Make sure intensity subset matches tiled region if given (#4130)

* Make sure intensity subset matches tiled region if given

If an intensity grid is given, and a remote earth_relief grid is given, then when the intensity grid is read in and we specify the subregion wesn, make sure this region matches the possibly adjusted tile_wesn due to rounding in gmt_remote.c  See #4124 for background.

* Update grdimage.c

* Update grdimage.c

Actually, similar problem cased the issue to begin with.

Author: PaulWessel

src/grdimage.c

@@ -901,8 +901,9 @@ EXTERN_MSC int GMT_grdimage (void *V_API, int mode, void *args) {
 	}
 
 	if (n_grids) {	/* Get grid dimensions */
-		n_columns = gmt_M_get_n (GMT, wesn[XLO], wesn[XHI], Grid_orig[0]->header->inc[GMT_X], Grid_orig[0]->header->registration);
-		n_rows = gmt_M_get_n (GMT, wesn[YLO], wesn[YHI], Grid_orig[0]->header->inc[GMT_Y], Grid_orig[0]->header->registration);
+		double *region = (gmt_file_is_tiled_list (API, Ctrl->In.file[0], NULL, NULL, NULL)) ? API->tile_wesn : wesn;	/* Make sure we get correct dimensions if tiled grids are used */
+		n_columns = gmt_M_get_n (GMT, region[XLO], region[XHI], Grid_orig[0]->header->inc[GMT_X], Grid_orig[0]->header->registration);
+		n_rows = gmt_M_get_n (GMT, region[YLO], region[YHI], Grid_orig[0]->header->inc[GMT_Y], Grid_orig[0]->header->registration);
 	}
 
 	if (Ctrl->D.active) {	/* Trust the info from gdal to make it more stable against pixel vs grid registration troubles */
@@ -932,11 +933,11 @@ EXTERN_MSC int GMT_grdimage (void *V_API, int mode, void *args) {
 	/* If given, get intensity grid or compute intensities (for a constant intensity) */
 
 	if (use_intensity_grid) {	/* Illumination wanted */
-
+		double *region = (gmt_file_is_tiled_list (API, Ctrl->In.file[0], NULL, NULL, NULL)) ? API->tile_wesn : wesn;	/* Subset to pass to GMT_Read_Data if data set is tiled */
 		GMT_Report (API, GMT_MSG_INFORMATION, "Allocates memory and read intensity file\n");
 
 		/* Remember, the illumination header was already read at the start of grdimage */
-		if (!Ctrl->I.derive && GMT_Read_Data (API, GMT_IS_GRID, GMT_IS_FILE, GMT_IS_SURFACE, GMT_DATA_ONLY, wesn, Ctrl->I.file, Intens_orig) == NULL) {
+		if (!Ctrl->I.derive && GMT_Read_Data (API, GMT_IS_GRID, GMT_IS_FILE, GMT_IS_SURFACE, GMT_DATA_ONLY, region, Ctrl->I.file, Intens_orig) == NULL) {
 			Return (API->error);	/* Failed to read the intensity grid data */
 		}
 		mixed = grdimage_clean_global_headers (GMT, Intens_orig->header);