pair<double, double> polygon_gravity_center(node *s, int n)
{//多边形s有n个顶点，下标从0到n-1，顶点按逆时针方向排列
//返回多边形重心，pair.first是x坐标，pair.second是y坐标
node p(0, 0);
//数组o指代三角形重心，数组area指代三角形面积
pair<double, double> o[MAX];
double area[MAX];
for(int i = 0; i < n; ++ i){
if(i != n - 1){
o[i] = triangle_gravity_center(p, s[i], s[i + 1]);
area[i] = triangle_area(p, s[i], s[i + 1]);
}
else{
o[i] = triangle_gravity_center(p, s[i], s[0]);
area[i] = triangle_area(p, s[i], s[0]);
}
}
double a_sum(0);
pair<double, double> o_sum(0, 0);
for(int i = 0; i < n; ++ i)
a_sum += area[i];
for(int i = 0; i < n; ++ i){
o_sum.first += o[i].first * area[i];
o_sum.second += o[i].second * area[i];
}
return(make_pair(o_sum.first / a_sum, o_sum.second / a_sum));
}
int main(int argc, char **argv)
{
char *mapset;
int o_method;
struct GModule *module;
struct Option *method, *basemap, *covermap, *outputmap;
struct Flag *flag_c;
struct Categories cats;
char methods[1024];
G_gisinit(argv[0]);
module = G_define_module();
module->keywords = _("raster, statistics");
module->description =
_("Calculates category or object oriented statistics.");
basemap = G_define_standard_option(G_OPT_R_BASE);
covermap = G_define_standard_option(G_OPT_R_COVER);
for (o_method = 0; menu[o_method].name; o_method++) {
if (o_method)
strcat(methods, ",");
else
*(methods) = 0;
strcat(methods, menu[o_method].name);
}
method = G_define_option();
method->key = "method";
method->type = TYPE_STRING;
method->required = YES;
method->description = _("Method of object-based statistic");
method->options = methods;
outputmap = G_define_standard_option(G_OPT_R_OUTPUT);
outputmap->description =
_("Resultant raster map (not used with 'distribution')");
outputmap->required = NO;
flag_c = G_define_flag();
flag_c->key = 'c';
flag_c->description =
_("Cover values extracted from the category labels of the cover map");
if (G_parser(argc, argv))
exit(EXIT_FAILURE);
if ((mapset = G_find_cell2(basemap->answer, "")) == 0)
G_fatal_error(_("Raster map <%s> not found"), basemap->answer);
if (G_raster_map_is_fp(basemap->answer, mapset) != 0)
G_fatal_error(_("This module currently only works for integer (CELL) maps"));
if ((mapset = G_find_cell2(covermap->answer, "")) == 0)
G_fatal_error(_("Raster map <%s> not found"), covermap->answer);
if (G_raster_map_is_fp(covermap->answer, mapset) != 0)
G_fatal_error(_("This module currently only works for integer (CELL) maps"));
if (G_read_cats(covermap->answer, mapset, &cats) < 0) {
G_fatal_error(_("Unable to read category file of raster map <%s@%s>"),
covermap->answer, mapset);
}
for (o_method = 0; menu[o_method].name; o_method++)
if (strcmp(menu[o_method].name, method->answer) == 0)
break;
if (!menu[o_method].name) {
G_warning(_("<%s=%s> unknown %s"), method->key, method->answer,
method->key);
G_usage();
exit(EXIT_FAILURE);
}
switch (menu[o_method].val) {
case DISTRIB:
if (outputmap->answer != NULL)
G_warning(_("Output map <%s> ignored"), outputmap->answer);
o_distrib(basemap->answer, covermap->answer,
outputmap->answer, flag_c->answer);
break;
case AVERAGE:
is_ok(method->answer, outputmap->answer);
o_average(basemap->answer, covermap->answer,
outputmap->answer, flag_c->answer, &cats);
break;
case MODE:
is_ok(method->answer, outputmap->answer);
o_mode(basemap->answer, covermap->answer,
outputmap->answer, flag_c->answer, &cats);
break;
case ADEV:
is_ok(method->answer, outputmap->answer);
o_adev(basemap->answer, covermap->answer,
outputmap->answer, flag_c->answer, &cats);
break;
case SDEV:
is_ok(method->answer, outputmap->answer);
o_sdev(basemap->answer, covermap->answer,
outputmap->answer, flag_c->answer, &cats);
break;
case VARIANC:
is_ok(method->answer, outputmap->answer);
o_var(basemap->answer, covermap->answer,
outputmap->answer, flag_c->answer, &cats);
break;
case SKEWNES:
is_ok(method->answer, outputmap->answer);
o_skew(basemap->answer, covermap->answer,
outputmap->answer, flag_c->answer, &cats);
break;
case KURTOSI:
is_ok(method->answer, outputmap->answer);
o_kurt(basemap->answer, covermap->answer,
outputmap->answer, flag_c->answer, &cats);
break;
case MEDIAN:
is_ok(method->answer, outputmap->answer);
o_median(basemap->answer, covermap->answer,
outputmap->answer, flag_c->answer, &cats);
break;
case MIN:
is_ok(method->answer, outputmap->answer);
o_min(basemap->answer, covermap->answer,
outputmap->answer, flag_c->answer, &cats);
break;
case MAX:
is_ok(method->answer, outputmap->answer);
o_max(basemap->answer, covermap->answer,
outputmap->answer, flag_c->answer, &cats);
break;
case SUM:
is_ok(method->answer, outputmap->answer);
o_sum(basemap->answer, covermap->answer,
outputmap->answer, flag_c->answer, &cats);
break;
case DIV:
is_ok(method->answer, outputmap->answer);
o_divr(basemap->answer, covermap->answer,
outputmap->answer, flag_c->answer, &cats);
break;
default:
G_fatal_error(_("Not yet implemented!"));
}
return 0;
}