Geografic-Information-System/raster/r.slope.aspect/main.c

/****************************************************************************
 *
 * MODULE:       r.slope.aspect
 * AUTHOR(S):    Michael Shapiro and 
 *               Olga Waupotitsch (original CERL contributors), 
 *               Markus Neteler <neteler itc.it>,
 *               Bernhard Reiter <bernhard intevation.de>, 
 *               Brad Douglas <rez touchofmadness.com>,
 *               Glynn Clements <glynn gclements.plus.com>,
 *               Hamish Bowman <hamish_b yahoo.com>,
 *               Jachym Cepicky <jachym les-ejk.cz>,
 *               Jan-Oliver Wagner <jan intevation.de>,
 *               Radim Blazek <radim.blazek gmail.com>
 * PURPOSE:      generates raster maps of slope, aspect, curvatures and
 *               first and second order partial derivatives from a raster map
 *               of true elevation values
 * COPYRIGHT:    (C) 1999-2011 by the GRASS Development Team
 *
 *               This program is free software under the GNU General Public
 *               License (>=v2). Read the file COPYING that comes with GRASS
 *               for details.
 *
 *****************************************************************************/
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <grass/gis.h>
#include <grass/raster.h>
#include <grass/glocale.h>

/* 10/99 from GMSL, updated to new GRASS 5 code style , changed default "prec" to float */


#define abs(x) ((x)<0?-(x):(x))


/**************************************************************************
 * input is from command line.
 * arguments are elevation file, slope file, aspect file, profile curvature
 * file and tangential curvature file
 * elevation filename required
 * either slope filename or aspect filename or profile curvature filename
 * or tangential curvature filename required
 * usage: r.slope.aspect [-av] elevation=input slope=output1 aspect=output2
 *	pcurv=output3 tcurv=output4 format=name prec=name zfactor=value
 *	min_slope=value dx=output5 dy=output6 dxx=output7 
 *      dyy=output8 dxy=output9
 * -a don't align window
 * -q quiet
 **************************************************************************/

/*  some changes made to code to retrieve correct distances when using
   lat/lon projection.  changes involve recalculating H and V. see
   comments within code.                                           */
/*  added colortables for topographic parameters and fixed 
 *  the sign bug for the second order derivatives (jh) */


int main(int argc, char *argv[])
{
    struct Categories cats;
    int elevation_fd;
    int aspect_fd;
    int slope_fd;
    int pcurv_fd;
    int tcurv_fd;
    int dx_fd;
    int dy_fd;
    int dxx_fd;
    int dyy_fd;
    int dxy_fd;
    DCELL *elev_cell[3], *temp;
    DCELL *c1, *c2, *c3, *c4, *c5, *c6, *c7, *c8, *c9;
    DCELL tmp1, tmp2;
    FCELL dat1, dat2;
    CELL cat;
    void *asp_raster, *asp_ptr = NULL;
    void *slp_raster, *slp_ptr = NULL;
    void *pcurv_raster, *pcurv_ptr = NULL;
    void *tcurv_raster, *tcurv_ptr = NULL;
    void *dx_raster, *dx_ptr = NULL;
    void *dy_raster, *dy_ptr = NULL;
    void *dxx_raster, *dxx_ptr = NULL;
    void *dyy_raster, *dyy_ptr = NULL;
    void *dxy_raster, *dxy_ptr = NULL;
    int i;
    RASTER_MAP_TYPE out_type, data_type;
    int Wrap;			/* global wraparound */
    struct Cell_head window, cellhd;
    struct History hist;
    struct Colors colors;

    const char *elev_name;
    const char *aspect_name;
    const char *slope_name;
    const char *pcurv_name;
    const char *tcurv_name;
    const char *dx_name;
    const char *dy_name;
    const char *dxx_name;
    const char *dyy_name;
    const char *dxy_name;
    char buf[300];
    int nrows, row;
    int ncols, col;

    double north, east, south, west, ns_med;

    double radians_to_degrees;
    double degrees_to_radians;
    double H, V;
    double dx;			/* partial derivative in ew direction */
    double dy;			/* partial derivative in ns direction */
    double dxx, dxy, dyy;
    double s3, s4, s5, s6;
    double pcurv, tcurv;
    double scik1 = 100000.;
    double zfactor;
    double factor;
    double aspect, min_asp = 360., max_asp = 0.;
    double dnorm1, dx2, dy2, grad2, grad, dxy2;
    double gradmin = 0.001;
    double c1min = 0., c1max = 0., c2min = 0., c2max = 0.;

    double answer[92];
    double degrees;
    double tan_ans;
    double key;
    double slp_in_perc, slp_in_deg;
    double min_slp = 900., max_slp = 0., min_slope;
    int low, hi, test = 0;
    int deg = 0;
    int perc = 0;
    char *slope_fmt;
    struct GModule *module;
    struct
    {
	struct Option *elevation, *slope_fmt, *slope, *aspect, *pcurv, *tcurv,
	    *zfactor, *min_slope, *out_precision,
	    *dx, *dy, *dxx, *dyy, *dxy;
    } parm;
    struct
    {
	struct Flag *a;
    } flag;

    G_gisinit(argv[0]);

    module = G_define_module();
    G_add_keyword(_("raster"));
    G_add_keyword(_("terrain"));
    G_add_keyword(_("aspect"));
    G_add_keyword(_("slope"));
    G_add_keyword(_("curvature"));
    module->label = _("Generates raster maps of slope, aspect, curvatures and "
		      "partial derivatives from an elevation raster map.");
    module->description = _("Aspect is calculated counterclockwise from east.");
    
    parm.elevation = G_define_standard_option(G_OPT_R_ELEV);

    parm.slope = G_define_standard_option(G_OPT_R_OUTPUT);
    parm.slope->key = "slope";
    parm.slope->required = NO;
    parm.slope->description = _("Name for output slope raster map");
    parm.slope->guisection = _("Outputs");

    parm.aspect = G_define_standard_option(G_OPT_R_OUTPUT);
    parm.aspect->key = "aspect";
    parm.aspect->required = NO;
    parm.aspect->description = _("Name for output aspect raster map");
    parm.aspect->guisection = _("Outputs");

    parm.slope_fmt = G_define_option();
    parm.slope_fmt->key = "format";
    parm.slope_fmt->type = TYPE_STRING;
    parm.slope_fmt->required = NO;
    parm.slope_fmt->answer = "degrees";
    parm.slope_fmt->options = "degrees,percent";
    parm.slope_fmt->description = _("Format for reporting the slope");
    parm.slope_fmt->guisection = _("Settings");

    parm.out_precision = G_define_option();
    parm.out_precision->key = "precision";
    parm.out_precision->type = TYPE_STRING;
    parm.out_precision->options = "CELL,FCELL,DCELL";
    parm.out_precision->description =
	_("Type of output aspect and slope maps");
    parm.out_precision->answer = "FCELL";
    parm.out_precision->guisection = _("Settings");

    parm.pcurv = G_define_standard_option(G_OPT_R_OUTPUT);
    parm.pcurv->key = "pcurvature";
    parm.pcurv->required = NO;
    parm.pcurv->description =
	_("Name for output profile curvature raster map");
    parm.pcurv->guisection = _("Outputs");

    parm.tcurv = G_define_standard_option(G_OPT_R_OUTPUT);
    parm.tcurv->key = "tcurvature";
    parm.tcurv->required = NO;
    parm.tcurv->description =
	_("Name for output tangential curvature raster map");
    parm.tcurv->guisection = _("Outputs");

    parm.dx = G_define_standard_option(G_OPT_R_OUTPUT);
    parm.dx->key = "dx";
    parm.dx->required = NO;
    parm.dx->description =
	_("Name for output first order partial derivative dx (E-W slope) raster map");
    parm.dx->guisection = _("Outputs");

    parm.dy = G_define_standard_option(G_OPT_R_OUTPUT);
    parm.dy->key = "dy";
    parm.dy->required = NO;
    parm.dy->description =
	_("Name for output first order partial derivative dy (N-S slope) raster map");
    parm.dy->guisection = _("Outputs");

    parm.dxx = G_define_standard_option(G_OPT_R_OUTPUT);
    parm.dxx->key = "dxx";
    parm.dxx->required = NO;
    parm.dxx->description =
	_("Name for output second order partial derivative dxx raster map");
    parm.dxx->guisection = _("Outputs");

    parm.dyy = G_define_standard_option(G_OPT_R_OUTPUT);
    parm.dyy->key = "dyy";
    parm.dyy->required = NO;
    parm.dyy->description =
	_("Name for output second order partial derivative dyy raster map");
    parm.dyy->guisection = _("Outputs");

    parm.dxy = G_define_standard_option(G_OPT_R_OUTPUT);
    parm.dxy->key = "dxy";
    parm.dxy->required = NO;
    parm.dxy->description =
	_("Name for output second order partial derivative dxy raster map");
    parm.dxy->guisection = _("Outputs");

    parm.zfactor = G_define_option();
    parm.zfactor->key = "zscale";
    parm.zfactor->description =
	_("Multiplicative factor to convert elevation units to meters");
    parm.zfactor->type = TYPE_DOUBLE;
    parm.zfactor->required = NO;
    parm.zfactor->answer = "1.0";
    parm.zfactor->guisection = _("Settings");

    parm.min_slope = G_define_option();
    parm.min_slope->key = "min_slope";
    parm.min_slope->description =
	_("Minimum slope value (in percent) for which aspect is computed");
    parm.min_slope->type = TYPE_DOUBLE;
    parm.min_slope->required = NO;
    parm.min_slope->answer = "0.0";
    parm.min_slope->guisection = _("Settings");

    flag.a = G_define_flag();
    flag.a->key = 'a';
    flag.a->description =
	_("Do not align the current region to the raster elevation map");
    flag.a->guisection = _("Settings");


    if (G_parser(argc, argv))
	exit(EXIT_FAILURE);


    radians_to_degrees = 180.0 / M_PI;
    degrees_to_radians = M_PI / 180.0;

    /* INC BY ONE
       answer[0] = 0.0;
       answer[91] = 15000.0;

       for (i = 1; i < 91; i++)
       {
       degrees = i - .5;
       tan_ans = tan ( degrees  / radians_to_degrees );
       answer[i] = tan_ans * tan_ans;
       }
     */
    answer[0] = 0.0;
    answer[90] = 15000.0;

    for (i = 0; i < 90; i++) {
	degrees = i + .5;
	tan_ans = tan(degrees / radians_to_degrees);
	answer[i] = tan_ans * tan_ans;
    }


    elev_name = parm.elevation->answer;
    slope_name = parm.slope->answer;
    aspect_name = parm.aspect->answer;
    pcurv_name = parm.pcurv->answer;
    tcurv_name = parm.tcurv->answer;
    dx_name = parm.dx->answer;
    dy_name = parm.dy->answer;
    dxx_name = parm.dxx->answer;
    dyy_name = parm.dyy->answer;
    dxy_name = parm.dxy->answer;

    G_check_input_output_name(elev_name, slope_name, G_FATAL_EXIT);
    G_check_input_output_name(elev_name, aspect_name, G_FATAL_EXIT);
    G_check_input_output_name(elev_name, pcurv_name, G_FATAL_EXIT);
    G_check_input_output_name(elev_name, tcurv_name, G_FATAL_EXIT);
    G_check_input_output_name(elev_name, dx_name, G_FATAL_EXIT);
    G_check_input_output_name(elev_name, dy_name, G_FATAL_EXIT);
    G_check_input_output_name(elev_name, dxx_name, G_FATAL_EXIT);
    G_check_input_output_name(elev_name, dyy_name, G_FATAL_EXIT);
    G_check_input_output_name(elev_name, dxy_name, G_FATAL_EXIT);

    if (sscanf(parm.zfactor->answer, "%lf", &zfactor) != 1 || zfactor <= 0.0) {
	G_fatal_error(_("%s=%s - must be a positive number"),
		      parm.zfactor->key, parm.zfactor->answer);
    }

    if (sscanf(parm.min_slope->answer, "%lf", &min_slope) != 1 ||
	min_slope < 0.0) {
	G_fatal_error(_("%s=%s - must be a non-negative number"),
		      parm.min_slope->key,
		      parm.min_slope->answer);
    }

    slope_fmt = parm.slope_fmt->answer;
    if (strcmp(slope_fmt, "percent") == 0)
	perc = 1;
    else if (strcmp(slope_fmt, "degrees") == 0)
	deg = 1;

    if (slope_name == NULL && aspect_name == NULL
	&& pcurv_name == NULL && tcurv_name == NULL
	&& dx_name == NULL && dy_name == NULL
	&& dxx_name == NULL && dyy_name == NULL && dxy_name == NULL) {
	G_fatal_error(_("You must specify at least one of the parameters: "
			"<%s>, <%s>, <%s>, <%s>, <%s>, <%s>, <%s>, <%s> or <%s>"),
		      parm.slope->key, parm.aspect->key, parm.pcurv->key,
		      parm.tcurv->key, parm.dx->key, parm.dy->key,
		      parm.dxx->key, parm.dyy->key, parm.dxy->key);
    }

    /* set the window from the header for the elevation file */
    if (!flag.a->answer) {
	G_get_window(&window);
	Rast_get_cellhd(elev_name, "", &cellhd);
	Rast_align_window(&window, &cellhd);
	Rast_set_window(&window);
    }

    if (strcmp(parm.out_precision->answer, "DCELL") == 0)
	out_type = DCELL_TYPE;
    else if (strcmp(parm.out_precision->answer, "FCELL") == 0)
	out_type = FCELL_TYPE;
    else if (strcmp(parm.out_precision->answer, "CELL") == 0)
	out_type = CELL_TYPE;
    else
	G_fatal_error(_("Wrong raster type: %s"), parm.out_precision->answer);

    data_type = out_type;
    /* data type is the type of data being processed,
       out_type is type of map being created */
    /* ? why not use Rast_map_type() then ? */

    G_get_set_window(&window);

    nrows = Rast_window_rows();
    ncols = Rast_window_cols();

    if (((window.west == (window.east - 360.))
	 || (window.east == (window.west - 360.))) &&
	(G_projection() == PROJECTION_LL)) {
	Wrap = 1;
	ncols += 2;
    }
    else
	Wrap = 0;

    /* H = window.ew_res * 4 * 2/ zfactor; *//* horizontal (east-west) run 
       times 4 for weighted difference */
    /* V = window.ns_res * 4 * 2/ zfactor; *//* vertical (north-south) run 
       times 4 for weighted difference */

    /* give warning if location units are different from meters and zfactor=1 */
    factor = G_database_units_to_meters_factor();
    if (factor != 1.0)
	G_warning(_("Converting units to meters, factor=%.6f"), factor);

    G_begin_distance_calculations();
    north = Rast_row_to_northing(0.5, &window);
    ns_med = Rast_row_to_northing(1.5, &window);
    south = Rast_row_to_northing(2.5, &window);
    east = Rast_col_to_easting(2.5, &window);
    west = Rast_col_to_easting(0.5, &window);
    V = G_distance(east, north, east, south) * 4 / zfactor;
    H = G_distance(east, ns_med, west, ns_med) * 4 / zfactor;
    /*    ____________________________
       |c1      |c2      |c3      |
       |        |        |        |
       |        |  north |        |        
       |        |        |        |
       |________|________|________|          
       |c4      |c5      |c6      |
       |        |        |        |
       |  east  | ns_med |  west  |
       |        |        |        |
       |________|________|________|
       |c7      |c8      |c9      |
       |        |        |        |
       |        |  south |        |
       |        |        |        |
       |________|________|________|
     */

    /* open the elevation file for reading */
    elevation_fd = Rast_open_old(elev_name, "");
    elev_cell[0] = (DCELL *) G_calloc(ncols + 1, sizeof(DCELL));
    Rast_set_d_null_value(elev_cell[0], ncols);
    elev_cell[1] = (DCELL *) G_calloc(ncols + 1, sizeof(DCELL));
    Rast_set_d_null_value(elev_cell[1], ncols);
    elev_cell[2] = (DCELL *) G_calloc(ncols + 1, sizeof(DCELL));
    Rast_set_d_null_value(elev_cell[2], ncols);

    if (slope_name != NULL) {
	slope_fd = Rast_open_new(slope_name, out_type);
	slp_raster = Rast_allocate_buf(data_type);
	Rast_set_null_value(slp_raster, Rast_window_cols(), data_type);
	Rast_put_row(slope_fd, slp_raster, data_type);
    }
    else {
	slp_raster = NULL;
	slope_fd = -1;
    }

    if (aspect_name != NULL) {
	aspect_fd = Rast_open_new(aspect_name, out_type);
	asp_raster = Rast_allocate_buf(data_type);
	Rast_set_null_value(asp_raster, Rast_window_cols(), data_type);
	Rast_put_row(aspect_fd, asp_raster, data_type);
    }
    else {
	asp_raster = NULL;
	aspect_fd = -1;
    }

    if (pcurv_name != NULL) {
	pcurv_fd = Rast_open_new(pcurv_name, out_type);
	pcurv_raster = Rast_allocate_buf(data_type);
	Rast_set_null_value(pcurv_raster, Rast_window_cols(), data_type);
	Rast_put_row(pcurv_fd, pcurv_raster, data_type);
    }
    else {
	pcurv_raster = NULL;
	pcurv_fd = -1;
    }

    if (tcurv_name != NULL) {
	tcurv_fd = Rast_open_new(tcurv_name, out_type);
	tcurv_raster = Rast_allocate_buf(data_type);
	Rast_set_null_value(tcurv_raster, Rast_window_cols(), data_type);
	Rast_put_row(tcurv_fd, tcurv_raster, data_type);
    }
    else {
	tcurv_raster = NULL;
	tcurv_fd = -1;
    }

    if (dx_name != NULL) {
	dx_fd = Rast_open_new(dx_name, out_type);
	dx_raster = Rast_allocate_buf(data_type);
	Rast_set_null_value(dx_raster, Rast_window_cols(), data_type);
	Rast_put_row(dx_fd, dx_raster, data_type);
    }
    else {
	dx_raster = NULL;
	dx_fd = -1;
    }

    if (dy_name != NULL) {
	dy_fd = Rast_open_new(dy_name, out_type);
	dy_raster = Rast_allocate_buf(data_type);
	Rast_set_null_value(dy_raster, Rast_window_cols(), data_type);
	Rast_put_row(dy_fd, dy_raster, data_type);
    }
    else {
	dy_raster = NULL;
	dy_fd = -1;
    }

    if (dxx_name != NULL) {
	dxx_fd = Rast_open_new(dxx_name, out_type);
	dxx_raster = Rast_allocate_buf(data_type);
	Rast_set_null_value(dxx_raster, Rast_window_cols(), data_type);
	Rast_put_row(dxx_fd, dxx_raster, data_type);
    }
    else {
	dxx_raster = NULL;
	dxx_fd = -1;
    }

    if (dyy_name != NULL) {
	dyy_fd = Rast_open_new(dyy_name, out_type);
	dyy_raster = Rast_allocate_buf(data_type);
	Rast_set_null_value(dyy_raster, Rast_window_cols(), data_type);
	Rast_put_row(dyy_fd, dyy_raster, data_type);
    }
    else {
	dyy_raster = NULL;
	dyy_fd = -1;
    }

    if (dxy_name != NULL) {
	dxy_fd = Rast_open_new(dxy_name, out_type);
	dxy_raster = Rast_allocate_buf(data_type);
	Rast_set_null_value(dxy_raster, Rast_window_cols(), data_type);
	Rast_put_row(dxy_fd, dxy_raster, data_type);
    }
    else {
	dxy_raster = NULL;
	dxy_fd = -1;
    }

    if (aspect_fd < 0 && slope_fd < 0 && pcurv_fd < 0 && tcurv_fd < 0
	&& dx_fd < 0 && dy_fd < 0 && dxx_fd < 0 && dyy_fd < 0 && dxy_fd < 0)
	exit(EXIT_FAILURE);

    if (Wrap) {
	Rast_get_d_row_nomask(elevation_fd, elev_cell[1] + 1, 0);
	elev_cell[1][0] = elev_cell[1][Rast_window_cols() - 1];
	elev_cell[1][Rast_window_cols() + 1] = elev_cell[1][2];
    }
    else
	Rast_get_d_row_nomask(elevation_fd, elev_cell[1], 0);

    if (Wrap) {
	Rast_get_d_row_nomask(elevation_fd, elev_cell[2] + 1, 1);
	elev_cell[2][0] = elev_cell[2][Rast_window_cols() - 1];
	elev_cell[2][Rast_window_cols() + 1] = elev_cell[2][2];
    }
    else
	Rast_get_d_row_nomask(elevation_fd, elev_cell[2], 1);

    G_verbose_message(_("Percent complete..."));

    for (row = 2; row < nrows; row++) {
	/*  if projection is Lat/Lon, recalculate  V and H   */
	if (G_projection() == PROJECTION_LL) {
	    north = Rast_row_to_northing((row - 2 + 0.5), &window);
	    ns_med = Rast_row_to_northing((row - 1 + 0.5), &window);
	    south = Rast_row_to_northing((row + 0.5), &window);
	    east = Rast_col_to_easting(2.5, &window);
	    west = Rast_col_to_easting(0.5, &window);
	    V = G_distance(east, north, east, south) * 4 / zfactor;
	    H = G_distance(east, ns_med, west, ns_med) * 4 / zfactor;
	    /*        ____________________________
	       |c1      |c2      |c3      |
	       |        |        |        |
	       |        |  north |        |        
	       |        |        |        |
	       |________|________|________|          
	       |c4      |c5      |c6      |
	       |        |        |        |
	       |  east  | ns_med |  west  |
	       |        |        |        |
	       |________|________|________|
	       |c7      |c8      |c9      |
	       |        |        |        |
	       |        |  south |        |
	       |        |        |        |
	       |________|________|________|
	     */
	}

	G_percent(row, nrows, 2);
	temp = elev_cell[0];
	elev_cell[0] = elev_cell[1];
	elev_cell[1] = elev_cell[2];
	elev_cell[2] = temp;

	if (Wrap) {
	    Rast_get_d_row_nomask(elevation_fd, elev_cell[2] + 1, row);
	    elev_cell[2][0] = elev_cell[2][Rast_window_cols() - 1];
	    elev_cell[2][Rast_window_cols() + 1] = elev_cell[2][2];
	}
	else
	    Rast_get_d_row_nomask(elevation_fd, elev_cell[2], row);

	c1 = elev_cell[0];
	c2 = c1 + 1;
	c3 = c1 + 2;
	c4 = elev_cell[1];
	c5 = c4 + 1;
	c6 = c4 + 2;
	c7 = elev_cell[2];
	c8 = c7 + 1;
	c9 = c7 + 2;

	if (aspect_fd >= 0) {
	    if (Wrap)
		asp_ptr = asp_raster;
	    else
		asp_ptr =
		    G_incr_void_ptr(asp_raster, Rast_cell_size(data_type));
	}
	if (slope_fd >= 0) {
	    if (Wrap)
		slp_ptr = slp_raster;
	    else
		slp_ptr =
		    G_incr_void_ptr(slp_raster, Rast_cell_size(data_type));
	}

	if (pcurv_fd >= 0) {
	    if (Wrap)
		pcurv_ptr = pcurv_raster;
	    else
		pcurv_ptr =
		    G_incr_void_ptr(pcurv_raster, Rast_cell_size(data_type));
	}

	if (tcurv_fd >= 0) {
	    if (Wrap)
		tcurv_ptr = tcurv_raster;
	    else
		tcurv_ptr =
		    G_incr_void_ptr(tcurv_raster, Rast_cell_size(data_type));
	}

	if (dx_fd >= 0) {
	    if (Wrap)
		dx_ptr = dx_raster;
	    else
		dx_ptr = G_incr_void_ptr(dx_raster, Rast_cell_size(data_type));
	}

	if (dy_fd >= 0) {
	    if (Wrap)
		dy_ptr = dy_raster;
	    else
		dy_ptr = G_incr_void_ptr(dy_raster, Rast_cell_size(data_type));
	}

	if (dxx_fd >= 0) {
	    if (Wrap)
		dxx_ptr = dxx_raster;
	    else
		dxx_ptr =
		    G_incr_void_ptr(dxx_raster, Rast_cell_size(data_type));
	}

	if (dyy_fd >= 0) {
	    if (Wrap)
		dyy_ptr = dyy_raster;
	    else
		dyy_ptr =
		    G_incr_void_ptr(dyy_raster, Rast_cell_size(data_type));
	}

	if (dxy_fd >= 0) {
	    if (Wrap)
		dxy_ptr = dxy_raster;
	    else
		dxy_ptr =
		    G_incr_void_ptr(dxy_raster, Rast_cell_size(data_type));
	}


	/*skip first cell of the row */

	for (col = ncols - 2; col-- > 0;
	     c1++, c2++, c3++, c4++, c5++, c6++, c7++, c8++, c9++) {
	    /*  DEBUG:
	       fprintf(stdout, "\n%.0f %.0f %.0f\n%.0f %.0f %.0f\n%.0f %.0f %.0f\n",
	       *c1, *c2, *c3, *c4, *c5, *c6, *c7, *c8, *c9);
	     */

	    if (Rast_is_d_null_value(c1) || Rast_is_d_null_value(c2) ||
		Rast_is_d_null_value(c3) || Rast_is_d_null_value(c4) ||
		Rast_is_d_null_value(c5) || Rast_is_d_null_value(c6) ||
		Rast_is_d_null_value(c7) || Rast_is_d_null_value(c8) ||
		Rast_is_d_null_value(c9)) {
		if (slope_fd > 0) {
		    Rast_set_null_value(slp_ptr, 1, data_type);
		    slp_ptr =
			G_incr_void_ptr(slp_ptr, Rast_cell_size(data_type));
		}
		if (aspect_fd > 0) {
		    Rast_set_null_value(asp_ptr, 1, data_type);
		    asp_ptr =
			G_incr_void_ptr(asp_ptr, Rast_cell_size(data_type));
		}
		if (pcurv_fd > 0) {
		    Rast_set_null_value(pcurv_ptr, 1, data_type);
		    pcurv_ptr =
			G_incr_void_ptr(pcurv_ptr, Rast_cell_size(data_type));
		}
		if (tcurv_fd > 0) {
		    Rast_set_null_value(tcurv_ptr, 1, data_type);
		    tcurv_ptr =
			G_incr_void_ptr(tcurv_ptr, Rast_cell_size(data_type));
		}
		if (dx_fd > 0) {
		    Rast_set_null_value(dx_ptr, 1, data_type);
		    dx_ptr =
			G_incr_void_ptr(dx_ptr, Rast_cell_size(data_type));
		}
		if (dy_fd > 0) {
		    Rast_set_null_value(dy_ptr, 1, data_type);
		    dy_ptr =
			G_incr_void_ptr(dy_ptr, Rast_cell_size(data_type));
		}
		if (dxx_fd > 0) {
		    Rast_set_null_value(dxx_ptr, 1, data_type);
		    dxx_ptr =
			G_incr_void_ptr(dxx_ptr, Rast_cell_size(data_type));
		}
		if (dyy_fd > 0) {
		    Rast_set_null_value(dyy_ptr, 1, data_type);
		    dyy_ptr =
			G_incr_void_ptr(dyy_ptr, Rast_cell_size(data_type));
		}
		if (dxy_fd > 0) {
		    Rast_set_null_value(dxy_ptr, 1, data_type);
		    dxy_ptr =
			G_incr_void_ptr(dxy_ptr, Rast_cell_size(data_type));
		}
		continue;
	    }			/* no data */

	    dx = ((*c1 + *c4 + *c4 + *c7) - (*c3 + *c6 + *c6 + *c9)) / H;
	    dy = ((*c7 + *c8 + *c8 + *c9) - (*c1 + *c2 + *c2 + *c3)) / V;

	    /* compute topographic parameters */
	    key = dx * dx + dy * dy;
	    slp_in_perc = 100 * sqrt(key);
	    slp_in_deg = atan(sqrt(key)) * radians_to_degrees;

	    /* now update min and max */
	    if (deg) {
		if (min_slp > slp_in_deg)
		    min_slp = slp_in_deg;
		if (max_slp < slp_in_deg)
		    max_slp = slp_in_deg;
	    }
	    else {
		if (min_slp > slp_in_perc)
		    min_slp = slp_in_perc;
		if (max_slp < slp_in_perc)
		    max_slp = slp_in_perc;
	    }
	    if (slp_in_perc < min_slope)
		slp_in_perc = 0.;

	    if (deg && out_type == CELL_TYPE) {
		/* INC BY ONE
		   low = 1;
		   hi = 91;
		 */
		low = 0;
		hi = 90;
		test = 20;

		while (hi >= low) {
		    if (key >= answer[test])
			low = test + 1;
		    else if (key < answer[test - 1])
			hi = test - 1;
		    else
			break;
		    test = (low + hi) / 2;
		}
	    }
	    else if (perc && out_type == CELL_TYPE)
		/* INCR_BY_ONE */
		/* test = slp_in_perc + 1.5; *//* All the slope categories are
		   incremented by 1 */
		test = slp_in_perc + .5;

	    if (slope_fd > 0) {
		if (data_type == CELL_TYPE)
		    *((CELL *) slp_ptr) = (CELL) test;
		else {
		    if (deg)
			Rast_set_d_value(slp_ptr,
					     (DCELL) slp_in_deg, data_type);
		    else
			Rast_set_d_value(slp_ptr,
					     (DCELL) slp_in_perc, data_type);
		}
		slp_ptr = G_incr_void_ptr(slp_ptr, Rast_cell_size(data_type));
	    }			/* computing slope */

	    if (aspect_fd > 0) {
		if (key == 0.)
		    aspect = 0.;
		else if (dx == 0) {
		    if (dy > 0)
			aspect = 90.;
		    else
			aspect = 270.;
		}
		else {
		    aspect = (atan2(dy, dx) / degrees_to_radians);
		    if ((aspect <= 0.5) && (aspect > 0) &&
			out_type == CELL_TYPE)
			aspect = 360.;
		    if (aspect <= 0.)
			aspect = 360. + aspect;
		}

		/* if it's not the case that the slope for this cell 
		   is below specified minimum */
		if (!((slope_fd > 0) && (slp_in_perc < min_slope))) {
		    if (out_type == CELL_TYPE)
			*((CELL *) asp_ptr) = (CELL) (aspect + .5);
		    else
			Rast_set_d_value(asp_ptr,
					     (DCELL) aspect, data_type);
		}
		else
		    Rast_set_null_value(asp_ptr, 1, data_type);
		asp_ptr = G_incr_void_ptr(asp_ptr, Rast_cell_size(data_type));

		/* now update min and max */
		if (min_asp > aspect)
		    min_asp = aspect;
		if (max_asp < aspect)
		    max_asp = aspect;
	    }			/* computing aspect */

	    if (dx_fd > 0) {
		if (out_type == CELL_TYPE)
		    *((CELL *) dx_ptr) = (CELL) (scik1 * dx);
		else
		    Rast_set_d_value(dx_ptr, (DCELL) dx, data_type);
		dx_ptr = G_incr_void_ptr(dx_ptr, Rast_cell_size(data_type));
	    }

	    if (dy_fd > 0) {
		if (out_type == CELL_TYPE)
		    *((CELL *) dy_ptr) = (CELL) (scik1 * dy);
		else
		    Rast_set_d_value(dy_ptr, (DCELL) dy, data_type);
		dy_ptr = G_incr_void_ptr(dy_ptr, Rast_cell_size(data_type));
	    }

	    if (dxx_fd <= 0 && dxy_fd <= 0 && dyy_fd <= 0 &&
		pcurv_fd <= 0 && tcurv_fd <= 0)
		continue;

	    /* compute second order derivatives */
	    s4 = *c1 + *c3 + *c7 + *c9 - *c5 * 8.;
	    s5 = *c4 * 4. + *c6 * 4. - *c8 * 2. - *c2 * 2.;
	    s6 = *c8 * 4. + *c2 * 4. - *c4 * 2. - *c6 * 2.;
	    s3 = *c7 - *c9 + *c3 - *c1;

	    dxx = -(s4 + s5) / ((3. / 32.) * H * H);
	    dyy = -(s4 + s6) / ((3. / 32.) * V * V);
	    dxy = -s3 / ((1. / 16.) * H * V);

	    if (dxx_fd > 0) {
		if (out_type == CELL_TYPE)
		    *((CELL *) dxx_ptr) = (CELL) (scik1 * dxx);
		else
		    Rast_set_d_value(dxx_ptr, (DCELL) dxx, data_type);
		dxx_ptr = G_incr_void_ptr(dxx_ptr, Rast_cell_size(data_type));
	    }

	    if (dyy_fd > 0) {
		if (out_type == CELL_TYPE)
		    *((CELL *) dyy_ptr) = (CELL) (scik1 * dyy);
		else
		    Rast_set_d_value(dyy_ptr, (DCELL) dyy, data_type);
		dyy_ptr = G_incr_void_ptr(dyy_ptr, Rast_cell_size(data_type));
	    }

	    if (dxy_fd > 0) {
		if (out_type == CELL_TYPE)
		    *((CELL *) dxy_ptr) = (CELL) (scik1 * dxy);
		else
		    Rast_set_d_value(dxy_ptr, (DCELL) dxy, data_type);
		dxy_ptr = G_incr_void_ptr(dxy_ptr, Rast_cell_size(data_type));
	    }

	    /* compute curvature */
	    if (pcurv_fd <= 0 && tcurv_fd <= 0)
		continue;

	    grad2 = key;	/*dx2 + dy2 */
	    grad = sqrt(grad2);
	    if (grad <= gradmin) {
		pcurv = 0.;
		tcurv = 0.;
	    }
	    else {
		dnorm1 = sqrt(grad2 + 1.);
		dxy2 = 2. * dxy * dx * dy;
		dx2 = dx * dx;
		dy2 = dy * dy;
		pcurv = (dxx * dx2 + dxy2 + dyy * dy2) /
		    (grad2 * dnorm1 * dnorm1 * dnorm1);
		tcurv = (dxx * dy2 - dxy2 + dyy * dx2) / (grad2 * dnorm1);
		if (c1min > pcurv)
		    c1min = pcurv;
		if (c1max < pcurv)
		    c1max = pcurv;
		if (c2min > tcurv)
		    c2min = tcurv;
		if (c2max < tcurv)
		    c2max = tcurv;
	    }

	    if (pcurv_fd > 0) {
		if (out_type == CELL_TYPE)
		    *((CELL *) pcurv_ptr) = (CELL) (scik1 * pcurv);
		else
		    Rast_set_d_value(pcurv_ptr, (DCELL) pcurv, data_type);
		pcurv_ptr =
		    G_incr_void_ptr(pcurv_ptr, Rast_cell_size(data_type));
	    }

	    if (tcurv_fd > 0) {
		if (out_type == CELL_TYPE)
		    *((CELL *) tcurv_ptr) = (CELL) (scik1 * tcurv);
		else
		    Rast_set_d_value(tcurv_ptr, (DCELL) tcurv, data_type);
		tcurv_ptr =
		    G_incr_void_ptr(tcurv_ptr, Rast_cell_size(data_type));
	    }

	}			/* column for loop */

	if (aspect_fd > 0)
	    Rast_put_row(aspect_fd, asp_raster, data_type);

	if (slope_fd > 0)
	    Rast_put_row(slope_fd, slp_raster, data_type);

	if (pcurv_fd > 0)
	    Rast_put_row(pcurv_fd, pcurv_raster, data_type);

	if (tcurv_fd > 0)
	    Rast_put_row(tcurv_fd, tcurv_raster, data_type);

	if (dx_fd > 0)
	    Rast_put_row(dx_fd, dx_raster, data_type);

	if (dy_fd > 0)
	    Rast_put_row(dy_fd, dy_raster, data_type);

	if (dxx_fd > 0)
	    Rast_put_row(dxx_fd, dxx_raster, data_type);

	if (dyy_fd > 0)
	    Rast_put_row(dyy_fd, dyy_raster, data_type);

	if (dxy_fd > 0)
	    Rast_put_row(dxy_fd, dxy_raster, data_type);

    }				/* row loop */

    G_percent(row, nrows, 2);

    Rast_close(elevation_fd);
    G_debug(1, "Creating support files...");

    G_verbose_message(_("Elevation products for mapset <%s> in <%s>"),
		      G_mapset(), G_location());

    if (aspect_fd >= 0) {
	DCELL min, max;
	struct FPRange range;

	Rast_set_null_value(asp_raster, Rast_window_cols(), data_type);
	Rast_put_row(aspect_fd, asp_raster, data_type);
	Rast_close(aspect_fd);

	if (out_type != CELL_TYPE)
	    Rast_quantize_fp_map_range(aspect_name, G_mapset(), 0., 360., 0,
				    360);

	Rast_read_cats(aspect_name, G_mapset(), &cats);
	Rast_set_cats_title
	    ("Aspect counterclockwise in degrees from east", &cats);

	G_verbose_message(_("Min computed aspect %.4f, max computed aspect %.4f"),
			  min_asp, max_asp);
	/* the categries quant intervals are 1.0 long, plus
	   we are using reverse order so that the label looked up
	   for i-.5 is not the one defined for i-.5, i+.5 interval, but
	   the one defile for i-1.5, i-.5 interval which is added later */
	for (i = ceil(max_asp); i >= 1; i--) {
	    if (i == 360)
		sprintf(buf, "east");
	    else if (i == 360)
		sprintf(buf, "east");
	    else if (i == 45)
		sprintf(buf, "north ccw of east");
	    else if (i == 90)
		sprintf(buf, "north");
	    else if (i == 135)
		sprintf(buf, "north ccw of west");
	    else if (i == 180)
		sprintf(buf, "west");
	    else if (i == 225)
		sprintf(buf, "south ccw of west");
	    else if (i == 270)
		sprintf(buf, "south");
	    else if (i == 315)
		sprintf(buf, "south ccw of east");
	    else
		sprintf(buf, "%d degree%s ccw from east", i,
			i == 1 ? "" : "s");
	    if (data_type == CELL_TYPE) {
	      Rast_set_c_cat((CELL *) &i, (CELL *) &i, buf, &cats);
		continue;
	    }
	    tmp1 = (double)i - .5;
	    tmp2 = (double)i + .5;
	    Rast_set_d_cat(&tmp1, &tmp2, buf, &cats);
	}
	if (data_type == CELL_TYPE) {
	    cat = 0;
	    Rast_set_c_cat(&cat, &cat, "no aspect", &cats);
	}
	else {
	    tmp1 = 0.;
	    tmp2 = .5;
	    Rast_set_d_cat(&tmp1, &tmp2, "no aspect", &cats);
	}
	Rast_write_cats(aspect_name, &cats);
	Rast_free_cats(&cats);

	/* write colors for aspect file */
	Rast_init_colors(&colors);
	Rast_read_fp_range(aspect_name, G_mapset(), &range);
	Rast_get_fp_range_min_max(&range, &min, &max);
	Rast_make_aspect_fp_colors(&colors, min, max);
	Rast_write_colors(aspect_name, G_mapset(), &colors);

	/* writing history file */
	Rast_short_history(aspect_name, "raster", &hist);
	Rast_append_format_history(&hist, "aspect map elev = %s", elev_name);
	Rast_append_format_history(&hist, "zfactor = %.2f", zfactor);
	Rast_append_format_history(&hist, "min_slope = %f", min_slope);
	Rast_format_history(&hist, HIST_DATSRC_1, "raster elevation file %s", elev_name);
	Rast_command_history(&hist);
	Rast_write_history(aspect_name, &hist);

	G_message(_("Aspect raster map <%s> complete"), aspect_name);
    }

    if (slope_fd >= 0) {
	/* colortable for slopes */
	CELL val1, val2;
	Rast_init_colors(&colors);
	val1 = 0;
	val2 = 2;
	Rast_add_c_color_rule(&val1, 255, 255, 255, &val2, 255, 255, 0, &colors);
	val1 = 2;
	val2 = 5;
	Rast_add_c_color_rule(&val1, 255, 255, 0, &val2, 0, 255, 0, &colors);
	val1 = 5;
	val2 = 10;
	Rast_add_c_color_rule(&val1, 0, 255, 0, &val2, 0, 255, 255, &colors);
	val1 = 10;
	val2 = 15;
	Rast_add_c_color_rule(&val1, 0, 255, 255, &val2, 0, 0, 255, &colors);
	val1 = 15;
	val2 = 30;
	Rast_add_c_color_rule(&val1, 0, 0, 255, &val2, 255, 0, 255, &colors);
	val1 = 30;
	val2 = 50;
	Rast_add_c_color_rule(&val1, 255, 0, 255, &val2, 255, 0, 0, &colors);
	val1 = 50;
	val2 = 90;
	Rast_add_c_color_rule(&val1, 255, 0, 0, &val2, 0, 0, 0, &colors);
	
	Rast_set_null_value(slp_raster, Rast_window_cols(), data_type);
	Rast_put_row(slope_fd, slp_raster, data_type);
	Rast_close(slope_fd);

	if (out_type != CELL_TYPE) {
	    /* INCR_BY_ONE
	       if(deg)
	       Rast_quantize_fp_map_range(slope_name, G_mapset(), 0., 90., 1, 91);
	       else
	       Rast_quantize_fp_map_range(slope_name, G_mapset(), min_slp, max_slp, 
	       (CELL) min_slp + 1, (CELL) ceil(max_slp) + 1);
	     */
	    Rast_write_colors(slope_name, G_mapset(), &colors);
	    if (deg)
		Rast_quantize_fp_map_range(slope_name, G_mapset(), 0., 90., 0,
					90);
	    else		/* percent */
		Rast_quantize_fp_map_range(slope_name, G_mapset(), min_slp,
					max_slp, (CELL) min_slp,
					(CELL) ceil(max_slp));
	}

	Rast_read_cats(slope_name, G_mapset(), &cats);
	if (deg)
	    Rast_set_cats_title("slope in degrees", &cats);
	else if (perc)
	    Rast_set_cats_title("percent slope", &cats);

	G_verbose_message(_("Min computed slope %.4f, max computed slope %.4f"),
			  min_slp, max_slp);
	/* the categries quant intervals are 1.0 long, plus
	   we are using reverse order so that the label looked up
	   for i-.5 is not the one defined for i-.5, i+.5 interval, but
	   the one defined for i-1.5, i-.5 interval which is added later */
	for (i = ceil(max_slp); i > /* INC BY ONE >= */ 0; i--) {
	    if (deg)
		sprintf(buf, "%d degree%s", i, i == 1 ? "" : "s");
	    else if (perc)
		sprintf(buf, "%d percent", i);
	    if (data_type == CELL_TYPE) {
		/* INCR_BY_ONE
		   Rast_set_c_cat(i+1, buf, &cats);
		 */
		Rast_set_c_cat(&i, &i, buf, &cats);
		continue;
	    }
	    /* INCR_BY_ONE
	       tmp1 = (DCELL) i+.5;
	       tmp2 = (DCELL) i+1.5;
	     */
	    tmp1 = (DCELL) i - .5;
	    tmp2 = (DCELL) i + .5;
	    Rast_set_d_cat(&tmp1, &tmp2, buf, &cats);
	}
	if (data_type == CELL_TYPE) {
	    cat = 0;
	    Rast_set_c_cat(&cat, &cat, "zero slope", &cats);
	}
	/* INCR_BY_ONE
	   Rast_set_c_cat(0, "no data", &cats);
	 */
	else {
	    tmp1 = 0;
	    tmp2 = 0.5;
	    Rast_set_d_cat(&tmp1, &tmp2, "zero slope", &cats);
	}
	/* INCR_BY_ONE
	   Rast_set_d_cat (&tmp1, &tmp1, "no data", &cats);
	 */
	Rast_write_cats(slope_name, &cats);

	/* writing history file */
	Rast_short_history(slope_name, "raster", &hist);
	Rast_append_format_history(&hist, "slope map elev = %s", elev_name);
	Rast_append_format_history(&hist, "zfactor = %.2f format = %s", zfactor,
		parm.slope_fmt->answer);
	Rast_append_format_history(&hist, "min_slope = %f", min_slope);
	Rast_format_history(&hist, HIST_DATSRC_1, "raster elevation file %s", elev_name);
	Rast_command_history(&hist);
	Rast_write_history(slope_name, &hist);

	G_message(_("Slope raster map <%s> complete"), slope_name);
    }

    /* colortable for curvatures */
    if (pcurv_fd >= 0 || tcurv_fd >= 0) {
	Rast_init_colors(&colors);
	if (c1min < c2min)
	    dat1 = (FCELL) c1min;
	else
	    dat1 = (FCELL) c2min;

	dat2 = (FCELL) - 0.01;
	Rast_add_f_color_rule(&dat1, 127, 0, 255,
				  &dat2, 0, 0, 255, &colors);
	dat1 = dat2;
	dat2 = (FCELL) - 0.001;
	Rast_add_f_color_rule(&dat1, 0, 0, 255,
				  &dat2, 0, 127, 255, &colors);
	dat1 = dat2;
	dat2 = (FCELL) - 0.00001;
	Rast_add_f_color_rule(&dat1, 0, 127, 255,
				  &dat2, 0, 255, 255, &colors);
	dat1 = dat2;
	dat2 = (FCELL) 0.0;
	Rast_add_f_color_rule(&dat1, 0, 255, 255,
				  &dat2, 200, 255, 200, &colors);
	dat1 = dat2;
	dat2 = (FCELL) 0.00001;
	Rast_add_f_color_rule(&dat1, 200, 255, 200,
				  &dat2, 255, 255, 0, &colors);
	dat1 = dat2;
	dat2 = (FCELL) 0.001;
	Rast_add_f_color_rule(&dat1, 255, 255, 0,
				  &dat2, 255, 127, 0, &colors);
	dat1 = dat2;
	dat2 = (FCELL) 0.01;
	Rast_add_f_color_rule(&dat1, 255, 127, 0,
				  &dat2, 255, 0, 0, &colors);
	dat1 = dat2;
	if (c1max > c2max)
	    dat2 = (FCELL) c1max;
	else
	    dat2 = (FCELL) c2max;

	Rast_add_f_color_rule(&dat1, 255, 0, 0,
				  &dat2, 255, 0, 200, &colors);
    }

    if (pcurv_fd >= 0) {
	Rast_set_null_value(pcurv_raster, Rast_window_cols(), data_type);
	Rast_put_row(pcurv_fd, pcurv_raster, data_type);
	Rast_close(pcurv_fd);

	Rast_write_colors(pcurv_name, G_mapset(), &colors);

	if (out_type != CELL_TYPE)
	    Rast_round_fp_map(pcurv_name, G_mapset());

	Rast_read_cats(pcurv_name, G_mapset(), &cats);
	Rast_set_cats_title("profile curvature", &cats);
	cat = 0;
	Rast_set_c_cat(&cat, &cat, "no profile curve", &cats);

	/* writing history file */
	Rast_short_history(pcurv_name, "raster", &hist);
	Rast_append_format_history(&hist, "profile curve map elev = %s", elev_name);
	Rast_append_format_history(&hist, "zfactor = %.2f", zfactor);
	Rast_append_format_history(&hist, "min_slope = %f", min_slope);
	Rast_format_history(&hist, HIST_DATSRC_1, "raster elevation file %s", elev_name);
	Rast_command_history(&hist);
	Rast_write_history(pcurv_name, &hist);

	G_message(_("Profile curve raster map <%s> complete"), pcurv_name);
    }

    if (tcurv_fd >= 0) {
	Rast_set_null_value(tcurv_raster, Rast_window_cols(), data_type);
	Rast_put_row(tcurv_fd, tcurv_raster, data_type);
	Rast_close(tcurv_fd);

	Rast_write_colors(tcurv_name, G_mapset(), &colors);

	if (out_type != CELL_TYPE)
	    Rast_round_fp_map(tcurv_name, G_mapset());

	Rast_read_cats(tcurv_name, G_mapset(), &cats);
	Rast_set_cats_title("tangential curvature", &cats);
	cat = 0;
	Rast_set_c_cat(&cat, &cat, "no tangential curve", &cats);

	/* writing history file */
	Rast_short_history(tcurv_name, "raster", &hist);
	Rast_append_format_history(&hist, "tangential curve map elev = %s", elev_name);
	Rast_append_format_history(&hist, "zfactor = %.2f", zfactor);
	Rast_append_format_history(&hist, "min_slope = %f", min_slope);
	Rast_format_history(&hist, HIST_DATSRC_1, "raster elevation file %s", elev_name);
	Rast_command_history(&hist);
	Rast_write_history(tcurv_name, &hist);

	G_message(_("Tangential curve raster map <%s> complete"), tcurv_name);
    }

    if (dx_fd >= 0) {
	Rast_set_null_value(dx_raster, Rast_window_cols(), data_type);
	Rast_put_row(dx_fd, dx_raster, data_type);
	Rast_close(dx_fd);

	if (out_type != CELL_TYPE)
	    Rast_round_fp_map(dx_name, G_mapset());

	Rast_read_cats(dx_name, G_mapset(), &cats);
	Rast_set_cats_title("E-W slope", &cats);
	cat = 0;	
	Rast_set_c_cat(&cat, &cat, "no E-W slope", &cats);

	/* writing history file */
	Rast_short_history(dx_name, "raster", &hist);
	Rast_append_format_history(&hist, "E-W slope map elev = %s", elev_name);
	Rast_append_format_history(&hist, "zfactor = %.2f", zfactor);
	Rast_append_format_history(&hist, "min_slope = %f", min_slope);
	Rast_format_history(&hist, HIST_DATSRC_1, "raster elevation file %s", elev_name);
	Rast_command_history(&hist);
	Rast_write_history(dx_name, &hist);

	G_message(_("E-W slope raster map <%s> complete"), dx_name);
    }

    if (dy_fd >= 0) {
	Rast_set_null_value(dy_raster, Rast_window_cols(), data_type);
	Rast_put_row(dy_fd, dy_raster, data_type);
	Rast_close(dy_fd);

	if (out_type != CELL_TYPE)
	    Rast_round_fp_map(dy_name, G_mapset());

	Rast_read_cats(dy_name, G_mapset(), &cats);
	Rast_set_cats_title("N-S slope", &cats);
	cat = 0;
	Rast_set_c_cat(&cat, &cat, "no N-S slope", &cats);

	/* writing history file */
	Rast_short_history(dy_name, "raster", &hist);
	Rast_append_format_history(&hist, "N-S slope map elev = %s", elev_name);
	Rast_append_format_history(&hist, "zfactor = %.2f", zfactor);
	Rast_append_format_history(&hist, "min_slope = %f", min_slope);
	Rast_format_history(&hist, HIST_DATSRC_1, "raster elevation file %s", elev_name);
	Rast_command_history(&hist);
	Rast_write_history(dy_name, &hist);

	G_message(_("N-S slope raster map <%s> complete"), dy_name);
    }

    if (dxx_fd >= 0) {
	Rast_set_null_value(dxx_raster, Rast_window_cols(), data_type);
	Rast_put_row(dxx_fd, dxx_raster, data_type);
	Rast_close(dxx_fd);

	if (out_type != CELL_TYPE)
	    Rast_round_fp_map(dxx_name, G_mapset());

	Rast_read_cats(dxx_name, G_mapset(), &cats);
	Rast_set_cats_title("DXX", &cats);
	cat = 0;
	Rast_set_c_cat(&cat, &cat, "DXX", &cats);

	/* writing history file */
	Rast_short_history(dxx_name, "raster", &hist);
	Rast_append_format_history(&hist, "DXX map elev = %s", elev_name);
	Rast_append_format_history(&hist, "zfactor = %.2f", zfactor);
	Rast_append_format_history(&hist, "min_slope = %f", min_slope);
	Rast_format_history(&hist, HIST_DATSRC_1, "raster elevation file %s", elev_name);
	Rast_command_history(&hist);
	Rast_write_history(dxx_name, &hist);

	G_message(_("Dxx raster map <%s> complete"), dxx_name);
    }

    if (dyy_fd >= 0) {
	Rast_set_null_value(dyy_raster, Rast_window_cols(), data_type);
	Rast_put_row(dyy_fd, dyy_raster, data_type);
	Rast_close(dyy_fd);

	if (out_type != CELL_TYPE)
	    Rast_round_fp_map(dyy_name, G_mapset());

	Rast_read_cats(dyy_name, G_mapset(), &cats);
	Rast_set_cats_title("DYY", &cats);
	cat = 0;
	Rast_set_c_cat(&cat, &cat, "DYY", &cats);

	/* writing history file */
	Rast_short_history(dyy_name, "raster", &hist);
	Rast_append_format_history(&hist, "DYY map elev = %s", elev_name);
	Rast_append_format_history(&hist, "zfactor = %.2f", zfactor);
	Rast_append_format_history(&hist, "min_slope = %f", min_slope);
	Rast_format_history(&hist, HIST_DATSRC_1, "raster elevation file %s", elev_name);
	Rast_command_history(&hist);
	Rast_write_history(dyy_name, &hist);

	G_message(_("Dyy raster map <%s> complete"), dyy_name);
    }

    if (dxy_fd >= 0) {
	Rast_set_null_value(dxy_raster, Rast_window_cols(), data_type);
	Rast_put_row(dxy_fd, dxy_raster, data_type);
	Rast_close(dxy_fd);

	if (out_type != CELL_TYPE)
	    Rast_round_fp_map(dxy_name, G_mapset());

	Rast_read_cats(dxy_name, G_mapset(), &cats);
	Rast_set_cats_title("DXY", &cats);
	cat = 0;
	Rast_set_c_cat(&cat, &cat, "DXY", &cats);

	/* writing history file */
	Rast_short_history(dxy_name, "raster", &hist);
	Rast_append_format_history(&hist, "DXY map elev = %s", elev_name);
	Rast_append_format_history(&hist, "zfactor = %.2f", zfactor);
	Rast_append_format_history(&hist, "min_slope = %f", min_slope);
	Rast_format_history(&hist, HIST_DATSRC_1, "raster elevation file %s", elev_name);
	Rast_command_history(&hist);
	Rast_write_history(dxy_name, &hist);

	G_message(_("Dxy raster map <%s> complete"), dxy_name);
    }

    exit(EXIT_SUCCESS);
}