampling-geotiff-with-a-low-pass-filter-td5385890.html<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=>. > In this gis.SE question cubic spline was considered good > https://gis.stackexchange.com/questions/30627/smoothing-reinterpolating-raster-with-gdal<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=>. > > -Jukka- > > -----Alkuperäinen viesti----- > Lähettäjä: Stephen Woodbridge > <[email protected]<mailto:[email protected]>> > Lähetetty: torstai 20. elokuuta 2020 16.58 > Vastaanottaja: Rahkonen Jukka (MML) > <[email protected]<mailto:[email protected]>> > Aihe: Re: [gdal-dev] I have a problem getting higher resolution in a VRT file > > Hi Jukka, > > Any thoughts on what would be a better way to upsample and image using GDAL? > > 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. > > Even, I specified resampling=“bilinear” in the vrt file is this ignored? > > Thanks, Steve > > Sent from my iPhone > >> On Aug 20, 2020, at 8:23 AM, jratike80 >> <[email protected]<mailto:[email protected]>> >> wrote: >> >> Even Rouault-2 wrote >>> ... >>> By default, VRT uses nearest resampling. You must specify something else. >>> Look for "A resampling attribute can be specified" in >>> https://gdal.org/drivers/raster/vrt.html<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=> >>> ... >>> >>> -- >> Actually in the provided .vrt file I can see <SimpleSource >> resample="bilinear"> >> >> But isn't bilinear unsuitable for upsampling and some more blurring >> method might work better? >> >> -Jukka Rahkonen- >> >> >> >> -- >> Sent from: >> http://osgeo-org.1560.x6.nabble.com/GDAL-Dev-f3742093.html<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=> >> _______________________________________________ >> gdal-dev mailing list >> [email protected]<mailto:[email protected]> >> https://lists.osgeo.org/mailman/listinfo/gdal-dev<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=> _______________________________________________ gdal-dev mailing list [email protected]<mailto:[email protected]> https://lists.osgeo.org/mailman/listinfo/gdal-dev<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=> -- Best Regards! Chang Liao,PhD Earth Scientist, Atmospheric Sciences & Global Change Division Pacific Northwest National Laboratory, WA, USA. Email: changliao.climate at gmail.com<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=> or chang.liao at pnnl.gov<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=> Personal Website: http://www.changliao.us<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=> Skype: changliao1025 Lab Website: www.pnnl.gov<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=>
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