get_coord.c

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#include "prototypes.h"
 
void get_coord(double maximum_latitude,double minimum_latitude,double center_longitude)
 
{
 
 int i,k,maxi,maxj;
 struct HRAP hrap;
 struct HRAP irap;
 float cx,cy;
 extern struct h_grid *h_grid; 
 extern struct top *topo;
 int mini,minj,ix,iy,elevation,kk,jj;
 float lat,lon,distance,value,dist1,dist2,dist;
 
 h_grid=(struct h_grid *) calloc(1,sizeof(struct h_grid));
 if(h_grid==NULL) {
 
                   printf("could not allocate h_grid space\n");
                   exit(1);
 
                  }  
 
 maxi=-1;maxj=-1;mini=999999;minj=99999;
 
 hrap=LatLongToHrap((float)maximum_latitude,(float)center_longitude-6.0);
 
 cx=(int)hrap.x+1;
 cy=(int)hrap.y;
 
 if(cx > maxi)
           maxi=cx;
 
 if(cy > maxj)
           maxj=cy;
 
 if(cx < mini)
           mini=cx;
 
 if(cy < minj)
           minj=cy;
 
 hrap=LatLongToHrap((float)maximum_latitude,(float)center_longitude+6.0);
 
 cx=(int)hrap.x+1;
 cy=(int)hrap.y;
 
 if(cx > maxi)
           maxi=cx;
 
 if(cy > maxj)
           maxj=cy;
 
 if(cx < mini)
           mini=cx;
 
 if(cy < minj)
           minj=cy;
 
 hrap=LatLongToHrap((float)minimum_latitude,(float)center_longitude-6.0);        
 
 cx=(int)hrap.x+1;
 cy=(int)hrap.y;
 
 if(cx > maxi)
           maxi=cx;
 
 if(cy > maxj)
           maxj=cy;
 
 if(cx < mini)
           mini=cx;
 
 if(cy < minj)
           minj=cy;
 
 hrap=LatLongToHrap((float)minimum_latitude,(float)center_longitude+6.0);
 
 cx=(int)hrap.x+1;
 cy=(int)hrap.y;
 
 if(cx > maxi)
           maxi=cx;
 
 if(cy > maxj)
           maxj=cy;
 
 if(cx < mini)
           mini=cx;
 
 if(cy < minj)
           minj=cy;
 
/*allocate necessary space */
 
h_grid->maxi=maxi-mini;
h_grid->maxj=maxj-minj;
 
maxi=h_grid->maxi;
maxj=h_grid->maxj;
 
h_grid->box=(struct coord **) calloc(maxi,sizeof(struct coord *));
h_grid->elev=(short int**) calloc(maxi,sizeof(short int *));
h_grid->latlon=(struct HRAP **) calloc(maxi,sizeof(struct HRAP *));
 
if(h_grid->box==NULL ||  h_grid->elev==NULL || h_grid->latlon==NULL) {
 
                            printf("no memory for hrap array\n");
                            exit(1);
 
              }
 
for(i=0;i<maxi;i++) {
 
      h_grid->box[i]=(struct coord *) calloc(maxj,sizeof(struct coord));
      h_grid->elev[i]=(short int *) calloc(maxj,sizeof(short int));
      h_grid->latlon[i]=(struct HRAP *) calloc(maxj,sizeof(struct HRAP));
      
      if(h_grid->box[i]==NULL || 
         h_grid->elev[i]==NULL || h_grid->latlon[i]==NULL) {
 
                printf("no memory for hrap array\n");
                exit(1);
 
          }
 
    }
 
for (i=0; i < h_grid->maxi-1; i++)
     {     
for (k=0; k < h_grid->maxj-1 ;k++)
     {
 
        irap.x=mini+i;
        irap.y=minj+k;
 
        h_grid->box[i][k].x=(short int)irap.x;
        h_grid->box[i][k].y=(short int)irap.y;
        
        hrap=HrapToLatLong(irap);
 
        h_grid->latlon[i][k].x=hrap.x;
        h_grid->latlon[i][k].y=hrap.y;     
/*
printf("%d %d %f %f\n",(short int)irap.x,(short int)irap.y,hrap.x,hrap.y);
*/
    
        iy=(topo->max_lat-hrap.y)/topo->delta_lat;
        ix=(topo->max_lon-hrap.x)/topo->delta_lon;
 
        if(ix <= 0 || iy <= 0 || ix >= topo->maxi || iy>= topo->maxj) {
 
                            h_grid->elev[i][k]=-1; 
                            continue;
 
              }
 
        distance=0.0;
        value=0.0;
 
        for(kk=ix;kk<=ix+1;kk++) {
      
        for(jj=iy;jj<=iy+1;jj++) {
 
           lat=topo->max_lat-(float)jj * topo->delta_lat;
           lon=topo->max_lon-(float)kk * topo->delta_lon;
 
           dist1=irap.y-lat;
           dist2=irap.x-lon;
 
           dist=pow(dist1,2)+pow(dist2,2);
 
           if(dist==0.0)
                      dist=1.0;
 
           dist=1/dist;
 
           value=value+dist*(float)topo->value[kk][jj];
           distance=distance+dist;
 
         }
             }
           
         elevation=value/distance;
         h_grid->elev[i][k]=elevation;
 
if(elevation > 500)
   printf("bad elevation %d %d %d %f %f\n",i,k,elevation,hrap.x,hrap.y);
  
  
 
        }
 
   }
 
return;
 
}