/*  aread8mn.c. Program to compute area contributing to each Pixel in DEM 
   for cell outflow based on d8 directions.
     
  David G Tarboton
  Utah State University   
  
  SINMAP package version 0.1 9/2/97   */
  

#include "lsm.h"

void main(int argc,char **argv)
{
   char pfile[MAXLN],afile[MAXLN], *ext;
   int err,nmain;
   double x=0., y=0.;
   
   if(argc < 2)
    {  
       printf("Usage:\n %s filename [outletx outlety]\n",argv[0]);
       printf("(The optional outletx and outlety are outlet coordinates\n");
       printf("for the area to be computed.  If they are not given, or are \n");
       printf("0 0 the whole file is computed.)\n");
       printf("The following are appended to the file names\n");
       printf("before the files are opened:\n");
       printf("p    D8 flow directions(Input)\n");
       printf("ad8    D8 area's in pixels\n");
       exit(0);  
    }
    ext=strrchr(argv[1],'.');
    if(ext == NULL)
	{
       sprintf(pfile,"%s%s",argv[1],"p");
      sprintf(afile,"%s%s",argv[1],"ad8");
	}
	else
	{
		nmain=strlen(argv[1])-strlen(ext);
		strncpy(afile,argv[1],nmain);
		strcat(afile,"ad8");
		strcat(afile,ext);
		strncpy(pfile,argv[1],nmain);
		strcat(pfile,"p");
		strcat(pfile,ext);
	}
    
    if(argc >2)
    {
       sscanf(argv[2],"%lf",&x);
       sscanf(argv[3],"%lf",&y);
    }
    if(err=aread8(pfile,afile,x,y) != 0)
        printf("area error %d\n",err);
}