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[McIDAS #FBA-307750]: PATH command



Hi Kwan,

I have been looking at the MSG data you sent on Sunday.  Not being up to speed
on using the segmented MSG data files, I had to spend some time looking through
the code to see what was happening.  Here is what I found:

I created the an ADDE dataset with group name MSG as follows:

<as 'mcidas', but could be any user>

-- copy the files you sent to a directory, I chose /home/mcidas/tmp

DSSERVE ADD MSG/VISIR MSGT TYPE=IMAGE 
DIRFILE=/home/mcidas/tmp/H-000-MSG1__-MSG1 * "MSG segmented images
Adding the group MSG as a local dataset
Group/Descriptor         Type  Format & Range     RT Comment
------------------------ ----- ------------------ -- --------------------
MSG/VISIR                IMAGE MSGT                  METEOSAT SEGMENTED IMAGES
                               DIRFILE=/home/mcidas/tmp/H-000-MSG1__-MSG1*
DSSERVE: done
 
IMGLIST MSG/VISIR
Image file directory listing for:MSG/VISIR
 Pos Satellite/         Date       Time      Center   Band(s)
     sensor                                 Lat  Lon
 --- -------------  ------------  --------  ---- ---- ------------
   2  METEOSAT8     18 JUL 06199  11:00:00     0    0 1-11
IMGLIST: done

IMGLIST MSG/VISIR FORM=ALL
Image file directory listing for:MSG/VISIR
 Pos Satellite/         Date       Time      Center      Res (km)   Image_Size
     sensor                                 Lat  Lon    Lat   Lon
 --- -------------  ------------  --------  ---- ----  ----- ----- ------------
   1  METEOSAT8     18 JUL 06199  11:00:00     0    0
   Band: 1    0.6 um VIS Cloud and Surface Features     3.02  3.00  3712 x 3712
   Band: 2    0.8 um VIS Aerosols over Water, Veg       3.02  3.00  3712 x 3712
   Band: 3    1.6 um Near IR - Surface, cloud phase     3.02  3.00  3712 x 3712
   Band: 4    3.9 um IR Low Cloud/Fog,Fire Detection    3.02  3.00  3712 x 3712
   Band: 5    6.2 um IR Upper-level Water Vapor         3.02  3.00  3712 x 3712
   Band: 6    7.3 um IR Mid-level Water Vapor           3.02  3.00  3712 x 3712
   Band: 7    8.7 um IR Total Water,Cloud Phase,Dust    3.02  3.00  3712 x 3712
   Band: 8    9.7 um Ozone                              3.02  3.00  3712 x 3712
   Band: 9    10.8 um IR Surface/Cloud-top Temp         3.02  3.00  3712 x 3712
   Band: 10   12.0 um IR SFC/Cloud Temp, Low-level WV   3.02  3.00  3712 x 3712
   Band: 11   13.4 um IR CO2, Cloud Heights             3.02  3.00  3712 x 3712
     proj:    0 created: 2006199 110000  memo: MSG data from XRIT
     type:MSG      cal type:RAW
     offsets:  data=    2020 navigation=  256 calibration=  768 auxiliary=    0
     doc length:   0   cal length:   0   lev length:   0 PREFIX=   0
     valcod:          0 zcor:  1 avg-smp: N
     start yyddd: 2006199  start time:110000  start scan:    0
     lcor:    1  ecor:     1  bytes per pixel: 2  ss: 51
     Resolution Factors (base=1):   Line=    3.0   Element=    3.0
IMGLIST: done


Up to this point, I believe that I have done exactly what you did.  Next,
I tried displaying the image:

IMGDISP MSG/VISIR LAT=0 0 EU=IMAGE BAND=9
Beginning Image Data transfer, bytes= 686020
IMGDISP: loaded frame  17
IMGDISP: done
EU: Restoring IMAGE.ET to frame(s)= 17
EU: Done

All looks like it should be OK, but it isn't since no image data is displayed.


By turning on server tracing when doing an image load, one can see debugging
information from the server (if the dataset is local).  From this debugging
information, I learned that the server was not finding a file it was looking 
for.
I modified the server code, ~mcidas/mcidas2006/src/msgtaget.for, to list
out the file it was looking for.  I found that it was looking for a segment file
that you do not have, the one covering the load point, LATLON=0 0.  The
segment file you have, turns out to be #2 in a sequence of some number greater 
than
2.  I started guessing Lat,Lons that would be covered until I was able to
display the image.  The following worked:

IMGDISP MSG/VISIR LAT=-30 0 EU=IMAGE BAND=9 MAG=-4 REFRESH='EG;MAP SAT'
Beginning Image Data transfer, bytes= 528520
IMGDISP: loaded frame  17
EG;MAP SAT
IMGDISP: done
EU: Restoring IMAGE.ET to frame(s)= 17
EU: Done
Erased graphic frame(s) 17-17
MAP: Completed frame 17

After getting values displayed in the image frame, I was able to determine
that the segment you provided in:

H-000-MSG1__-MSG1________-IR_108___-000002___-200607181100-__

covers the latitudes of approximately 24:41S to 44:01S.

Try loading an image using a centerpoint of -34, 0:

IMGDISP MSG/VISIR LAT=-34 0 EU=IMAGE BAND=9 MAG=-4 REFRESH='EG;MAP SAT'

and see if you get a valid display like I did.

So, it appears that you are missing several of the segments needed for
a complete display.  Given that your PATH plots were over Europe, I
would imagine that you would be needing segments greater than or equal
to 5 or so.  For reference, the segment number is listed in the file
name:

H-000-MSG1__-MSG1________-IR_108___-000002___-200607181100-__
                                         ^ segment number

After you get all of the segments for the image, you should then be
able to use IMGDISP for any point on the disk, and IMGCOPY to write
the image into a McIDAS AREA if you want.  For instance, after you
get all of the segments and put them in the same directory as the
other H-000* files, you should be able to do:

IMGCOPY MSG/VISIR MYDATA/IMAGES.3000 SIZE=ALL

Please let me know if you are able to replicate my findings above.

Cheers,

Tom
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Ticket Details
===================
Ticket ID: FBA-307750
Department: Support McIDAS
Priority: Normal
Status: Closed


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