/* * $Id: c_cssex01.c,v 1.7 2000/01/12 23:50:55 fred Exp $ */ #include #include /* * Function prototypes for ngmath functions. */ #include /* * Function prototype for the function that draws label boxes. */ void c_draw_box(float, float, float, float, int); /* * Function prototypes for NCARG and NCARG-GKS routines */ #include #include #define IWTYPE 1 #define WKID 1 /* * Number of input data coordinates. */ #define N 7 /* * Number of points to be used in drawing arcs. */ #define NARC 50 main() { int i, j, k, np, ns, indx; Gcolr_rep rgb; float plat[2*N], plon[2*N], rc[2*N]; float rlat1, rlon1, rlat2, rlon2, pnm, rcd; int numv=0, nca, nv[2*N]; /* * Example of Delaunay triangulation and Voronoi diagram * on the surface of a sphere. */ /* * Input dataset on the globe (latitudes and longitudes in degrees). * These data points do not cover the globe, but rather are confined * to the nothern hemisphere and are enclosed by a boundary. */ float rlat[N] = { 70., 70., 70., 85., 60., 60., 65.}; float rlon[N] = {-160., -70., 0., 20., 50., 80.,140.}; /* * Declare the arrays for holding the points for drawing * circular arcs. */ float arclat[NARC], arclon[NARC]; /* * Pointer to array of triangle indices; number of triangles; error value. */ int *ltri, nt, ier; /* * c_supmap arguments. */ float plm1[2] = {0., 0.}; float plm2[2] = {0., 0.}; float plm3[2] = {0., 0.}; float plm4[2] = {0., 0.}; /* * Create the triangulation. */ ltri = c_csstri(N, rlat, rlon, &nt, &ier); /* * Get the circumcenters of the Delaunay triangles. */ c_csvoro(N, rlat, rlon, 0, 1, plat, plon, rc, &nca, &numv, nv, &ier); /* * Plot the Delaunay triangulation, the circumcircles, and * the Voronoi polygons on a sphere. * */ /* * Open GKS, open and actibvate a workstation. */ gopen_gks ("stdout",0); gopen_ws (WKID, NULL, IWTYPE); gactivate_ws(WKID); /* * Color table. */ rgb.rgb.red = 0.; rgb.rgb.green = 0.; rgb.rgb.blue = 0.; gset_colr_rep(WKID,0,&rgb); rgb.rgb.red = 1.; rgb.rgb.green = 1.; rgb.rgb.blue = 1.; gset_colr_rep(WKID,1,&rgb); rgb.rgb.red = 0.; rgb.rgb.green = 1.; rgb.rgb.blue = 1.; gset_colr_rep(WKID,2,&rgb); rgb.rgb.red = 1.; rgb.rgb.green = 1.; rgb.rgb.blue = 0.; gset_colr_rep(WKID,3,&rgb); rgb.rgb.red = 1.; rgb.rgb.green = 0.; rgb.rgb.blue = 0.; gset_colr_rep(WKID,4,&rgb); rgb.rgb.red = 0.; rgb.rgb.green = 1.; rgb.rgb.blue = 0.; gset_colr_rep(WKID,5,&rgb); rgb.rgb.red = 0.; rgb.rgb.green = .8; rgb.rgb.blue = 0.; gset_colr_rep(WKID,6,&rgb); /* * Draw a map of the North Atlantic, as seen by a satellite. */ gset_line_colr_ind(6); c_mapstr ("SA", 4.); c_mappos (0.175, 0.975, 0.025, 0.825); c_supmap (7, 72.5, 127.5, 0., plm1, plm2, plm3, plm4, 1, -1000, 5, 0, &ier); /* * Plot the circumcircles whose circumcenters lie in one of * the Delaunay triangles composed of original data points * (exclude the pseudo points added to complete the * triangulation on the whole sphere). */ gset_linewidth(2.0); gset_line_colr_ind(4); for (i = 4; i < nca; i++) { rlat2 = plat[i]; rlon2 = plon[i]; rcd = rc[i]; c_nggcog(rlat2, rlon2, rcd, arclat, arclon, NARC); c_mapit (arclat[0], arclon[0], 0); for (k = 1; k < NARC-1; k++) { c_mapit (arclat[k], arclon[k], 1); } c_mapit (arclat[NARC-1], arclon[NARC-1], 1); c_mapiq(); } /* * Draw the Voronoi polygons (note that c_csvcoro has already * been called once above with no intervening call that would * change the work arrays). */ for (i = 0; i < N; i++) { c_csvoro(N, rlat, rlon, i, 0, plat, plon, rc, &nca, &numv, nv, &ier); for (j = 1; j < numv; j++) { rlat1 = plat[nv[j-1]]; rlon1 = plon[nv[j-1]]; rlat2 = plat[nv[j]]; rlon2 = plon[nv[j]]; gset_line_colr_ind(3); c_mapgci(rlat1, rlon1, rlat2, rlon2, NARC, arclat, arclon); c_mapit (rlat1, rlon1, 0); for (k = 0; k < NARC; k++) { c_mapit (arclat[k], arclon[k], 1); } c_mapit (rlat2, rlon2, 1); c_mapiq(); } } /* * Draw the Delaunay triangles. */ gset_linewidth(2.0); gset_line_colr_ind(2); for (np = 0; np < nt; np++) { indx = 3*np; for (ns = 0; ns < 3; ns++) { c_mapgci(rlat[ltri[indx+ns]], rlon[ltri[indx+ns]], rlat[ltri[indx+(ns+1)%3]], rlon[ltri[indx+(ns+1)%3]], NARC, arclat, arclon); c_mapit (rlat[ltri[indx+ns]], rlon[ltri[indx+ns]], 0); for (i = 0; i < NARC; i++) { c_mapit (arclat[i], arclon[i], 1); } c_mapit (rlat[ltri[indx+(ns+1)%3]], rlon[ltri[indx+(ns+1)%3]], 1); c_mapiq(); } } /* * Mark the original data points (create a circular * marker by drawing five concentric circles). */ gset_line_colr_ind(3); for (k = 1; k < 6; k++) { for (i = 0; i < N; i++) { c_nggcog (rlat[i], rlon[i], 0.2 * (float) k, arclat, arclon, NARC); c_mapit (arclat[0], arclon[0], 0); for (j = 1; j < NARC-1; j++) { c_mapit (arclat[j], arclon[j], 1); } c_mapit (arclat[NARC-1], arclon[NARC-1], 1); c_mapiq(); } } /* * Mark the circumcircle centers. */ gset_line_colr_ind(5); for (k = 0; k < 5; k++) { for (i = 4; i < 10; i++) { rlat1 = plat[i]; rlon1 = plon[i]; c_nggcog (rlat1, rlon1, 0.1 * (float) k, arclat, arclon, NARC); c_mapit (arclat[0], arclon[0], 0); for (j = 1; j < NARC-1; j++) { c_mapit (arclat[j], arclon[j], 1); } c_mapit (arclat[NARC-1], arclon[NARC-1], 1); c_mapiq(); } } /* * Legend. */ c_set(0.,1.,0.,1.,0.,1.,0.,1.,1); c_draw_box(0.02, 0.945, 0.12, 0.955, 2); c_pcseti("CC",1); c_plchhq(0.14,0.95,":F22:Delaunay triangles",.025,0.,-1.0); c_draw_box(0.02, 0.895, 0.12, 0.905, 3); c_plchhq(0.14,0.90,":F22:Voronoi polygons",.025,0.,-1.0); c_draw_box(0.02, 0.845, 0.12, 0.855, 4); c_plchhq(0.14,0.85,":F22:Circumcircles",.025,0.,-1.0); c_frame(); gdeactivate_ws (WKID); gclose_ws (WKID); gclose_gks(); } /* * Draw a color-filled box specified by two corner points and * a color index.. */ void c_draw_box(float xll, float yll, float xur, float yur, int cindex) { Gpoint vbox[5]; Gpoint_list pl; vbox[0].x = xll; vbox[0].y = yll; vbox[1].x = xur; vbox[1].y = yll; vbox[2].x = xur; vbox[2].y = yur; vbox[3].x = xll; vbox[3].y = yur; vbox[4].x = xll; vbox[4].y = yll; pl.num_points = 5; pl.points = vbox; gset_fill_colr_ind(cindex); gfill_area(&pl); }