PROCEDURE: options, str, tag_name, value PURPOSE: Add (or change) an element of a structure. This routine is useful for changing plotting options for tplot, but can also be used for creating limit structures for other routines such as "SPEC3D" or "CONT2D" INPUT: str: Case 1: String (or array of strings) The limit structure associated with the "TPLOT" handle name is altered. Warning! wildcards accepted! "*" will change ALL tplot quantities! Case 2: Number (or array of numbers) The limit structure for the given "TPLOT" quantity is altered. The number/name association is given by "TPLOT_NAMES" Case 3: Structure or not set (undefined or zero) Structure to be created, added to, or changed. tag_name: string, tag name for value. value: (any type or dimension) value of new element. NOTES: if VALUE is undefined then it will be DELETED from the structure. if TAG_NAME is undefined, then the entire limit structure is deleted. KEYWORDS: DEFAULT: If set, modify the default limits structure rather than the regular limits structure (tplot variables only). SEE ALSO: "GET_DATA","STORE_DATA", "TPLOT", "XLIM", "YLIM", "ZLIM", "STR_ELEMENT" CREATED BY: Jasper Halekas Modified by: Davin Larson LAST MODIFICATION: @(#)options.pro 1.19 99/04/07