Geografic-Information-System/raster/r.statistics/o_distrib.c

#include <stdlib.h>
#include <unistd.h>
#include <grass/gis.h>
#include <grass/glocale.h>
#include "method.h"

#define STATS "r.stats"

/* function prototypes */
static int o_out(FILE *, long, long);


int o_distrib(const char *basemap, const char *covermap, const char *outputmap, int usecats)
{
    char *me = "o_distrib";
    char command[1024];
    long csum, area, catb, basecat, covercat;
    double sum, tot;
    long stat, cat, total_count;
    char *tempfile1, *tempfile2;
    FILE *fd1, *fd2;

    tempfile1 = G_tempfile();
    tempfile2 = G_tempfile();

    sprintf(command, "%s -cn input=\"%s,%s\" fs=space > %s", STATS, basemap,
	    covermap, tempfile1);

    if (stat = system(command)) {
	unlink(tempfile1);
	G_fatal_error(_("%s: running %s command"), me, STATS);
    }

    fd1 = fopen(tempfile1, "r");
    fd2 = fopen(tempfile2, "w");
    if (fd1 == NULL || fd2 == NULL) {
	unlink(tempfile1);
	unlink(tempfile2);
	G_fatal_error(_("%s: unable to open temporary file"), me);
    }
    o_out(fd2, 0L, 0);		/* force at least one reclass rule */

    catb = 0;
    csum = 0;
    /*    fprintf(stderr,"***** Stage 1 - Calculating sums ****\n"); */
    while (fscanf(fd1, "%ld %ld %ld", &basecat, &covercat, &area) == 3) {
	if (catb != basecat) {
	    o_out(fd2, catb, csum);
	    csum = 0;
	    catb = basecat;
	}
	csum += area;
    }
    o_out(fd2, catb, csum);

    rewind(fd1);
    freopen(tempfile2, "r", fd2);

    /*    fprintf(stderr,"***** Stage 2 - Calculating percents of values in cover  ****\n"); */

    catb = 0;
    tot = 0;
    total_count = 0;

    while (fscanf(fd1, "%ld %ld %ld", &basecat, &covercat, &area) == 3) {
	if (catb != basecat && basecat > 0) {
	    if (fscanf(fd2, "%ld %ld", &cat, &total_count) != 2)
		return (1);
	    catb = basecat;
	    /* fprintf(stderr,"Total (must be 100): %lf\n",tot); */
	    tot = 0;
	}

	if (basecat) {
	    sum = (double)(100.0 * area) / total_count;
	    fprintf(stderr, "%8ld %8ld %f\n", basecat, covercat, sum);
	    /*tot+=sum;
	       fprintf(stderr,"Area: %ld   Tot: %ld  totsum: %lf\n",area,total_count,tot); */
	}
    }

    fclose(fd1);
    fclose(fd2);
    unlink(tempfile1);
    unlink(tempfile2);

    return (stat);
}


static int o_out(FILE * fd, long cat, long sum)
{
    if (sum == 0 || cat == 0)
	return -1;
    fprintf(fd, "%ld %ld\n", cat, sum);

    return 0;
}