Add information on creation of reports and flood affected areas

[tomasholderness]

Individual flood reports are collected from a number of different platforms (Qlue, Pasangmata.com, Twitter, Telegram). Each source of reporting is confirmed in its own manner (i.e. has processes in place to filter spam, and only show info related to flooding) but these reports are from residents and are not further verified. Location and timestamps are generated by user's location at time of report submission to PetaBencana.id

Flood affected areas polygons come directly from BPBD DKI Jakarta. The are created on a combination of the resident reports from PetaBencana.id and on-the-ground human intelligence collected by BPBD and collated by the staff in the control room. The designation of a flooded area is not automated (albeit computer assisted) RW regions are marked as flooded, including estimated water depth (normally phoned-in by Kelurahan etc), by BPBD staff. The time stamp indicates when the flood affected area was first demarcated as such by BPBD. Flood affected areas are removed from the map as BPBD staff receive the all clear. I.e. if an area is marked as flooded on the map, this is a good indicator that it is currently affected by flood. There's no aggregation/averaging of this data.