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19990323: ARAOPT function arguments (cont.

Tom,

I beginning to see about ARAOPT function. Its slick, you know for
a program written in fortran mcidas has some slick stuff.

Ok, let me follow the previous line of conversation.

I have two GVAR GOES-10 files from channel 4 and 5. In the header
it says GVAR, RAW, with a 2 bytes per data word.

I would like to convert this 2 byte data to 4 byte integers. Also,
each integer I would like to represent temperature. 

Summary: 1) convert 2 byte words to 4 byte integers
         2) each 4 byte representing temperature.

Lastly, I want to subtract channel 4 -5, and store the data as two byte
data containing scaled temperature differences:
 
        3) write data as 2 byte representing temperature difference.


I assume i need to use araopt as follows:

call araopt(area4,1,'SPAC',4)           !  input channel 4 area
call araopt(area4,1,'UNIT',LIT('TEMP')) !  calibration to temperature

call araopt(area5,1,'SPAC',5)
call araopt(area5,1,'UNIT',LIT('TEMP')) !  channel 6

call araopt(area6,1,'SPAC',2)
call araopt(area6,1,'UNIT',LIT('TEMP))  !  output channel 6



Does that look correct?


What I have been doing though, I have been trying to practice
what I want to do by creating an exact duplicate of my AREA4 file
in AREA6.

I have used the following code:


      call araopt(area4no,1,'SPAC',2)
      call araopt(area5no,1,'SPAC',2)
      call araopt(area6no,1,'PREC',2)
      call araopt(area4no,1,'UNIT',LIT('TEMP'))
      call araopt(area5no,1,'UNIT',LIT('TEMP'))

c.... Read each line of data from the area files

      do line=1,nlines
         call redara(area4no,line-1,0,nelems,4,line4)
         call redara(area5no,line-1,0,nelems,5,line5)
         do elem=1,nelems
            line6(elem-1) = line4(elem-1)
         end do

c.... Pack array

        call pack(nelems,line6,line6)
c        call mpixel(nelems,2,2,line6)

c.... write line to destination area
         call wrtara(area6no,line-1,line6)
      end do


---------------------------------------

Question 2:
The following code does not work. The data is different
between my area file AREA004 and AREA006, although I think the
should be the same.

Question 2: Any suggestions of what I'm doing wrong?

Question 3: Do I need to pack the data (using PACK) or should
            I use MPIXEL (see code above)?



Thankyou for any help you may give.

Sincerely,
Craig Motell

>From address@hidden  Fri Mar 26 02:57:07 1999

Don't need to answer the previous question. Unless you already did.

I made many small changes and now I have the program working.

Funny thing is I had to create my output product or area as

1) VISR  rather than GVAR
2) stored with the units BRIT


Therefore, I have a good product if I convert the data to scaled
8 bit data, using a simple linear scaling.

Next, I will try to get my data as 2 byte (GVAR and RAW) data.

-------------------


As always I appreciate your great support.

Sincerely,
Craig Motell

>From address@hidden  Mon Mar 29 13:41:40 1999

I was looking in the navigation source code when I saw reference to
DNGENNAV.

What I did was try to copy the calls from the
program "AXFORM.PGM". THIS PROGRAM DOES what I want.

I am trying to run the program "NV1SAE" but this routine keeps failing
me. So probably I haven't initialized the Navigation routines properly

The goal is to get the satellite zenith angle at each pixel. This
I can get from the program "ANGLES".

I have an area file and to do the navigation I have the following
general steps:


------------------------- file segment with much code removed ------------
      implicit none
c.... Define functions
      integer   LIT, NV1SAE, NVSET
      parameter (MXCDSZ = 5*128)
      integer   navarr(MXCDSZ)
c
      common/NAVCM/ navarr

c.... Check to see if program set up a valid navigation block

      status = NVSET('AREA',area4no)
      write(charbuf,'(a10,i3)')'status=',status
      call sdest(charbuf,status)
c.... THIS SEEMS TO WORK, STATUS=0

      call araopt(area4no,1,'SPAC',4)

c.... Read each line of data from the area files
c.... Convert area coordinates (line,elem) to image coordinates (imgline,
c.... imgelem) for navigation routines

      do line=1,nlines
         imgline = upleftline + (line-1)*lres           ! image line coord.
         do elem=1,nelems
            imgelem = upleftelem + (elem-1)*eres
            status = NV1SAE(imgline,imgelem,xflag,lat,lon,xdummy)
C THIS RETURNS A -1
------------------------------------------------------------------

Three points:

0) I cut out some stuff in the code above that I don't think applies
to my question. I am able to read/write data from area files.

1) I had to add the program SATPOS.FOR to my code, I could NOT find it
as a library when I linked my program.

2) According to the programmer's guide I should do something like

nvprep(1,snav(1)).


Questions: 1) Is there any obvious things I am missing in my program
segment?

2) Should I instead follow the Programmer's reference program using
   nvprep, etc

3) I was asking what a "slot" is not a "socket". Sorry,that was a
freudian slip.

Comment: I agree with your NBA predictions exactly.

Thankyou for your help,
Craig Motell

>From address@hidden  Thu Apr  1 12:57:12 1999

I could never get my navigation routine to run.

Right now I do have navigation, I have taken the code from AXFORM.PGM.

I guess I would rather have you NOT pursue the navigation question.
That way I can ask you a question about calibration later on instead.

Thankyou,
Sincerely
Craig Motell