Function gmt_parse_segmentize

src/gmt_init.c:10179–10245

! . */

/*! . */
unsigned int gmt_parse_segmentize (struct GMT_CTRL *GMT, char option, char *in_arg, unsigned int mode, struct GMT_SEGMENTIZE *S) {
	/* Parse segmentizing options in gmt convert (mode == 0) or psxy (mode == 1).
	 * Syntax is given below (assuming option = -F here):
	 * -F<scheme><method: i.e., -F[c|n|p[<origin>|v][a|r|s|t] or -Fp<origin>
	 * where <scheme> is c = continuous [Default], n = network, r = reference point, and v = vectors.
	 * and impact is a = all tables, t = per table, s = per segment [Default], r = per record.
	 * Four different segmentizing schemes:
	 * 1) -Fc: Continuous lines.  By default, lines are drawn on a segment by segment basis.
	 *    Thus, -F or -Fc or -Fcs or -Fs is the standard default.  However, if we use
	 *    -Fcf or -Ff then we ignore segment headers WITHIN each file, except for the first header
	 *   in each file.  In other words, all points in a file will be considered continuous.
	 *   Finally, using -Fca or -Fa then all points in all fields are considered continuous and
	 *   only the first segment header in the first file is considered.  So only a|f|r is allowed.
	 * 2) -Fn: Network.  For each group of points we connect each point with every other point.
	 *   The modifiers a,f,s control what the "group" is.  With s, we construct a separate
	 *   network for each segment, with f we group all segments in a file and construct a
	 *   network for all those points, while with a with consider all points in the dataset
	 *   to be one group. So only a|t|s is allowed.
	 * 3) -Fp: Ref point.  Here, we construct line segments from the given reference point to
	 *   each of the points in the file.  If refpoint is given as two slash-separated coordinates
	 *   then the refpoint is fixed throughout this construction.  However, refpoint may also be
	 *   given as a, f, s and if so we pick the first point in the dataset, or first point in each
	 *   file, or the first point in each segment to update the actual reference point.
	 * 4) -Fv: Vectorize.  Here, consecutive points are turned into vector segments such as used
	 *   by gmt plot -Sv+s or external applications.  Again, appending a|s|t controls if we should
	 *   honor the segment headers [Default is -Fvs if -Fv is given]. Only a|t|s is allowed in plot.
	 */

	unsigned int k, errors = 0;
	switch (in_arg[0]) {	/* First set method */
		case 'c': k = 1;	S->method  = SEGM_CONTINUOUS;	break;
		case 'n': k = 1;	S->method  = SEGM_NETWORK;	break;
		case 'p': case 'r': k = 1;	S->method  = SEGM_REFPOINT;	break;	/* Backwards support for r for refpoint, now p for point */
		case 'v': k = 1;	S->method  = SEGM_VECTOR;	break;
		default:  k = 0;	S->method  = SEGM_CONTINUOUS;	break;
	}

	switch (in_arg[k]) {	/* Now set level */
		case 's': case '\0': S->level = SEGM_SEGMENT;	break;	/* Default is segment */
		case 'a': S->level = SEGM_DATASET;	break;
		case 't': case 'f': S->level = SEGM_TABLE;	break;	/* Backwards compatibility for f(ile) */
		case 'r': S->level = SEGM_RECORD;	break;
		default:	/* Must be a reference point but only if method is refpoint */
			if (S->method == SEGM_REFPOINT && strchr (in_arg, '/')) {	/* Gave arguments for an origin */
				S->level = SEGM_ORIGIN;
				if ((k = gmt_get_pair (GMT, &in_arg[k], GMT_PAIR_COORD, S->origin)) < 2) errors++;
			}
			else {
				GMT_Report (GMT->parent, GMT_MSG_ERROR, "Option -%c: Expected reference point coordinates but got this: %s\n", option, &in_arg[k]);
				errors++;
			}
			break;
	}
	if (S->method == SEGM_CONTINUOUS && S->level == SEGM_SEGMENT) {
		GMT_Report (GMT->parent, GMT_MSG_ERROR, "Option -%c: Selecting -Fc, -Fs, or -Fcs yields no change\n", option);
		errors++;
	}
	if (S->method != SEGM_REFPOINT && S->level == SEGM_RECORD) {