def build_srcdict(gta, prop):
    """Build a dictionary that maps from source name to the value of a source property

    Parameters
    ----------

    gta : `fermipy.GTAnalysis`
        The analysis object

    prop : str
        The name of the property we are mapping


    Returns
    -------

    odict : dict
        Dictionary that maps from source name to the value of the specified property

    """
    o = {}
    for s in gta.roi.sources:
        o[s.name] = s[prop]
    return o