Needed new constant GMT_GRID_IS_GEO|CARTESIAN for API usage

Author: PaulWessel

src/gmt_api.c

@@ -3537,8 +3537,8 @@ GMT_LOCAL struct GMT_DATASET *api_import_dataset (struct GMTAPI_CTRL *API, int o
 		if (!D_obj->min) D_obj->min = gmt_M_memory (GMT, NULL, D_obj->n_columns, double);
 		if (!D_obj->max) D_obj->max = gmt_M_memory (GMT, NULL, D_obj->n_columns, double);
 	}
-	gmtlib_set_dataset_minmax (GMT, D_obj);	/* Set the min/max values for the entire dataset */
 	D_obj->geometry = geometry;			/* Since gmtlib_read_table may have changed it */
+	gmtlib_set_dataset_minmax (GMT, D_obj);	/* Set the min/max values for the entire dataset */
 	if (!via) API->object[this_item]->data = D_obj;	/* Retain pointer to the allocated data so we use garbage collection later */
 	return (D_obj);
 }
@@ -4651,6 +4651,7 @@ GMT_LOCAL int api_export_grid (struct GMTAPI_CTRL *API, int object_ID, unsigned
 	if (S_obj->region) {	/* See if this is really a subset or just the same region as the grid */
 		if (G_obj->header->wesn[XLO] == S_obj->wesn[XLO] && G_obj->header->wesn[XHI] == S_obj->wesn[XHI] && G_obj->header->wesn[YLO] == S_obj->wesn[YLO] && G_obj->header->wesn[YHI] == S_obj->wesn[YHI]) S_obj->region = false;
 	}
+	if (mode & GMT_GRID_IS_GEO) gmt_set_geographic (GMT, GMT_OUT);	/* From API to tell grid is geographic */
 	gmtlib_grd_set_units (GMT, G_obj->header);	/* Ensure unit strings are set, regardless of destination */
 	switch (S_obj->method) {
 		case GMT_IS_FILE:	/* Name of a grid file on disk */

src/gmt_resources.h

@@ -251,6 +251,7 @@ enum GMT_enum_dimindex {
 };
 
 enum GMT_enum_gridio {
+	GMT_GRID_IS_CARTESIAN	   = 0U,    /* Grid is not geographic but Cartesian */
 	GMT_GRID_IS_REAL	   = 0U,    /* Read|write a normal real-valued grid */
 	GMT_GRID_ALL		   = 0U,    /* Read|write both grid header and the entire grid (no subset) */
 	GMT_GRID_HEADER_ONLY	   = 1U,    /* Just read|write the grid header */
@@ -261,7 +262,8 @@ enum GMT_enum_gridio {
 	GMT_GRID_NO_HEADER	   = 16U,   /* Write a native grid without the leading grid header */
 	GMT_GRID_ROW_BY_ROW	   = 32U,   /* Read|write the grid array one row at the time sequentially */
 	GMT_GRID_ROW_BY_ROW_MANUAL = 64U,   /* Read|write the grid array one row at the time in any order */
-	GMT_GRID_XY		   = 128U}; /* Allocate and initialize x,y vectors */
+	GMT_GRID_XY		   = 128U,  /* Allocate and initialize x,y vectors */
+	GMT_GRID_IS_GEO		   = 256U}; /* Grid is a geographic grid, not Cartesian */
 
 /* These lengths (except GMT_GRID_VARNAME_LEN80) must NOT be changed as they are part of grd definition */
 enum GMT_enum_grdlen {