int lookup_and_function_ptrs(SHORT nrows, SHORT ncols)
{
double a, e2; /* used to control geodetic distance calculations */
if ((ll = (G_projection() == PROJECTION_LL))) {
/* equivalent to G_begin_distance_calculations () */
G_get_ellipsoid_parameters(&a, &e2);
G_begin_geodesic_distance_l(nrows, a, e2);
LL_lookup_tables(nrows, ncols);
init_row_search = first_west_LL;
comp_row_search = completed_row_LL;
locate_neighbors = find_neighbors_LL;
check_offset = offset_distance_LL;
exhaust_row = exhaust_search_LL;
}
else {
lookup_tables(nrows, ncols);
init_row_search = first_west;
comp_row_search = completed_row;
locate_neighbors = find_neighbors;
check_offset = offset_distance;
exhaust_row = exhaust_search;
}
return 0;
}
/*!
\brief Get ellipsoid name for the current location
\return pointer to valid name if ok
\return NULL on error
*/
const char *G_database_ellipse_name(void)
{
const char *name;
name = lookup_proj("ellps");
if (!name) {
char buf[256];
double a, es;
G_get_ellipsoid_parameters(&a, &es);
sprintf(buf, "a=%.16g es=%.16g", a, es);
name = G_store(buf);
}
/* strcpy (name, "Unknown ellipsoid"); */
return name;
}
void plot(double lon1, double lat1, double lon2, double lat2,
int line_color, int text_color, double factor, const char *unit)
{
double distance;
double text_x, text_y;
double a, e2;
int nsteps = 1000;
int i;
/* establish the current graphics window */
D_setup(0);
G_get_ellipsoid_parameters(&a, &e2);
G_begin_geodesic_distance(a, e2);
D_use_color(line_color);
G_shortest_way(&lon1, &lon2);
if (lon1 != lon2) {
G_begin_geodesic_equation(lon1, lat1, lon2, lat2);
D_begin();
for (i = 0; i <= nsteps; i++) {
double lon = lon1 + (lon2 - lon1) * i / nsteps;
double lat = G_geodesic_lat_from_lon(lon);
if (i == 0)
D_move_abs(lon, lat);
else
D_cont_abs(lon, lat);
}
D_end();
D_stroke();
text_x = (lon1 + lon2) / 2;
text_y = G_geodesic_lat_from_lon(text_x);
}
else {
D_line_abs(lon1, lat1, lon2, lat2);
text_x = (lon1 + lon2) / 2;
text_y = (lat1 + lat2) / 2;
}
if (text_color != -1) {
double t, b, l, r;
char buf[100];
D_text_size(10, 10);
distance = G_geodesic_distance(lon1, lat1, lon2, lat2);
sprintf(buf, "%.0f %s", distance / factor, unit);
D_pos_abs(text_x, text_y);
D_get_text_box(buf, &t, &b, &l, &r);
if (t - D_get_u_north() > 0)
text_y -= t - D_get_u_north();
if (b - D_get_u_south() < 0)
text_y -= b - D_get_u_south();
if (r - D_get_u_east() > 0)
text_x -= r - D_get_u_east();
if (l - D_get_u_west() < 0)
text_x -= l - D_get_u_west();
D_use_color(text_color);
D_pos_abs(text_x, text_y);
D_text(buf);
}
}