getFeature problem

[Myunghwa Hwang]

I'm trying to retrieve attributed values for selected polygon.
By using python mapscript and postgis layer, I tried to get a feature by querybypoint.
In the following code, a feature by getFeature has no bounding box.
The minimum x, y and the maximum x, y are all -1.
So any attribute was not retrieved. 
Anybody has any idea of this problem?


def getNearFeat(qpoint, map):
    # get query layer
    qlayer = map.getLayerByName('blockgroup')
    qlayer.template = 'query_result.html'
    qlayer.tolerance = 1000 # Unit is meter
    # query the query layer
    qlayer.queryByPoint(map, qpoint, ms.MS_MULTIPLE, 1000)
    numResults = qlayer.getNumResults()
    results = qlayer.getResults()
    # retrieve shape index for selected features
    if (numResults > 0):
        featAtts = []
        qlayer.open()
        for i in range(numResults):
            att = []
            query_result = results.getResult(i)
            afeat = qlayer.getFeature(query_result.shapeindex, query_result.tileindex)
            if afeat:
                for j in range(qlayer.numitems):
                    att.append(afeat.getValue(j))
                featAtts.append(att)
        qlayer.close()
    return featAtts