diff --git a/src/gmt_init.c b/src/gmt_init.c
index 3484d3ac1b2..aaf66cb25fe 100644
--- a/src/gmt_init.c
+++ b/src/gmt_init.c
@@ -16456,6 +16456,7 @@ void gmt_detect_oblique_region (struct GMT_CTRL *GMT, char *file) {
 	if (!GMT->common.R.active[RSET]) return;	/* No -R given, presumably use whole grid or image */
 	if (!(gmt_M_360_range (GMT->common.R.wesn[XLO], GMT->common.R.wesn[XHI]) && gmt_M_180_range (GMT->common.R.wesn[YLO], GMT->common.R.wesn[YHI]))) return;	/* Gave -Rd or -Rg so need to probe more*/
 	if (gmt_M_is_azimuthal (GMT) && doubleAlmostEqual (fabs (GMT->current.proj.lat0), 90.0) && !GMT->common.R.oblique) return;	/* Nothing to do */
+	if (GMT->current.proj.projection == GMT_PROJ4_SPILHAUS) return;		/* This is one is square */
 	gmt_M_memcpy (wesn, GMT->common.R.wesn, 4, double);	/* Save the region we were given */
 
  	if (gmt_map_setup (GMT, GMT->common.R.wesn))	/* Set up projection */
@@ -18544,12 +18545,14 @@ int gmt_parse_common_options (struct GMT_CTRL *GMT, char *list, char option, cha
 				}
 				if (GMT->current.gdal_read_in.hCT_fwd) OCTDestroyCoordinateTransformation(GMT->current.gdal_read_in.hCT_fwd);
 				if (GMT->current.gdal_read_in.hCT_inv) OCTDestroyCoordinateTransformation(GMT->current.gdal_read_in.hCT_inv);
-				GMT->current.gdal_read_in.hCT_fwd = gmt_OGRCoordinateTransformation (GMT, source, dest);
-				GMT->current.gdal_read_in.hCT_inv = gmt_OGRCoordinateTransformation (GMT, dest, source);
+				GMT->current.gdal_read_in.hCT_fwd = gmt_OGRCoordinateTransformation(GMT, source, dest);
+				GMT->current.gdal_read_in.hCT_inv = gmt_OGRCoordinateTransformation(GMT, dest, source);
 				GMT->current.proj.projection = strstr(dest, "spilhaus") ? GMT_PROJ4_SPILHAUS : GMT_PROJ4_PROJS;	/* Special case for spilhaus */
 				GMT->common.J.active = true;
 				if (GMT->current.gdal_read_in.hCT_fwd == NULL || GMT->current.gdal_read_in.hCT_inv == NULL)
 					error = 1;
+				else if (error && strstr(dest, "+proj="))	/* In this case it arrived here with error = 1 */
+					error = 0;
 			}
 			else {	/* Horizontal map projection */
 				error += (gmt_M_check_condition (GMT, GMT->common.J.active, "Option -J given more than once\n") ||
diff --git a/src/gmt_map.c b/src/gmt_map.c
index a88e358708f..577ac3346b9 100644
--- a/src/gmt_map.c
+++ b/src/gmt_map.c
@@ -5212,7 +5212,7 @@ GMT_LOCAL int gmtmap_init_polyconic (struct GMT_CTRL *GMT, bool *search) {
 
 	*search = false;
 	switch (GMT->current.proj.projection_GMT) {
-		case GMT_LINEAR:        error = gmtmap_init_linear (GMT, search); break;      /* Linear transformations */
+		//case GMT_LINEAR:        error = gmtmap_init_linear (GMT, search); break;      /* Linear transformations */
 		case GMT_POLAR:         error = gmtmap_init_polar (GMT, search); break;       /* Both lon/lat are actually theta, radius */
 		case GMT_MERCATOR:      error = gmtmap_init_merc (GMT, search); break;        /* Standard Mercator projection */
 		case GMT_STEREO:        error = gmtmap_init_stereo (GMT, search); break;      /* Stereographic projection */
@@ -5247,8 +5247,8 @@ GMT_LOCAL int gmtmap_init_polyconic (struct GMT_CTRL *GMT, bool *search) {
 			GMT->current.proj.scale[GMT_X] = GMT->current.proj.scale[GMT_Y] = GMT->current.proj.proj4_scl;
 			GMT->current.map.n_lon_nodes = 360;	GMT->current.map.n_lat_nodes = 180;
 			if (GMT->common.R.oblique) {
-				gmt_proj4_fwd (GMT, GMT->common.R.wesn[XLO], GMT->common.R.wesn[YLO], &xmin, &ymin);
-				gmt_proj4_fwd (GMT, GMT->common.R.wesn[XHI], GMT->common.R.wesn[YHI], &xmax, &ymax);
+				gmt_proj4_fwd(GMT, GMT->common.R.wesn[XLO], GMT->common.R.wesn[YLO], &xmin, &ymin);
+				gmt_proj4_fwd(GMT, GMT->common.R.wesn[XHI], GMT->common.R.wesn[YHI], &xmax, &ymax);
 				GMT->current.map.outside = &gmtmap_rect_outside;
 				GMT->current.map.crossing = &gmtmap_rect_crossing;
 				GMT->current.map.overlap = &gmtmap_rect_overlap;
@@ -5258,7 +5258,7 @@ GMT_LOCAL int gmtmap_init_polyconic (struct GMT_CTRL *GMT, bool *search) {
 				GMT->current.map.frame.check_side = true;
 			}
 			else {
-				gmtmap_xy_search (GMT, &xmin, &xmax, &ymin, &ymax, GMT->common.R.wesn[XLO], GMT->common.R.wesn[XHI], GMT->common.R.wesn[YLO], GMT->common.R.wesn[YHI]);
+				gmtmap_xy_search(GMT, &xmin, &xmax, &ymin, &ymax, GMT->common.R.wesn[XLO], GMT->common.R.wesn[XHI], GMT->common.R.wesn[YLO], GMT->common.R.wesn[YHI]);
 				GMT->current.map.outside = &gmtmap_wesn_outside;
 				GMT->current.map.crossing = &gmtmap_wesn_crossing;
 				GMT->current.map.overlap = &gmtmap_wesn_overlap;
@@ -5267,8 +5267,20 @@ GMT_LOCAL int gmtmap_init_polyconic (struct GMT_CTRL *GMT, bool *search) {
 				GMT->current.map.right_edge = &gmtmap_right_rect;
 				GMT->current.map.frame.horizontal = 2;
 			}
-			gmtmap_setinfo (GMT, xmin, xmax, ymin, ymax, GMT->current.proj.proj4_scl);
+			gmtmap_setinfo(GMT, xmin, xmax, ymin, ymax, GMT->current.proj.proj4_scl);
 			if (GMT->current.setting.map_frame_type & GMT_IS_FANCY) GMT->current.setting.map_frame_type = GMT_IS_PLAIN;
+#if (GDAL_VERSION_MAJOR >= 3 && GDAL_VERSION_MINOR >= 9 || GDAL_VERSION_MAJOR >= 4)
+			if (GMT->current.proj.projection == GMT_PROJ4_SPILHAUS) {	/* Spilhaus issues many "ERROR 1: Point outside of projection domain" */
+	#if ((PROJ_VERSION_MAJOR < 9) || (PROJ_VERSION_MAJOR == 9 && PROJ_VERSION_MINOR < 6))
+				GMT_Report(GMT->parent, GMT_MSG_ERROR, "To use the Spilhaus projection you need a GDAL library that was compiled with a PROJ version >= 9.6 and you don’t have that.\n");
+	#endif
+	#ifdef WIN32
+				CPLSetConfigOption("CPL_LOG", "NUL");
+	#else
+				CPLSetConfigOption("CPL_LOG", "/dev/null");
+	#endif
+			}
+#endif
 			break;
 	}
 	/* Now we only have to replace the pointers to the FWD and INV transform functions */
@@ -8476,7 +8488,7 @@ int gmt_grd_project (struct GMT_CTRL *GMT, struct GMT_GRID *I, struct GMT_GRID *
 
 				/* On 17-Sep-2007 the slack of GMT_CONV4_LIMIT was added to allow for round-off
 				   errors in the grid limits. */
-				if (gmt_M_x_is_lon (GMT, GMT_IN) && !gmt_M_is_dnan (x_proj)) {
+				if (gmt_M_x_is_lon (GMT, GMT_IN) && !gmt_M_is_dnan (x_proj) && !gmt_M_is_dinf(x_proj)) {	/* Spilhaus returns Inf instead of NaN */
 					while (x_proj < I->header->wesn[XLO] - GMT_CONV4_LIMIT) x_proj += 360.0;
 					while (x_proj > I->header->wesn[XHI] + GMT_CONV4_LIMIT) x_proj -= 360.0;
 				}
diff --git a/src/gmt_plot.c b/src/gmt_plot.c
index 1b0309d546e..51438d5c204 100644
--- a/src/gmt_plot.c
+++ b/src/gmt_plot.c
@@ -8313,8 +8313,10 @@ char *gmt_importproj4 (struct GMT_CTRL *GMT, char *pStr, int *scale_pos, char *e
 			//strcat(opt_J, "0/");
 	}
 
-	else	/* We don't return yet because we may have a +width/+scale to parse */
+	else {	/* We don't return yet because we may have a +width/+scale to parse */
 		GMT_Report (GMT->parent, GMT_MSG_INFORMATION, "This projection '%s' is not natively supported in GMT\n", prjcode);
+		strcat(opt_J, szProj4);
+	}
 
 #if 0
 	bool got_a = false, got_b = false;