Below is my query to identify what hazard type does the buildings belong:

def floodhazard_tbl(request):
    if request.method == "GET":
        reference_high = FloodHazard.objects.filter(hazard='High')
        reference_medium = FloodHazard.objects.filter(hazard='Medium')
        reference_low = FloodHazard.objects.filter(hazard='Low')

        #get all ids based on filter
        ids_high = reference_high.values_list('id', flat=True)
        ids_medium = reference_medium.values_list('id', flat=True)
        ids_low = reference_low.values_list('id', flat=True)

        # create a list
        k = []
        response_high = []
        response_medium = []
        response_low = []
        bldg_id_high = []
        bldg_ids_high = []
        bldg_id_medium = []
        bldg_ids_medium = []
        filtered_bldg = []

        # this code is results a messy JSON data that need underscore.js to manipulate
        # in order for us to use datatables
        for myid in ids_high:
            getgeom = FloodHazard.objects.get(id=myid).geom
            response_high = PolyStructures.objects.filter(geom__intersects=getgeom).values(
                'brgy_locat', 'municipali').annotate(counthigh=Count('brgy_locat'))
            bldg_id_high = filter(None,response_high.values_list('id',flat=True))
            bldg_ids_high = bldg_ids_high + bldg_id_high
            k.append(response_high)
            

        for myid in ids_medium:
            getgeom = FloodHazard.objects.get(id=myid).geom
            response_medium = PolyStructures.objects.exclude(id__in=bldg_ids_high).filter(geom__intersects=getgeom).values(
                'brgy_locat', 'municipali').annotate(countmedium=Count('brgy_locat'))
            bldg_id_medium = filter(None,response_medium.values_list('id',flat=True))
            bldg_ids_medium = bldg_ids_medium + bldg_id_medium
            k.append(response_medium)

        filtered_bldg = bldg_ids_medium + bldg_ids_high

        for myid in ids_low:
            getgeom = FloodHazard.objects.get(id=myid).geom
            response_low = PolyStructures.objects.exclude(id__in=filtered_bldg).filter(geom__intersects=getgeom).values(
                'brgy_locat', 'municipali').annotate(countlow=Count('brgy_locat'))
            k.append(response_low)


        #to_json = list(k for k,_ in itertools.groupby(k))
        result = []
        for d in chain.from_iterable(k):
            result.append(d)
            
        return HttpResponse(list(json.dumps(result)), content_type='application/json')

I have this method(algo):

• After the response_high query, I get all the building that DID NOT intersect to the HIGH type of hazard and so on and exclude it in the next query(intersects) to avoid duplication (because there is a tendency that the building will intersect to the hazard polygon several times).

The code works but the response is slow, take 6 seconds to show the output. And it is messed up, any optimization "technique" is appreciated. Thanks!