Function gmtinit_parse_proj4

src/gmt_init.c:18272–18430

}

GMT_LOCAL int gmtinit_parse_proj4(struct GMT_CTRL *GMT, char *item, char *dest) {
	/* Deal with proj.4 or EPSGs passed in -J option */
	char  *item_t1 = NULL, *item_t2 = NULL, epsg2proj[GMT_LEN256] = {""}, wktext[32] = {""}, *pch;
	bool   do_free = false;
	int    error = 0, scale_pos;
	size_t k, len;
	double sc;

	if (item[0] == '+') {
		bool found = false;
		len = strlen(item);
		for (k = 1; k < len; k++) {			/* Search for glued tokens */
			if (item[k] == '+' && item[k-1] != ' ') {
				found = true;
				break;
			}
		}
		if (found) {			/* OK, need to break up things like +x=0+y=0 into "+x=0 +y=0" */
			item_t1 = gmt_strrep(item, "+", " +");
			do_free = true;		/* Signal that we must free item_t1 */
		}
		else
			item_t1 = item;

		snprintf(GMT->common.J.proj4string, GMT_LEN256, "%s", item_t1);		/* Copy the proj.4 string */
	}
	else if (!strncmp(item, "EPSG:", 5) || !strncmp(item, "epsg:", 5))
		item_t1 = &item[5];		/* Drop the EPSG: part because gmt_impotproj4 is not expecting it */
	else
		item_t1 = item;

	item_t2 = gmt_importproj4(GMT, item_t1, &scale_pos, epsg2proj);		/* This is the GMT -J proj string */
	if (item_t2 && !GMT->current.ps.active && !strcmp(item_t2, "/1:1")) {
		/* Even though it failed to do the mapping we can still use it in mapproject */
		GMT->current.proj.projection_GMT = GMT_NO_PROJ;
		GMT->current.proj.is_proj4 = true;
		GMT->current.proj.pars[14] = 1;
	}
	else if (item_t2) {
		char *pch2;
		len = strlen(item_t2);
		if (item_t2[len-1] == 'W') {				/* See if scale is in fact a width */
			item_t2[0] = (char)toupper(item_t2[0]);		/* and let the GMT machinery detect this fact */
			item_t2[len-1] = '\0';
		}
		if (scale_pos != 0) {	/* Because if == 0 than it means we have a scale only string (i.e. no GMT mapped proj) */
			error += (gmt_M_check_condition(GMT, GMT->common.J.active, "Option -J given more than once\n") ||
			                                gmtinit_parse_J_option (GMT, item_t2));
		}
		else		/* Not particularly useful yet because mapproject will fail anyway when scale != 1:1 */
			GMT->current.proj.projection_GMT = GMT_NO_PROJ;

		/* If input was a EPSG code, save the epsg -> proj conversion string. Save also if input was a +proj string */
		if (epsg2proj[0] != '\0')   snprintf(GMT->common.J.proj4string, GMT_LEN256-1, "%s", epsg2proj);
		else if (item_t1[0] == '+') snprintf(GMT->common.J.proj4string, GMT_LEN256-1, "%s", item_t1);

		/* Check if the scale is 1 or 1:1, and don't get fooled with, for example, 1:10 */
		pch = &item_t2[scale_pos];