Tuhia tētahi tohutoro mō tēnei wāhanga - I whakamahia e te tākuta o Ingarangi a John Snow tētahi mahere rite ki a Voronoi i te tau 1854 hei whakaahua i te nuinga o ngā tāngata i mate i te pakarutanga o te mate pukupuku o Broad Street
i noho tata atu ki te papu wai o Broad Street kua pangia i ētahi atu papu wai.