In a humanitarian crisis, relief agencies need rapid answers to questions about 'where'. Where are the greatest needs? Where are the gaps that need to be filled? MapAction is a non-governmental organisation (NGO) that works in disaster zones providing frequently updated situation maps showing where relief help is most urgently needed. MapAction has run two missions in Haiti: in 2008 in response to a string of tropical storms that struck the north of the country; and in 2010 after the earthquake.