There's also things like this: http://data.london.gov.uk/datafiles/crime-community-safety/ambulance-weapon-injury-ward.xml http://data.london.gov.uk/datafiles/c

There's also things like this: http://data.london.gov.uk/datafiles/crime-community-safety/ambulance-weapon-injury-ward.xml http://data.london.gov.uk/datafiles/crime-community-safety/a... <Ward_Code>00AAFB</Ward_Code> <Ward_Name>Aldgate</Ward_Name> <District_Code>00AA</District_Code> <District_Name>City of London</District_Name> <Count_12-2007/> <Count_1-2008/> <Count_2-2008/> <Count_3-2008/> <Count_4-2008/> <Count_5-2008/> <Count_6-2008/> So... is that zero (a safe area) or no data (an unknown quantity)?