;+
; NAME:
;	HDFeditSDS
;
; PURPOSE:
;	Replaces and HDF's SDS with new data
;
; AUTHOR:
;	Alex Fraser
;
; CATEGORY:
;	HDF Utility
;
;
; CALLING SEQUENCE:
;	see example
;
;
; INPUTS:
;	filename: filename (including path) of the HDF file
;	sdsname: string containing name of the SDS you want to modify
;	newdata: a variable containing the new data you want to write to the HDF SDS
;
; KEYWORDS:
;	none
;
;
; OUTPUTS:
;	Edits an HDF file with new data in the specified SDS
;
;
; RESTRICTIONS:
;	No error checking
;
;
; EXAMPLE:
;	this code replaces test.hdf's Longitude SDS with the data contained in the variable named newdata
;	HDFeditSDS('c:\test.hdf', 'Longitude', newdata)
;
;
; MODIFICATION HISTORY:
;
;	Written by Alex Fraser, 2007.
;-



PRO HDFeditSDS, filename, sdsname, newdata

sdfileid=hdf_sd_start(filename, /rdwr)

; Find the index of the "Gridded Data" SDS.
index = HDF_SD_NAMETOINDEX(sdFileID, sdsname)

; Select the Gridded Data SDS.
thisSdsID = HDF_SD_SELECT(sdFileID, index)

HDF_SD_AddData, thisSdsID, newdata

hdf_sd_end, sdfileid

END