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>From: Darren Gallant <address@hidden> >Organization: UCAR/JOSS >Keywords: 200207111918.g6BJIGa29261 McIDAS AREA calibation Darren, >I'm trying to subsect an image, but imglist reveals something peculiar >about this image's ecor and lcor values: > >Pos Satellite/ Date Time Center Res (km) >Image_Size > sensor Lat Lon Lat Lon > --- ------------- ------------ -------- ---- ---- ----- ----- >------------ >9966 G-8 IMG 1 AUG 00214 20:15:00 31 86 > Band: 4 10.7 um Surface temp; longwave window 5.18 2.42 3245 x >8472 > proj: 0 created: 2002199 181713 memo: RT GVAR > type:GVAR cal type:RAW > offsets: data= 3328 navigation= 256 calibration= 2816 auxillary= >0 > doc length: 228 cal length: 0 lev length: 0 PREFIX= 232 > valcod: 214201500 zcor: 0 avg-smp: N > start yyddd: 2000214 start time:201515 start scan: 401 > lcor:-1639 ecor: -3363 bytes per pixel: 2 ss: 70 > Resolution Factors (base=1): Line= 4.0 Element= 4.0 >imglist.k: done > >I thought lcor and ecor were always positive. Are there positive >equivalents? No. The image in an AREA file can be offset so that the upper left point of the AREA refer to an image LIN,ELE that doesn exist. Think of taking an original image and then translating the values down and to the right in the AREA. The upper left portion of the image now refers to a LIN,ELE that is not in the new image: Original Image (1,1) +------------------------+ | | | ...... | | ........ | | .......... | | ............ | | .............. | | .............. | | ............ | | .......... | | ........ | | ...... | | | | | +------------------------+ Translated down and to left Image (-5,-5) +------------------------+ | | | | | | | | | + | | | | ...... | | ........ | | .......... | | ............ | | ..............| | ..............| | ............ | +------------------------+ Tom >From address@hidden Wed Jul 24 12:28:57 2002 >Subject: Re: 20020723: SSEC, CSU 4 km visible calibration (cont.) Thanks, Your explanation makes sense. So if I wanted to copy the image, I would use "LINELE=1 1 I PLACE=ULEFT" in my IMGCOPY? Darren >From address@hidden Wed Jul 24 12:35:21 2002 >Subject: Re: 20020723: SSEC, CSU 4 km visible calibration (cont.) Unidata Support, Actually using "LATLON=31 86 PLACE=CENTER" works much better. Thanks Darren Darren R. Gallant UCAR/JOSS Programmer/Technician Joint OfFice Of Science Support 303-497-2634 P.O. Box 3000 address@hidden Boulder,CO 80307-30000