/************************************************************************
                 INSTRUCTIONS FOR READING MEAN PARAMETER DATA
                    ON A LATITUDE-LONGITUDE GRID

                           Ocean Climate Laboratory
                     National Oceanographic Data Center

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           FORMAT FOR READING DATA

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 Program will print a five grid square box based of user specified longitude,
 latitude, and depth.  The latitude and longitude entered will be the center
 grid point in the box.  This program works for one-degree and
 five-degree data

 Constant descriptions
        idim=longitude
        jdim=latitude
        kdim=standard depth levels

 33 Standard level depths (in meters):
 0,10,20,30,50,75,100,125,150,200,250,300,400,500,600,700,800,900,1000,
 1100,1200,1300,1400,1500,1750,2000,2500,3000,3500,4000,4500,5000,5500

 Annual and seasonal analyzed fields contain 33 levels (0-5500 m)
 Monthly analyzed fields contain 24 levels (0-1500 m)

 Units: degrees celsius for temperature
        practical salinity scale for salinity
        milliliters/liter for oxygen
        micro mole per liter for nutrients
 temperature is in situ temperature
 Land value= -99.9999 for f8.4 read files
           = -100. for f8.0 read files

*****************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define idim0 360
#define jdim0 180

float dat[idim0 * jdim0];

main()

{

 FILE *fp;
 char filename[80];
 int i0, i, j, k, ispace, idim, jdim;
 int lon,lat,ifield,itype,kx;
 int jstart,jend,istart,iend;
 float rlon,rlat,space;

/*************************************************

 OPEN FILE

**************************************************/

 puts(" Enter file name\0");
 gets(filename);

 printf(" %s\n",filename);
 if ((fp = fopen(filename,"rb+\0")) == NULL)
  printf("UNABLE TO OPEN FILE\n");

 else {

/*************************************************

 GET NECESSARY INFORMATION

**************************************************/

  printf("Enter file type:\n");
  printf("  0: analyzed field (an)\n");
  printf("  1: points within radius of influence field (gp)\n");
  printf("  2: data distribution (dd)\n");
  printf("  3: raw (unanalyzed) mean fields (mn)\n");
  printf("  4: standard deviation field (sd)\n");
  printf("  5: standard error of the mean field (se)\n");
  printf("  6: minus annual field (ma)\n");
  printf("  7: observed minus annual field (oa)\n");
  printf("  8: basin mask or landsea mask (*.msk)\n> ");
  scanf("%d",&ifield);

/***************************************************

   Fields 2, 3, 4 & 5 may be five degree files
   Fields 1,2 & 8 values are stored as f8.0, land=-100. (if applicable)
   Fields 0,3,4,5,6, & 7 are stored as f8.4, land=-99.9999

*****************************************************/

  if ( ifield >= 2 && ifield <= 5 ) {
   printf("Enter (1) for one-degree grid, (5) for five-degree grid\n>");
   scanf("%d",&ispace);
  }

  else ispace=1;

  if ( ispace == 5 ) {
   idim=idim0/5;
   jdim=jdim0/5;
   space=5.;
  }

  else {
   idim=idim0;
   jdim=jdim0;
   space=1.;
  }

  if ( ifield == 1 || ifield == 2 || ifield == 8 ) itype=0;
  else itype=1;

  printf("\nDepth Level (1-33) ?\n> ");
  scanf("%d",&kx);

/*************************************************

 READ IN DATA

**************************************************/

  for ( k = 1; k <= kx; k++ ) {

   for ( j = 0; j < jdim; j++ ) {

    for ( i = 0; i < idim; i++ ) 

     fscanf( fp, "%f", ( dat + ( j * idim ) + i ) );

   }

  }

/**************************************************

 PROMPT FOR WHICH AREA TO WRITE TO SCREEN 

**************************************************/

  printf("\n Enter latitude center for area to print (-90 to 90)\n> ");
  scanf("%f",&rlat); 

  printf("\n Enter longitude center for area to print (-180 to 180)\n> ");
  scanf("%f",&rlon); 

  lat=((rlat+90.)/(space+1.E-7))+1;

  if (rlon <= 0 ) lon=((rlon+360.)/(space+1.E-7))+1;
  else lon=(rlon/(space+1.E-7))+1;

  printf("\n lon-lat point (%.1f,%.1f) = grid point (%d,%d)\n",
          rlon,rlat,lon,lat);

/**************************************************

 DISPLAY AREA

**************************************************/

  istart= lon -4;
  iend= lon+5;

  jstart= lat-4;
  jend=lat+5;

  printf("\n         Values for depth level %d\n\n ",kx);

  printf("GRID   ");

  for ( i0 = istart; i0 <= iend; i0++ ) {
 
   if ( i0 > 0 && i0 <= idim ) i = i0;
   else if ( i0 <= 0 ) i= i0+idim;
   else i= i0-idim;
   printf("    %3d",i);

  }

  printf("\n ");
  if ( istart <= 0 ) istart= istart+idim;
  if ( iend > idim ) iend=iend-idim;

  for ( j = jend-1; j >= jstart-1; j-- ) {

   printf("\n  %3d   ",j+1);

   if ( iend > istart ) { 
    for ( i = istart-1; i < iend; i++ ) 
     printf("%7.2f",*(dat+ (j*idim) + i) );
   } 

   else {
    for ( i = istart-1; i < idim; i++ ) 
     printf("%7.2f",*(dat+ (j*idim) + i) );
    for ( i = 0; i < iend; i++ ) 
     printf("%7.2f",*(dat+ (j*idim) + i) );
   }

  }

  printf("\n \n ");

 }

}