def read_base(filename):
    f=mygis.Dataset(filename,mode="r")
    output=Bunch()

    variables=Bunch()
    for k in f.variables.keys():
        curvar=f.variables[k]
        if (k!="pr") and (k!="tasmin") and (k!="tasmax") and (k!="TREFMN") and (k!="TREFMX") and (k!="tas"):
            data=Bunch(data=curvar[:])
        else:
            data=Bunch()
        data.atts=copy.deepcopy(curvar.__dict__)
        # data.dims=copy.deepcopy(curvar.dimensions)
        data.dims=curvar.dimensions
        data.dtype=curvar.dtype
        variables[k]=data
        
    output.variables=variables
    output.global_attributes=copy.deepcopy(f.__dict__)
    # output.dimensions=copy.deepcopy(f.dimensions)
    output.dimensions=f.dimensions
    output.ncfile=f
    # f.close()
    return output