{"id":45543,"date":"2022-04-01T21:15:35","date_gmt":"2022-04-01T21:15:35","guid":{"rendered":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/?p=45543"},"modified":"2022-04-01T21:17:03","modified_gmt":"2022-04-01T21:17:03","slug":"using-polar2grid-and-noaa-class-viirs-data-to-create-imagery","status":"publish","type":"post","link":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/archives\/45543","title":{"rendered":"Using Polar2Grid and NOAA CLASS VIIRS data to create imagery"},"content":{"rendered":"\n
\"\"<\/a>
NOAA-20 I05 (11.45 \u00b5m) imagery over the Arctic Ocean, 1455-1510 UTC on 1 February 2022 (Click to — greatly!! — enlarge)<\/figcaption><\/figure>\n\n\n\n

Previous blog posts (example<\/a>) have documented how to create imagery from the VIIRS instrument, and this one is another example. For example, if you receive a request for VIIRS imagery such as this one: “If you have time to try a case, you could pick Feb 1, 2022 near North Pole Point for 11 um channel” — how do you proceed? A first step is to determine the day\/time of the data, and that’s achieved by looking at orbits over the Arctic, at this website<\/a>. That website also has an archive<\/a>, and the archive for Arctic passes on 1 February 2022 is here<\/a>. The image<\/a> shows NOAA-20 passing over Greenland, the Arctic Ocean, and then moving over eastern Russia between 1455 and 1510 UTC on 1 February 2022. Now you know the times to request.<\/p>\n\n\n\n

NOAA CLASS<\/a> is the data repository that stores VIIRS imagery from NOAA-20 and Suomi-NPP. Go to the website, an log in (register if you have not already), and choose JPSS VIIRS SDRs (Operational Sensor Data Records) as shown below. Choosing those data and clicking >>GO to the right of the drop-down menu bar will move you to a new data-selection menu, where you will select the day\/time of the data (1 February 2022, 14:55 Start time, 15:10 end time), and the band (I chose SVI05 — the 11.45 \u00b5m Imager channel, with 375-m resolution, that is: VIIRS Imagery Band 05 SDR (SVI05) (public 02\/07\/2012)<\/strong> ), and the satellite (NOAA-20). Geolocation data must also be selected, and Polar2Grid will expect the GITCO<\/strong> files. Choose them ( VIIRS Image Bands SDR Ellipsoid Terrain Corrected Geolocation (GITCO) (public 02\/07\/2012)<\/strong>) as well. It is very important, however, that your User Preferences are configured so that the data are disaggregated! Click on User Preferences<\/a>, and make that selection. The User Preferences page should include information as shown here<\/a>.<\/p>\n\n\n\n

\"\"<\/a>
NOAA CLASS front page showing the VIIRS data to select (Click to enlarge)<\/figcaption><\/figure>\n\n\n\n

The steps above will produce 12 matches — 6 files of SVI05 and 6 GITCO files. Submit your order and wait for the email notification that the files are ready. While you are waiting, if you’ve not done so already, download the Polar2Grid software<\/a> from CIMSS CSPP<\/a> Site (CSPP: Community Satellite Processing Package; note that a free registration might be required). Expand the downloaded (compressed tar) file into an empty directory, and enter this unix command: export POLAR2GRID_HOME=\/directory\/where\/the\/expanded\/file\/sits.<\/p>\n\n\n\n

NOAA CLASS will send an email once the data are staged and ready for you. Download those data, and then enter this command:<\/p>\n\n\n\n

sh .\/polar2grid.sh viirs_sdr gtiff -p i05 -g polar_canada -f \/directory\/holding\/downloaded\/SVI05Data\/SVI05* \/directory\/holding\/downloaded\/GITCOdata\/GITCO*<\/code><\/p>\n\n\n\n

That code takes the viirs_sdr and GITCO data pointed to by the -f flag and creates a geotiff of i05 (11.45) imagery. Because these data are near the Pole, I’ve specified a grid (‘-g polar_canada’) to be used (a full list of pre-defined grids is here<\/a>, part of the Polar2Grid online documentation<\/a>). The command will stitch together the data in the 6 different files, and you’ll see an image at full resolution, as shown above. I also used software to add coastlines and lat\/lon (‘grid’) lines.<\/p>\n\n\n\n

sh .\/add_coastlines.sh --add-grid --grid-D 10 10 --grid-d 10 10 --add-coastlines noaa20_viirs_i05_20220201_145336_polar_canada.tif<\/code><\/p>\n","protected":false},"excerpt":{"rendered":"

Previous blog posts (example) have documented how to create imagery from the VIIRS instrument, and this one is another example. For example, if you receive a request for VIIRS imagery such as this one: “If you have time to try a case, you could pick Feb 1, 2022 near North Pole Point for 11 um […]<\/p>\n","protected":false},"author":19,"featured_media":45547,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[37,78,109,48],"tags":[],"class_list":["post-45543","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-arctic","category-noaa-20","category-software","category-viirs"],"acf":[],"_links":{"self":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/45543","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/users\/19"}],"replies":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/comments?post=45543"}],"version-history":[{"count":5,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/45543\/revisions"}],"predecessor-version":[{"id":45552,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/45543\/revisions\/45552"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media\/45547"}],"wp:attachment":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media?parent=45543"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/categories?post=45543"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/tags?post=45543"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}