>From: "Jason J. Levit" <address@hidden> >Organization: Center for Analysis and Prediction of Storms, University of Okla homa >Keywords: 200110222135.f9MLZn102781 McIDAS-X ADDE GINI AREA Jason, >Yesterday, in my discussions with Kevin, he mentioned that there is a >way to re-map the converted GINI data in TANC format into a image with >the GVAR projection (however, as you mentioned, this is the second >remapping of the data). Yes. McIDAS has a command, IMGREMAP, that allows one to remap into several projections as well as into a file that has its own projection (like GVAR). >However, the data we receive via the Storm >Prediction Center has as it's map projection "GVAR". So, this data is probably not remapped. >So, I'm wondering >if the McIDAS data we're receiving is already re-mapped a second time? The "McIDAS" data you are receiving? Do you mean the NOAAPORT GINI data (which is not in McIDAS format), or are you referring to the imagery that is included in the Unidata-Wisconsin datastream (which all Unidata participants are entitled to get)? >I'm looking into this now via e-mails. > > When I use IMGLIST to look at the formats of the data, here's what I >notice: > >#1) Data we receive from the Storm Prediction Center: > Pos Satellite/ Date Time Center Res (km) >Image_Size > sensor Lat Lon Lat Lon > --- ------------- ------------ -------- ---- ---- ----- ----- >------------ > 1 G-8 IMG 25 OCT 01298 17:02:00 36 96 > Band: 1 0.65 um Visible - Cloud Cover 1.0 2.0 2800 >x 4200 > proj: 0 created: 2001298 171330 memo: RT GVAR > type:VISR cal type:BRIT > offsets: data= 2816 navigation= 256 calibration= 0 >auxillary= 0 > doc length: 0 cal length: 0 lev length: 0 PREFIX= 0 > valcod: 0 zcor: 0 avg-smp: N > start yyddd: 2001298 start time:170142 start scan: 372 > lcor: 3060 ecor: 8061 bytes per pixel: 1 ss: 70 > Image Center Point Res (derived) Lat: 1.47 (km) Lon: 1.33 >(km) OK. We can see that this data is already converted from RAW to VISR (2-byte to 1-byte). >#2) Converted GINI data (from GINI to VISR/BRIT): > Pos Satellite/ Date Time Center Res (km) >Image_Size > sensor Lat Lon Lat Lon > --- ------------- ------------ -------- ---- ---- ----- ----- >------------ > 1 G-8 IMG 25 OCT 01298 16:45:00 41 88 > Band: 1 0.65 um Visible - Cloud Cover 1.0 1.0 5120 >x 5120 > proj: 0 created: 2001298 194011 memo: GINI:: Sat 11 SecID 1 >ChID 1 > 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: 0 avg-smp: N > start yyddd: 2001298 start time:164500 start scan: 0 > lcor: 1 ecor: 1 bytes per pixel: 1 ss: 70 > Image Center Point Res (derived) Lat: 0.98 (km) Lon: 0.98 >(km) Instead of saying "Converted GINI", I would say GINI since all NOAAPORT GINI data has been remapped into projections that match grid projections in the NOAAPORT datastream. This was done by the NWS so that AWIPS workstations could overlay satellite images without having to do any navigation transforms (so the displays are fast). >The resolution of the two images is different, yet they are both >VISR/BRIT data from GOES-08. They are both VISR (meaning data values range from 0 to 255) and they are both originally from GOES, yes. >I'm guessing the first data has been remapped a second time? No, I would not say that. I would say that the first image has been created from a GVAR RAW image by: o blowing down in the element dimension (original GVAR images are over sampled in the element dimension by a factor of 1.7) o turning RAW counts into BRIT values by scaling the 10 bit data to 8 bits Neither of these conversions reflects a remapping. >Maybe I should try the remapping and see if this creates a similar data >set. How would I use IMGREMAP to try this? Again, thanks for your >help. Here is a way to remap the GINI data into the GOES projection of the Storm Prediction Center images you have. 1) make a copy of a GOES image that is appropriate to the GINI image that you are going to want to remap (i.e., a GOES-8 image for the GOES-8 GINI image and a GOES-10 image for the GOES-10 GINI image): Since I don't know the dataset name you use for images you get from the Storm Prediction Center, I will use 'STORM/GOES08VIS' for GOES-8 VIS images. I will also assume that you have defined the MYDATA/IMAGES dataset (if you havn't, simply run 'BATCH MYDATA.BAT' from your McIDAS session): IMGCOPY STORM/GOES08VIS MYDATA/IMAGES.2000 SIZE=ALL 2) remap your latest GINI GOES-8 VIS image into this copy: IMGREMAP GINICAPS/GOES08VIS MYDATA/IMAGES.2000 3) since IMGREMAP does not transfer several pieces of information from the original image to the remapped one, you will have to use IMGLIST on the original to discern the information and IMGCHA on the remapped one to change those values: IMGLIST STORM/GOES08VIS FORM=EXP Now change the DAY, TIME, and BAND in the remapped image: IMGCHA MYDATA/IMAGES.2000 BAND=<band#> DAY=<day> TIME=<time> Here <band#> is the band number you got from the IMGLIST; <day> is the DAY you got from the IMGLIST, and <time> is the TIME you got from the IMGLIST. After doing the above, the image in MYDATA/IMAGES.2000 will be the remapped copy of the original GINICAPS/GOES08VIS image. You can further refine the IMGCOPY and IMGREMAP commands above to do things like copy a particular image (specify DAY= and TIME= keywords to specify which image to copy/remap). Please let me know if the above is not clear enough. Tom
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