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>From: Edward Hindman <address@hidden> >Organization: CCNY >Keywords: 200104271758.f3RHwBL11872 McIDAS Ward, re: non-Mollweide global composite >The AREA8760 image looks like a remapped Mollweide with no higher >spatial resolution. Actually, the Mollweide IR image in the Unidata-Wisconsin datastream is created from this image, and the image is twice the resolution of the UW stream Mollweide IR. The following lists should illustrate the point. MYDATA/IMAGES.8760 is the image from the SSEC FTP site. Its computed resolution at the image's center is 33 km: IMGLIST MYDATA/IMAGES.8760 FORM=EXP Image file directory listing for:MYDATA/IMAGES Pos Satellite/ Date Time Center Res (km) Image_Size sensor Lat Lon Lat Lon --- ------------- ------------ -------- ---- ---- ----- ----- ------------ 8760 G-8 IMG 30 APR 01120 21:00:00 0 0 Band: 4 10.7 um Surface temp; longwave window 1.0 1.0 600 x 1200 proj: 0 created: 2001120 212743 memo: type:PRD cal type:BRIT offsets: data= 1280 navigation= 256 calibration= 768 auxillary= 0 doc length: 0 cal length: 0 lev length: 0 PREFIX= 0 valcod: 0 zcor: 1 avg-smp: N lcor: 1 ecor: 1 bytes per pixel: 1 ss: 70 Image Center Point Res (derived) Lat: 33.36 (km) Lon: 33.36 (km) IMGLIST: done This is a listing of the latest Mollweide-IR image from the Unidata-Wisconsin datastream. Its computed resolution at the image's center is 52 km in the horizontal and 64 km in the vertical: IMGLIST RTIMAGES/MOLL-IR FORM=EXP Image file directory listing for:RTIMAGES/MOLL-IR Pos Satellite/ Date Time Center Res (km) Image_Size sensor Lat Lon Lat Lon --- ------------- ------------ -------- ---- ---- ----- ----- ------------ 2 G-8 IMG 30 APR 01120 18:00:00 0 -1 Band: 4 10.7 um Surface temp; longwave window 1.0 1.0 350 x 640 proj: 0 created: 2001120 193023 memo: type:VISR cal type:BRIT offsets: data= 768 navigation= 256 calibration= 0 auxillary= 0 doc length: 0 cal length: 0 lev length: 0 PREFIX= 0 valcod: 0 zcor: 1 avg-smp: N lcor: 9826 ecor: 9681 bytes per pixel: 1 ss: 70 Image Center Point Res (derived) Lat: 52.16 (km) Lon: 64.34 (km) IMGLIST: done >It's terribly pixilated over Nepal. Admitedly, neither image has the kind of resolution that either of us would want, but the rectilinear one is better than the Mollweide remapped one. I just displayed both of these at equal display resolutions and compared them over Nepal. It looks to me that the rectilinear image is much less pixelated than the Mollweide one. Try this yourself: IMGDISP MYDATA/IMAGES.8760 1 LATLON=30 -92 EU=IMAGE SF=YES REFRESH='EG;MAP SAT;MAP X 5 FILE=OUTLHPOL' IMGDISP RTIMAGES/MOLL-IR 2 LATLON=30 -92 EU=IMAGE SF=YES REFRESH='EG;MAP SAT;MAP X 5 FILE=OUTLHPOL' MAG=2 It may be possible that you are comparing a Mollweide remap of the rectilinear image with a Mollweide remap of the Mollweide image. After doing that, I have to admit that the remapped Mollweide image looks better. I would not, however, compare the products of the two remaps, but rather the remap of the Mollweide with the blow-up load of the rectilinear one. Here is what I did, so you can see what I am trying to point out: 1) rectilinear image remapped to Mollweide specifying output resolution of 8 IMGREMAP MYDATA/IMAGES.8760 MYDATA/IMAGES.1235 LATLON=30 -92 PRO=MOLL RES=8 IMGDISP MYDATA/IMAGES.1235 1 LATLON=30 -92 EU=IMAGE SF=YES REFRESH='EG;MAP SAT 1;MAP X 5 FILE=OUTLHPOL' 2) Unidata-Wisconsin Mollweide IR remapped to Mollweide specifying output resolution of 8 IMGREMAP RTIMAGES/MOLL-IR MYDATA/IMAGES.1236 LATLON=30 -92 PRO=MOLL RES=8 IMGDISP MYDATA/IMAGES.1236 2 LATLON=30 -92 EU=IMAGE SF=YES REFRESH='EG;MAP SAT 1;MAP X 5 FILE=OUTLHPOL' 3) display the rectilinear image at approx. the same resolution on frame 3 IMGDISP MYDATA/IMAGES.8760 3 LATLON=30 -92 MAG=2 EU=IMAGE SF=YES REFRESH='EG;MAP H;MAP X 5 FILE=OUTLHPOL' 4) make a loop of all three displays so they can be compared visually LB 1 3 DR 3*20 TERM L ON >The IMGREMAP >instructions you gave us on 27 April produced as good an image from the >standard Mollweide. Please remember that when you remap images, you change data values. The remap might end up looking less pixelated, but this is a smoothing effect that occurs in the remap. >Where is the higher-resolution Mollweide imagery? AREA8760 is the higher resolution image that I was referring to. It has twice the resolution as the one in the Unidata-Wisconsin datastream. >It's criminal that India does not make Insat data available real-time or >otherwise. I believe that this has changed. The Indians at least talked about making Insat imagery freely available in a non-encrypted form about 9 months to a year ago. I guess that they figured that since China's FY-2 would be imaging more-or-less the same area and making the data available, it was a losing battle to keep the images encrypted. What I have been trying to find for you is a site that has GMS data that is willing to give you ADDE access. I'll keep looking... Tom