Geografic-Information-System/raster/r.li/r.li.padcv/padcv.c

/*
 * \brief calculates coefficient of variation of patch area 
 *
 *   \AUTHOR: Serena Pallecchi student of Computer Science University of Pisa (Italy)
 *                      Commission from Faunalia Pontedera (PI) www.faunalia.it
 *
 *   This program is free software under the GPL (>=v2)
 *   Read the COPYING file that comes with GRASS for details.
 *
 */

#include <grass/gis.h>
#include <grass/raster.h>
#include <grass/glocale.h>

#include <stdlib.h>
#include <fcntl.h>
#include <math.h>

#include "../r.li.daemon/defs.h"
#include "../r.li.daemon/avlDefs.h"
#include "../r.li.daemon/avlID.h"
#include "../r.li.daemon/GenericCell.h"
#include "../r.li.daemon/daemon.h"

int calculate(int fd, struct area_entry *ad, double *result);
int calculateD(int fd, struct area_entry *ad, double *result);
int calculateF(int fd, struct area_entry *ad, double *result);

int main(int argc, char *argv[])
{
    struct Option *raster, *conf, *output;
    struct GModule *module;

    G_gisinit(argv[0]);
    module = G_define_module();
    module->description =
	_("Calculates coefficient of variation of patch area on a raster map");
    G_add_keyword(_("raster"));
    G_add_keyword(_("landscape structure analysis"));
    G_add_keyword(_("patch index"));

    /* define options */
    raster = G_define_standard_option(G_OPT_R_INPUT);

    conf = G_define_standard_option(G_OPT_F_INPUT);
    conf->key = "config";
    conf->description = _("Configuration file");
    conf->required = YES;

    output = G_define_standard_option(G_OPT_R_OUTPUT);

    if (G_parser(argc, argv))
	exit(EXIT_FAILURE);
    return calculateIndex(conf->answer, patchAreaDistributionCV, NULL,
			  raster->answer, output->answer);
}

int patchAreaDistributionCV(int fd, char **par, struct area_entry *ad, double *result)
{
    double indice = 0;
    struct Cell_head hd;
    int ris = RLI_OK;

    Rast_get_cellhd(ad->raster, "", &hd);

    switch (ad->data_type) {
    case CELL_TYPE:

	{
	    ris = calculate(fd, ad, &indice);
	    break;
	}
    case DCELL_TYPE:

	{
	    ris = calculateD(fd, ad, &indice);
	    break;
	}
    case FCELL_TYPE:

	{
	    ris = calculateF(fd, ad, &indice);
	    break;
	}
    default:

	{
	    G_fatal_error("data type unknown");
	    return RLI_ERRORE;
	}
    }
    if (ris != RLI_OK) {
	*result = -1;
	return RLI_ERRORE;
    }
    *result = indice;
    return RLI_OK;
}

int calculate(int fd, struct area_entry *ad, double *result)
{
    CELL *buf;
    CELL *buf_sup;
    CELL corrCell;
    CELL precCell;
    CELL supCell;
    int i, j;
    int mask_fd = -1, *mask_buf;
    int ris = 0;
    int masked = FALSE;
    int areaPatch = 0;		/*if all cells are null areaPatch=0 */
    long npatch = 0;
    long tot = 0;
    long zero = 0;
    long totCorr = 0;
    long idCorr = 0;
    long lastId = 0;
    long doppi = 0;
    long np = 0;
    long *mask_patch_sup;
    long *mask_patch_corr;
    double indice = 0;
    double somma = 0;
    double area = 0;
    double mn = 0;
    double sd = 0;
    double cv = 0;
    avlID_tree albero = NULL;
    avlID_table *array = NULL;
    generic_cell gc;

    gc.t = CELL_TYPE;

    /* open mask if needed */
    if (ad->mask == 1) {
	if ((mask_fd = open(ad->mask_name, O_RDONLY, 0755)) < 0)
	    return RLI_ERRORE;
	mask_buf = G_malloc(ad->cl * sizeof(int));
	if (mask_buf == NULL) {
	    G_fatal_error("malloc mask_buf failed");
	    return RLI_ERRORE;
	}
	masked = TRUE;
    }
    mask_patch_sup = G_malloc(ad->cl * sizeof(long));
    if (mask_patch_sup == NULL) {
	G_fatal_error("malloc mask_patch_sup failed");
	return RLI_ERRORE;
    }
    mask_patch_corr = G_malloc(ad->cl * sizeof(long));
    if (mask_patch_corr == NULL) {
	G_fatal_error("malloc mask_patch_corr failed");
	return RLI_ERRORE;
    }
    buf_sup = Rast_allocate_c_buf();
    if (buf_sup == NULL) {
	G_fatal_error("malloc buf_sup failed");
	return RLI_ERRORE;
    }
    buf = Rast_allocate_c_buf();
    if (buf == NULL) {
	G_fatal_error("malloc buf failed");
	return RLI_ERRORE;
    }
    Rast_set_c_null_value(buf_sup + ad->x, ad->cl);	/*the first time buf_sup is all null */
    for (i = 0; i < ad->cl; i++) {
	mask_patch_sup[i] = 0;
	mask_patch_corr[i] = 0;
    }
    for (j = 0; j < ad->rl; j++)
	/*for each raster row */

    {
	if (j > 0) {
	    buf_sup = RLI_get_cell_raster_row(fd, j - 1 + ad->y, ad);
	}
	buf = RLI_get_cell_raster_row(fd, j + ad->y, ad);
	if (masked) {
	    if (read(mask_fd, mask_buf, (ad->cl * sizeof(int))) < 0) {
		G_fatal_error("mask read failed");
		return RLI_ERRORE;
	    }
	}
	Rast_set_c_null_value(&precCell, 1);
	for (i = 0; i < ad->cl; i++)
	    /* for each cell in the row */
	{
	    area++;
	    corrCell = buf[i + ad->x];
	    if (masked && mask_buf[i + ad->x] == 0) {
		Rast_set_c_null_value(&corrCell, 1);
		area--;
	    }
	    if (!(Rast_is_null_value(&corrCell, gc.t))) {
		areaPatch++;
		if (i > 0)
		    precCell = buf[i - 1 + ad->x];
		if (j == 0)
		    Rast_set_c_null_value(&supCell, 1);

		else
		    supCell = buf_sup[i + ad->x];

		if (corrCell != precCell)
		    /*        ?
		     *      1 2
		     * */
		{
		    if (corrCell != supCell) {
			/*        3
			 *      1 2
			 * */
			/*new patch */
			if (idCorr == 0) {	/*first found patch */
			    lastId = 1;
			    idCorr = 1;
			    totCorr = 1;
			    mask_patch_corr[i] = idCorr;
			}

			else
			    /*not first patch */
			    /* put in the tree the previous value */
			{
			    if (albero == NULL) {
				albero = avlID_make(idCorr, totCorr);
				if (albero == NULL) {
				    G_fatal_error("avlID_make error");
				    return RLI_ERRORE;
				}
				npatch++;
			    }

			    else
				/*tree not empty */
			    {
				ris = avlID_add(&albero, idCorr, totCorr);
				switch (ris) {
				case AVL_ERR:

				    {
					G_fatal_error("avlID_add error");
					return RLI_ERRORE;
				    }
				case AVL_ADD:

				    {
					npatch++;
					break;
				    }
				case AVL_PRES:

				    {
					break;
				    }
				default:

				    {
					G_fatal_error
					    ("avlID_add unknown error");
					return RLI_ERRORE;
				    }
				}
			    }
			    totCorr = 1;
			    lastId++;
			    idCorr = lastId;
			    mask_patch_corr[i] = idCorr;
			}
		    }

		    else
			/* current cell and upper cell are equal */
			/*        2
			 *      1 2
			 * */
		    {
			if (albero == NULL) {
			    albero = avlID_make(idCorr, totCorr);
			    if (albero == NULL) {
				G_fatal_error("avlID_make error");
				return RLI_ERRORE;
			    }
			    npatch++;
			}
			else {	/*tree not null */

			    ris = avlID_add(&albero, idCorr, totCorr);
			    switch (ris) {
			    case AVL_ERR:
				{
				    G_fatal_error("avlID_add error");
				    return RLI_ERRORE;
				}
			    case AVL_ADD:
				{
				    npatch++;
				    break;
				}
			    case AVL_PRES:
				{
				    break;
				}
			    default:
				{
				    G_fatal_error("avlID_add unknown error");
				    return RLI_ERRORE;
				}
			    }
			}

			idCorr = mask_patch_sup[i];
			mask_patch_corr[i] = idCorr;
			totCorr = 1;
		    }
		}
		else {		/*current cell and previuos cell are equal */
		    /*        ?
		     *      1 1
		     */

		    if (corrCell == supCell) {	/*current cell and upper cell are equal */
			/*        1
			 *      1 1
			 */
			if (mask_patch_sup[i] != mask_patch_corr[i - 1]) {
			    long r = 0;
			    long del = mask_patch_sup[i];


			    r = avlID_sub(&albero, del);	/*r=number of cell of patch removed */

			    if (r == 0) {
				G_fatal_error("avlID_sub error");
				return RLI_ERRORE;
			    }

			    /*Remove one patch because it makes part of a patch already found */
			    ris = avlID_add(&albero, idCorr, r);

			    switch (ris) {
			    case AVL_ERR:
				{
				    G_fatal_error("avlID_add error");
				    return RLI_ERRORE;
				}
			    case AVL_ADD:
				{
				    npatch++;
				    break;
				}
			    case AVL_PRES:
				{
				    break;
				}
			    default:
				{
				    G_fatal_error("avlID_add unknown error");
				    return RLI_ERRORE;
				}
			    }
			    r = i;
			    while (r < ad->cl) {
				if (mask_patch_sup[r] == del) {
				    mask_patch_sup[r] = idCorr;
				}

				r++;
			    }

			    mask_patch_corr[i] = idCorr;
			}
			else {
			    mask_patch_corr[i] = idCorr;
			}
		    }
		    else {	/*current cell and upper cell are not equal */
			/*        2
			 *      1 1
			 */
			mask_patch_corr[i] = idCorr;
		    }

		    totCorr++;
		}
	    }
	    else {		/*cell is null or is not to consider */

		mask_patch_corr[i] = 0;

	    }
	}

	{
	    int ii;
	    long c;

	    for (ii = 0; ii < ad->cl; ii++) {
		c = mask_patch_corr[ii];
		mask_patch_sup[ii] = c;
		mask_patch_corr[ii] = 0;
	    }
	}


    }




    if (areaPatch != 0) {
	if (albero == NULL) {
	    albero = avlID_make(idCorr, totCorr);
	    if (albero == NULL) {
		G_fatal_error("avlID_make error");
		return RLI_ERRORE;
	    }
	    npatch++;
	}

	else {
	    ris = avlID_add(&albero, idCorr, totCorr);
	    switch (ris) {
	    case AVL_ERR:

		{
		    G_fatal_error("avlID_add error");
		    return RLI_ERRORE;
		}
	    case AVL_ADD:

		{
		    npatch++;
		    break;
		}
	    case AVL_PRES:

		{
		    break;
		}
	    default:

		{
		    G_fatal_error("avlID_add unknown error");
		    return RLI_ERRORE;
		}
	    }
	}
	array = G_malloc(npatch * sizeof(avlID_tableRow));
	if (array == NULL) {
	    G_fatal_error("malloc array failed");
	    return RLI_ERRORE;
	}
	tot = avlID_to_array(albero, zero, array);
	if (tot != npatch) {
	    G_warning
		("avlID_to_array unaspected value. the result could be wrong");
	    return RLI_ERRORE;
	}
	for (i = 0; i < npatch; i++) {
	    if (array[i]->tot == 0) {
		doppi++;
	    }
	}
	np = npatch;
	npatch = npatch - doppi;
	mn = areaPatch / npatch;

	/* calculate summary */
	for (i = 0; i < np; i++) {
	    long areaPi = 0;
	    double diff;

	    if (array[i]->tot != 0) {
		ris = ris + array[i]->tot;
		areaPi = (double)array[i]->tot;
		diff = areaPi - mn;
		somma = somma + (diff * diff);
	    }
	}
	sd = sqrt(somma / npatch);
	cv = sd * 100 / mn;
	indice = cv;
	G_free(array);
    }

    else
	indice = (double)(-1);
    if (masked)
	G_free(mask_buf);
    G_free(mask_patch_sup);
    *result = indice;

    G_free(buf_sup);
    return RLI_OK;
}

int calculateD(int fd, struct area_entry *ad, double *result)
{
    DCELL *buf;
    DCELL *buf_sup;
    DCELL corrCell;
    DCELL precCell;
    DCELL supCell;
    int i, j;
    int mask_fd = -1, *mask_buf;
    int ris = 0;
    int masked = FALSE;
    int areaPatch = 0;		/*if all cells are null areaPatch=0 */
    long npatch = 0;
    long tot = 0;
    long zero = 0;
    long totCorr = 0;
    long idCorr = 0;
    long lastId = 0;
    long doppi = 0;
    long np = 0;
    long *mask_patch_sup;
    long *mask_patch_corr;
    double indice = 0;
    double somma = 0;
    double area = 0;
    double mn = 0;
    double sd = 0;
    double cv = 0;
    avlID_tree albero = NULL;
    avlID_table *array = NULL;
    generic_cell gc;

    gc.t = DCELL_TYPE;

    /* open mask if needed */
    if (ad->mask == 1) {
	if ((mask_fd = open(ad->mask_name, O_RDONLY, 0755)) < 0)
	    return RLI_ERRORE;
	mask_buf = G_malloc(ad->cl * sizeof(int));
	if (mask_buf == NULL) {
	    G_fatal_error("malloc mask_buf failed");
	    return RLI_ERRORE;
	}
	masked = TRUE;
    }
    mask_patch_sup = G_malloc(ad->cl * sizeof(long));
    if (mask_patch_sup == NULL) {
	G_fatal_error("malloc mask_patch_sup failed");
	return RLI_ERRORE;
    }
    mask_patch_corr = G_malloc(ad->cl * sizeof(long));
    if (mask_patch_corr == NULL) {
	G_fatal_error("malloc mask_patch_corr failed");
	return RLI_ERRORE;
    }
    buf_sup = Rast_allocate_d_buf();
    if (buf_sup == NULL) {
	G_fatal_error("malloc buf_sup failed");
	return RLI_ERRORE;
    }
    buf = Rast_allocate_d_buf();
    if (buf == NULL) {
	G_fatal_error("malloc buf failed");
	return RLI_ERRORE;
    }
    Rast_set_d_null_value(buf_sup + ad->x, ad->cl);	/*the first time buf_sup is all null */
    for (i = 0; i < ad->cl; i++) {
	mask_patch_sup[i] = 0;
	mask_patch_corr[i] = 0;
    }
    for (j = 0; j < ad->rl; j++)
	/*for each raster row */

    {
	if (j > 0) {
	    buf_sup = RLI_get_dcell_raster_row(fd, j - 1 + ad->y, ad);
	}
	buf = RLI_get_dcell_raster_row(fd, j + ad->y, ad);
	if (masked) {
	    if (read(mask_fd, mask_buf, (ad->cl * sizeof(int))) < 0) {
		G_fatal_error("mask read failed");
		return RLI_ERRORE;
	    }
	}
	Rast_set_d_null_value(&precCell, 1);
	for (i = 0; i < ad->cl; i++) {
	    /* for each dcell in the row */
	    area++;
	    corrCell = buf[i + ad->x];
	    if (masked && mask_buf[i + ad->x] == 0) {
		Rast_set_d_null_value(&corrCell, 1);
		area--;
	    }
	    if (!(Rast_is_null_value(&corrCell, gc.t))) {
		areaPatch++;
		if (i > 0)
		    precCell = buf[i - 1 + ad->x];
		if (j == 0)
		    Rast_set_d_null_value(&supCell, 1);

		else
		    supCell = buf_sup[i + ad->x];
		if (corrCell != precCell)
		    /*        ?
		     *      1 2
		     * */
		{
		    if (corrCell != supCell) {

			/*        3
			 *      1 2
			 * */
			/*new patch */
			if (idCorr == 0) {	/*first patch */
			    lastId = 1;
			    idCorr = 1;
			    totCorr = 1;
			    mask_patch_corr[i] = idCorr;
			}

			else
			    /*not first patch */
			    /* put in the tree the previous value */
			{
			    if (albero == NULL) {
				albero = avlID_make(idCorr, totCorr);
				if (albero == NULL) {
				    G_fatal_error("avlID_make error");
				    return RLI_ERRORE;
				}
				npatch++;
			    }

			    else
				/*tree not empty */
			    {
				ris = avlID_add(&albero, idCorr, totCorr);
				switch (ris) {
				case AVL_ERR:

				    {
					G_fatal_error("avlID_add error");
					return RLI_ERRORE;
				    }
				case AVL_ADD:

				    {
					npatch++;
					break;
				    }
				case AVL_PRES:

				    {
					break;
				    }
				default:

				    {
					G_fatal_error
					    ("avlID_add unknown error");
					return RLI_ERRORE;
				    }
				}
			    }
			    totCorr = 1;
			    lastId++;
			    idCorr = lastId;
			    mask_patch_corr[i] = idCorr;
			}
		    }

		    else
			/*current cell and upper cell are equal */
			/*        2
			 *      1 2
			 * */
		    {
			if (albero == NULL) {
			    albero = avlID_make(idCorr, totCorr);
			    if (albero == NULL) {
				G_fatal_error("avlID_make error");
				return RLI_ERRORE;
			    }
			    npatch++;
			}
			else {	/*tree not null */

			    ris = avlID_add(&albero, idCorr, totCorr);
			    switch (ris) {
			    case AVL_ERR:
				{
				    G_fatal_error("avlID_add error");
				    return RLI_ERRORE;
				}
			    case AVL_ADD:
				{
				    npatch++;
				    break;
				}
			    case AVL_PRES:
				{
				    break;
				}
			    default:
				{
				    G_fatal_error("avlID_add unknown error");
				    return RLI_ERRORE;
				}
			    }
			}

			idCorr = mask_patch_sup[i];
			mask_patch_corr[i] = idCorr;
			totCorr = 1;
		    }
		}
		else {		/*current cell and previuos cell are equal */
		    /*        ?
		     *      1 1
		     */

		    if (corrCell == supCell) {	/*current cell and upper cell are equal */
			/*        1
			 *      1 1
			 */
			if (mask_patch_sup[i] != mask_patch_corr[i - 1]) {
			    long r = 0;
			    long del = mask_patch_sup[i];


			    r = avlID_sub(&albero, del);	/*r=number of cell of patch removed */

			    if (r == 0) {
				G_fatal_error("avlID_sub error");
				return RLI_ERRORE;
			    }

			    /*Remove one patch because it makes part of a patch already found */
			    ris = avlID_add(&albero, idCorr, r);

			    switch (ris) {
			    case AVL_ERR:
				{
				    G_fatal_error("avlID_add error");
				    return RLI_ERRORE;
				}
			    case AVL_ADD:
				{
				    npatch++;
				    break;
				}
			    case AVL_PRES:
				{
				    break;
				}
			    default:
				{
				    G_fatal_error("avlID_add unknown error");
				    return RLI_ERRORE;
				}
			    }
			    r = i;
			    while (r < ad->cl) {
				if (mask_patch_sup[r] == del) {
				    mask_patch_sup[r] = idCorr;
				}

				r++;
			    }

			    mask_patch_corr[i] = idCorr;
			}
			else {
			    mask_patch_corr[i] = idCorr;
			}
		    }
		    else {	/*current cell and upper cell are not equal */
			/*        2
			 *      1 1
			 */
			mask_patch_corr[i] = idCorr;
		    }

		    totCorr++;
		}
	    }
	    else {		/*cell is null or is not to consider */

		mask_patch_corr[i] = 0;

	    }
	}

	{
	    int ii;
	    long c;

	    for (ii = 0; ii < ad->cl; ii++) {
		c = mask_patch_corr[ii];
		mask_patch_sup[ii] = c;
		mask_patch_corr[ii] = 0;
	    }
	}


    }



    if (areaPatch != 0) {
	if (albero == NULL) {
	    albero = avlID_make(idCorr, totCorr);
	    if (albero == NULL) {
		G_fatal_error("avlID_make error");
		return RLI_ERRORE;
	    }
	    npatch++;
	}

	else {
	    ris = avlID_add(&albero, idCorr, totCorr);
	    switch (ris) {
	    case AVL_ERR:

		{
		    G_fatal_error("avlID_add error");
		    return RLI_ERRORE;
		}
	    case AVL_ADD:

		{
		    npatch++;
		    break;
		}
	    case AVL_PRES:

		{
		    break;
		}
	    default:

		{
		    G_fatal_error("avlID_add unknown error");
		    return RLI_ERRORE;
		}
	    }
	}
	array = G_malloc(npatch * sizeof(avlID_tableRow));
	if (array == NULL) {
	    G_fatal_error("malloc array failed");
	    return RLI_ERRORE;
	}
	tot = avlID_to_array(albero, zero, array);
	if (tot != npatch) {
	    G_warning
		("avlID_to_array unaspected value. the result could be wrong");
	    return RLI_ERRORE;
	}
	for (i = 0; i < npatch; i++) {
	    if (array[i]->tot == 0) {
		doppi++;
	    }
	}
	np = npatch;
	npatch = npatch - doppi;
	mn = areaPatch / npatch;

	/* calculate summary */
	for (i = 0; i < np; i++) {
	    long areaPi = 0;
	    double diff;

	    if (array[i]->tot != 0) {
		ris = ris + array[i]->tot;
		areaPi = (double)array[i]->tot;
		diff = areaPi - mn;
		somma = somma + (diff * diff);
	    }
	}
	sd = sqrt(somma / npatch);
	cv = sd * 100 / mn;
	indice = cv;
	G_free(array);
    }

    else
	indice = (double)(-1);
    if (masked)
	G_free(mask_buf);
    G_free(mask_patch_sup);
    *result = indice;
    return RLI_OK;
}

int calculateF(int fd, struct area_entry *ad, double *result)
{
    FCELL *buf;
    FCELL *buf_sup;
    FCELL corrCell;
    FCELL precCell;
    FCELL supCell;
    int i, j;
    int mask_fd = -1, *mask_buf;
    int ris = 0;
    int masked = FALSE;
    int areaPatch = 0;		/*if all cells are null areaPatch=0 */
    long npatch = 0;
    long np = 0;
    long tot = 0;
    long zero = 0;
    long totCorr = 0;
    long idCorr = 0;
    long lastId = 0;
    long doppi = 0;
    long *mask_patch_sup;
    long *mask_patch_corr;
    double indice = 0;
    double somma = 0;
    double area = 0;
    double mn = 0;
    double sd = 0;
    double cv = 0;
    avlID_tree albero = NULL;
    avlID_table *array = NULL;
    generic_cell gc;

    gc.t = FCELL_TYPE;

    /* open mask if needed */
    if (ad->mask == 1) {
	if ((mask_fd = open(ad->mask_name, O_RDONLY, 0755)) < 0)
	    return RLI_ERRORE;
	mask_buf = G_malloc(ad->cl * sizeof(int));
	if (mask_buf == NULL) {
	    G_fatal_error("malloc mask_buf failed");
	    return RLI_ERRORE;
	}
	masked = TRUE;
    }
    mask_patch_sup = G_malloc(ad->cl * sizeof(long));
    if (mask_patch_sup == NULL) {
	G_fatal_error("malloc mask_patch_sup failed");
	return RLI_ERRORE;
    }
    mask_patch_corr = G_malloc(ad->cl * sizeof(long));
    if (mask_patch_corr == NULL) {
	G_fatal_error("malloc mask_patch_corr failed");
	return RLI_ERRORE;
    }
    buf_sup = Rast_allocate_f_buf();
    if (buf_sup == NULL) {
	G_fatal_error("malloc buf_sup failed");
	return RLI_ERRORE;
    }
    buf = Rast_allocate_f_buf();
    if (buf == NULL) {
	G_fatal_error("malloc buf failed");
	return RLI_ERRORE;
    }
    Rast_set_f_null_value(buf_sup + ad->x, ad->cl);	/*the first time buf_sup is all null */
    for (i = 0; i < ad->cl; i++) {
	mask_patch_sup[i] = 0;
	mask_patch_corr[i] = 0;
    }
    for (j = 0; j < ad->rl; j++)
	/*for each raster row */

    {
	if (j > 0) {
	    buf_sup = RLI_get_fcell_raster_row(fd, j - 1 + ad->y, ad);
	}
	buf = RLI_get_fcell_raster_row(fd, j + ad->y, ad);
	if (masked) {
	    if (read(mask_fd, mask_buf, (ad->cl * sizeof(int))) < 0) {
		G_fatal_error("mask read failed");
		return RLI_ERRORE;
	    }
	}
	Rast_set_f_null_value(&precCell, 1);
	for (i = 0; i < ad->cl; i++) {
	    /* for each fcell in the row */
	    area++;
	    corrCell = buf[i + ad->x];
	    if (masked && mask_buf[i + ad->x] == 0) {
		Rast_set_f_null_value(&corrCell, 1);
		area--;
	    }
	    if (!(Rast_is_null_value(&corrCell, gc.t))) {
		areaPatch++;
		if (i > 0)
		    precCell = buf[i - 1 + ad->x];
		if (j == 0)
		    Rast_set_f_null_value(&supCell, 1);

		else
		    supCell = buf_sup[i + ad->x];

		if (corrCell != precCell)
		    /*        ?
		     *      1 2
		     * */
		{
		    if (corrCell != supCell)
			/*        3
			 *      1 2
			 * */
		    {

			/*new patch */
			if (idCorr == 0) {	/*first patch */
			    lastId = 1;
			    idCorr = 1;
			    totCorr = 1;
			    mask_patch_corr[i] = idCorr;
			}

			else
			    /*not first patch */
			    /* put in the tree the previous value */
			{
			    if (albero == NULL) {
				albero = avlID_make(idCorr, totCorr);
				if (albero == NULL) {
				    G_fatal_error("avlID_make error");
				    return RLI_ERRORE;
				}
				npatch++;
			    }

			    else
				/*tree not empty */
			    {
				ris = avlID_add(&albero, idCorr, totCorr);
				switch (ris) {
				case AVL_ERR:

				    {
					G_fatal_error("avlID_add error");
					return RLI_ERRORE;
				    }
				case AVL_ADD:

				    {
					npatch++;
					break;
				    }
				case AVL_PRES:

				    {
					break;
				    }
				default:

				    {
					G_fatal_error
					    ("avlID_add unknown error");
					return RLI_ERRORE;
				    }
				}
			    }
			    totCorr = 1;
			    lastId++;
			    idCorr = lastId;
			    mask_patch_corr[i] = idCorr;
			}
		    }

		    else
			/*current cell and upper cell are equal */
			/*        2
			 *      1 2
			 * */
		    {
			if (albero == NULL) {
			    albero = avlID_make(idCorr, totCorr);
			    if (albero == NULL) {
				G_fatal_error("avlID_make error");
				return RLI_ERRORE;
			    }
			    npatch++;
			}
			else {	/*tree not null */

			    ris = avlID_add(&albero, idCorr, totCorr);
			    switch (ris) {
			    case AVL_ERR:
				{
				    G_fatal_error("avlID_add error");
				    return RLI_ERRORE;
				}
			    case AVL_ADD:
				{
				    npatch++;
				    break;
				}
			    case AVL_PRES:
				{
				    break;
				}
			    default:
				{
				    G_fatal_error("avlID_add unknown error");
				    return RLI_ERRORE;
				}
			    }
			}

			idCorr = mask_patch_sup[i];
			mask_patch_corr[i] = idCorr;
			totCorr = 1;
		    }
		}
		else {		/*current cell and previuos cell are equal */
		    /*        ?
		     *      1 1
		     */

		    if (corrCell == supCell) {	/*current cell and upper cell are equal */
			/*        1
			 *      1 1
			 */
			if (mask_patch_sup[i] != mask_patch_corr[i - 1]) {
			    long r = 0;
			    long del = mask_patch_sup[i];


			    r = avlID_sub(&albero, del);	/*r=number of cell of patch removed */

			    if (r == 0) {
				G_fatal_error("avlID_sub error");
				return RLI_ERRORE;
			    }

			    /*Remove one patch because it makes part of a patch already found */
			    ris = avlID_add(&albero, idCorr, r);

			    switch (ris) {
			    case AVL_ERR:
				{
				    G_fatal_error("avlID_add error");
				    return RLI_ERRORE;
				}
			    case AVL_ADD:
				{
				    npatch++;
				    break;
				}
			    case AVL_PRES:
				{
				    break;
				}
			    default:
				{
				    G_fatal_error("avlID_add unknown error");
				    return RLI_ERRORE;
				}
			    }
			    r = i;
			    while (r < ad->cl) {
				if (mask_patch_sup[r] == del) {
				    mask_patch_sup[r] = idCorr;
				}

				r++;
			    }

			    mask_patch_corr[i] = idCorr;
			}
			else {
			    mask_patch_corr[i] = idCorr;
			}
		    }
		    else {	/*current cell and upper cell are not equal */
			/*        2
			 *      1 1
			 */
			mask_patch_corr[i] = idCorr;
		    }

		    totCorr++;
		}
	    }
	    else {		/*cell is null or is not to consider */

		mask_patch_corr[i] = 0;

	    }
	}

	{
	    int ii;
	    long c;

	    for (ii = 0; ii < ad->cl; ii++) {
		c = mask_patch_corr[ii];
		mask_patch_sup[ii] = c;
		mask_patch_corr[ii] = 0;
	    }
	}


    }




    if (areaPatch != 0) {
	if (albero == NULL) {
	    albero = avlID_make(idCorr, totCorr);
	    if (albero == NULL) {
		G_fatal_error("avlID_make error");
		return RLI_ERRORE;
	    }
	    npatch++;
	}

	else {
	    ris = avlID_add(&albero, idCorr, totCorr);
	    switch (ris) {
	    case AVL_ERR:

		{
		    G_fatal_error("avlID_add error");
		    return RLI_ERRORE;
		}
	    case AVL_ADD:

		{
		    npatch++;
		    break;
		}
	    case AVL_PRES:

		{
		    break;
		}
	    default:

		{
		    G_fatal_error("avlID_add unknown error");
		    return RLI_ERRORE;
		}
	    }
	}
	array = G_malloc(npatch * sizeof(avlID_tableRow));
	if (array == NULL) {
	    G_fatal_error("malloc array failed");
	    return RLI_ERRORE;
	}
	tot = avlID_to_array(albero, zero, array);
	if (tot != npatch) {
	    G_warning
		("avlID_to_array unaspected value. the result could be wrong");
	    return RLI_ERRORE;
	}
	for (i = 0; i < npatch; i++) {
	    if (array[i]->tot == 0) {
		doppi++;
	    }
	}
	np = npatch;
	npatch = npatch - doppi;
	mn = areaPatch / npatch;

	/* calculate summary */
	for (i = 0; i < np; i++) {
	    long areaPi = 0;
	    double diff;

	    if (array[i]->tot != 0) {
		ris = ris + array[i]->tot;
		areaPi = (double)array[i]->tot;
		diff = areaPi - mn;
		somma = somma + (diff * diff);
	    }
	}
	sd = sqrt(somma / npatch);
	cv = sd * 100 / mn;
	indice = cv;
	G_free(array);
    }

    else
	indice = (double)(-1);
    if (masked)
	G_free(mask_buf);
    G_free(mask_patch_sup);
    *result = indice;
    return RLI_OK;
}