Dar es Salaam/Ramani Huria

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Ramani Huria is a community-based mapping project that began in Dar es Salaam, Tanzania, training university students and local community members to create highly accurate maps of the most flood-prone areas of the city. As the maps have taken shape – their benefits have multiplied and their potential magnified, now serving as foundational tools for development within all socio-economic spheres beyond flood resilience.

Data collected as part of Ramani Huria conforms to a model. The Data Model specifies what types of attributes are collected, what answers are possible, and the style in which they are displayed on the OpenStreetMap website's rendering, Ramani Huria's own atlases (essentially QGIS styles), and the Government of Tanzania data portal. The model consists of three basic layers:

  1. Items that appear in the OpenStreetMap standard rendering, and therefore conform to an essentially universal schema - they should look, by and large, identical in the street map in any country. Examples include the usual classifications of roads and buildings; the usual elements of the street map.
  2. Items that do not appear in the OpenStreetMap standard rendering, but should nevertheless be invariant across multiple countries and contexts. Examples include drainage, which does not appear in detail as part of the usual street map style, but is nevertheless universal and should be tagged consistently regardless of the local context.
  3. Items that are specific to the local context, which do not appear in the OpenStreetMap standard rendering and are not particularly universal, but which are useful to support the specific goals of the local project and community. Examples include local health-care infrastructure which is organised in a context-specific fashion by the national Ministry of Health, or administrative divisions that don't easily fit into an Adm1, Adm2, Adm3 schema.

1) OpenStreetMap Core Features

Streets

Primary Key Value Comment OSM Style Street Map Atlas Style Drainage Atlas Style Flood Extent Atlas Style Government of Tanzania Style Photo
highway trunk Major arteries, always paved and double-lane with median. There are only two or three of these in Dar es Salaam. Examples include Nyerere Road, Morogoro Road, and Ali Hassan Mwinyi Road. Rendering-highway trunk L3005 MF.png Nyere road.jpg
primary Major roads in the city. Always paved. Usually double-lane. Examples include Kawawa and Kilwa roads. Rendering-highway primary neutral.png Kilwa Road.jpg
secondary Connecting roads in the city. Paved, usually single-lane. Examples include Nelson Mandela and Kigogo roads. Rendering-highway secondary neutral.png Kigogo Road.jpg
tertiary Roads connecting the primary and secondary roads into neighbourhoods. Often paved, but not universally so. Examples include Aga Khan road. Rendering-highway tertiary neutral.png Tertiary road.jpg
unclassified Mostly small residential roads in informal neighborhoods. Sometimes paved for the first few meters off the larger roads, but otherwise unpaved. Not usually gridded, rather meandering. Rendering-highway unclassified.png Unclassified road in Kivulini.jpg
residential Small residential roads in planned neighbourhoods. Usually arranged in a recognisable grid. Sometimes paved for the first few meters off the larger roads, but otherwise unpaved. Rendering-highway residential.png Residential road.jpg
footway Walking (or in a pinch, cycling or motorcycling) paths through neighbourhoods. Tend to meander between buildings. Too narrow and rough for car traffic. Path osm.png Footway.jpg
name [Name of Street]
surface asphalt
concrete
unpaved
cobblestones
smoothness good Possible to drive consistently at the speed limit without worrying about imperfections
intermediate Occasional imperfections requiring caution or slow passage
bad Many imperfections, not possible to drive consistently at the speed limit
very_bad Impossible to ever drive at the speed limit, better to use 4-wheel drive
horrible You'll know it when you see it.
width (in meters of street width)
ele:relative [elevation in meters] The elevation of the road surface above the surrounding land
oneway yes (direction of traffic, NOT the number of lane)
no
bridge yes
viaduct (add layer=1)
description

Buildings

Primary Key Value Comment OSM Style Street Map Atlas Style Drainage Atlas Style Flood Extents Atlas Style Government of Tanzania Style
building residential
commercial
apartments
industrial
public
school
utility
construction
industrial
commercial
hospital
name [Name of Building]
building:levels [Number of levels in the building] The ground floor is 1
ele:threshold [elevation of ground floor/entrance in meters] The elevation of the entrance (ground floor) above the street level.
building:material brick
cement_block
concrete
glass
loam
plaster
wood
metal
building:roof tiles
concrete
metal
wood
plastic
grass
addr:housenumber [Address of the building] address number of the building, ie 25 or 19A
addr:street [Name of Street]
addr:city
addr:ward [Ward]
addr:sub-ward [Sub-Ward]
amenity atm
bank
bar
cafe
clinic
college
courthouse
embassy
fire_station
fuel
hospital
kindergarten
library
marketplace
parking
place_of_worship
pharmacy
police
post_office
pub
public_building
restaurant
school
townhall
office company
government
insurance
lawyer
political_party
yes
shop alcohol
art
bakery
beauty
beverages
bicycle
books
butcher
car
car_parts
car_repair
chemist
clothes
convenience
copyshop
cosmetics
doityourself
electronics
furniture
greengrocer
hairdresser
houseware
jewellery
kiosk
mobile_phone
pastry
shoes
stationary
supermarket
tailor
yes
tourism attraction
guest_house,
hotel
yes
bed_count [Number of beds] Used for hospitals (and hotels?)
religion muslim If a place of worship
christian

2) Non Street Map but universally consistent

Drainage - Ditch

This refers to unlined trenches that are part of, or connect to, the city's drainage system.

Primary Key Value Comment OSM Style Drainage Atlas Style Flood Extents Atlas Style Government of Tanzania Style Photo
waterway ditch Drain ditch open.jpg
covered yes
no
blockage dirt
concrete
rubbish
no
width [Number of meters wide]
depth [Number of meters deep]

Drainage - Drain

  • The dimensions here are measured using tapes and staffs. Surveyors collect most dimensions in cm, which are then converted into decimal meters prior to placement in OSM in order to maintain consistent units.
Primary Key Value Comment OSM Style Drainage Atlas Style Flood Extents Atlas Style Government of Tanzania Style Photo
waterway drain Drains are ubiquitous in Dar es Salaam, and are not well-mapped. Challenged include placing drains correctly parallel to roads (GPS tracks tend to meander in and out of the roadway) and identifying various point features (vertical pipes/pools, connections, culverts, incoming building drains, blockages, etc). Drain open trapezoid clean.jpg
covered yes Drain cover concrete panel handles.jpg
no Drain open trapezoid 3.jpg
covered:material concrete Concrete slab covering drain Concrete covering slab missing.jpg
grating Metal grating or grill; can be seen through but not fallen through Drain grating metal covered.jpg
metal Solid metal covering
wood Wood covering over drains, often made by local residents or businesses
material concrete
steel
asphalt
sand
plants
trees
gravel
blockage dirt
concrete
solid_waste Point blockage solid waste.jpg
no
width [Number of meters wide] If profile is rectangular or boxed_rectangular
width_top [Number of meters wide at top] If profile is trapezoidal or elliptical
width_bottom [Number of meters wide at bottom] If profile is trapezoidal
depth [Number of meters deep]
profile open_rectangular Drain rectangular concrete.jpg
tabulated Tabulated drain.jpg
trapezoid Drain trapezoid silted high sides.jpg
elliptical
ele [Elevation - Number of meters above sea level] Cannot be reliably assessed by OSM mappers, therefore we use ele:relative_to_road (see below). If and when a Digital Elevation Model (DEM) is available, elevation will be calculated.
ele:relative_to_road [elevation difference to nearest road surface in meters] As OSM mappers do not usually have a method of measuring absolute elevation with the precision required for a drain, we measure the elevation difference to the nearest road surface. If and when a Digital Elevation Model (DEM) is available, the road surfaces tend to be fairly accurate and can then be used to calculate the absolute elevation of the nearby drain using this difference.

Drainage - Underground Drain

  • Note: it may not be obvious that an underground drain can be mapped! However, often a culvert or a short segment of drain that passes through an obstacle can be mapped by looking at the start and endpoints. In the event that the trajectory of an underground drain cannot be reliably assessed, only the start and endpoints will be taken as point features (see next table).
Primary Key Value Comment OSM Style Drainage Atlas Style Flood Extents Atlas Style Government of Tanzania Style Photo
waterway drain
AND
tunnel yes
culvert If feature is a culvert Culvert2.jpg
layer -1 (why -1?)
profile round Round culvert entrance.jpg
boxed_rectangular Rectangular culvert.jpg
channels [integer number of channels - only needed if more than 1 channel] Often rather than a single culvert pipe, large drains widen out before passing through a roadway, and have multiple pipes/channels. If they are identical in profile and size, it is easier for hydrologists to manage if the crossing is simply labelled as multi-channel, rather than attempting to map all channels as separate lines. Drain culvert multichannel.jpg
diameter [Number of meters in diameter] if profile is round
width [Number of meters width] if profile is boxed_rectangular
height [Number of meters height] if profile is boxed_rectangular
material concrete Concrete culvert.jpg
steel Culvert metal blockage partial.jpg
blockage dirt
concrete
solid_waste
no
ele [Elevation - Number of meters above sea level] Cannot be reliably assessed by OSM mappers, therefore we use ele:relative_to_road (see below). If and when a Digital Elevation Model (DEM) is available, elevation will be calculated.
ele:relative_to_road [elevation difference to nearest road surface in meters] As OSM mappers do not usually have a method of measuring absolute elevation with the precision required for a drain, we measure the elevation difference to the nearest road surface. If and when a Digital Elevation Model (DEM) is available, the road surfaces tend to be fairly accurate and can then be used to calculate the absolute elevation of the nearby drain using this difference.

Drainage - Point Feature

There are a number of features along drains in Dar es Salaam that occur at a specific point rather than along the whole line segment. These include features such as silt traps, small-diameter entry pipes from nearby buildings, bridges, pump sites, culvert entries, or areas in need of repair. These are nodes, rather than lines, and may or may not be rendered in the street map or atlas styles.

Primary Key Value Comment OSM Style Drainage Atlas Style Flood Extents Atlas Style Government of Tanzania Style Photo
waterway drain:silt_trap Vertically-walled pools, somewhat deeper than the drains themselves, where water slows down and silt settles in a single spot where it is easily removed. Silt trap.jpg
drain:culvert_entrance Point where a drain goes underground - to be used where the culvert cannot be mapped as a line segment (as when the culvert is too long to reliably know where it goes underground). If the culvert can be reliably mapped as a line segment, that should be done instead of using this tag.
drain:outflow Point where a drain empties into a water body such as a stream, river, lake, or ocean.
drain:pipe_inflow Drains frequently have small-gauge pipes entering them from nearby buildings.
drain:building_drain
drain:bridge A small pedestrian bridge where people can cross the drain. This tag specifically refers to a bridge that is not part of an existing road or track (if the bridge is part of an existing road or footway trace, it does not need to be rendered as a point feature). May be concrete, as in the case of those installed by the drain installers, or a wooden structure placed by local residents or businesses. Walkway over drain concrete.jpgWalkway wooden bridge pedestrian.jpg
drain:crossing Any crossing that hasn't been identified in some other way (such as a culvert).
drain:no_crossing Any place where a drain simply butts up against an obstacle and doesn't cross.
drain:needs_repair
ele:relative_to_road [elevation difference to nearest road surface in meters]
Public Water Source
Primary Key Value Comment OSM Style Atlas Style Government of Tanzania Style Photo
amenity drinking_water
name
man_made water_tower
water_well
water_tap
bore_hole
water_pump
protected_spring
water_works
water_tank
pump powered
manual
no
pump:active yes
no
natural creek
stream
spring
water
drinking_water yes
no
operational_status operational
needs_maintenance
closed
out_of_order

Public Toilets

Primary Key Value Comment OSM Style Atlas Style Government of Tanzania Style Photo
amenity toilet
toilets:disposal flush
pitlatrine
bucket
chemical
toilets:access public
permissive(private but access is not restricted)
customers
fee yes; no
cost [Value of fee]
name [Name of toilet]
toilets:num_chambers [Number of toilets]
operator [Name of operator] For example: "Ilala Municipal Council" or "Tandale Sacco"
opening_hours [Opening hours of toilet] In a 24 hours, ranged format: 08:30­15:45
wheelchair yes
no
limited
toilets:handwashing yes
no

Solid Waste

Primary Key Value Comment OSM Style Street Map Atlas Style Drainage Atlas Style Flood Extents Atlas Style Government of Tanzania Style
amenity waste_disposal
recycling
waste_basket
waste <type of waste>
operator <name of operator>
landuse dump
dump:official yes
no

Open Areas

Primary Key Value Comment OSM Style Atlas Style Government of Tanzania Style
landuse brownfield Brownfield is a piece of land that has been previously built up and then cleared (a good example is the large field in Ndugumbi where they have been launching the drones).
greenfield Greenfield describes undeveloped land scheduled for development
cemetery
grass
park
playground
recreation_ground
natural water
wetland Ramani Huria's focus is flood resilience, and therefore emphasises mapping historical flood extents. For the moment, we include these in the database as wetlands.
wetland:flood_extent I'd like to include something like this!
wetland:flood_extent_year And even more this! This data can be collected by transect (household surveys asking what year they experienced flooding), and could be useful if we can figure out a way to document it!

Administration Boundaries

Primary Key Value Comment OSM Style Atlas Style Government of Tanzania Style
admin_level [Administration level] 9 = ward

10 = subward

boundary administrative
name [Name of Ward]
place ward; subward

Education

Primary Key Value Comment OSM Style Atlas Style Government of Tanzania Style
addr:street
addr:house number
amenity kindergarten
school
collage
university
opening_hours <days/time of opening>
contact:phone
operator <name of operator(operating authority)>
operator:type government
ngo
community
religious
public
private
capacity <number of student/pupills>
fee yes
no
religion <if the school is associated with a particular religion>

Healthcare

Primary Key Value Comment OSM Style Atlas Style Government of Tanzania Style
addr:street <street name>
addr:housenumber
name
operator
operator:type government
ngo
community
religious
public
private
amenity clinic
doctors
hospital
dentist
opening_hours <days/times of opening>
contact:phone
bed_count (for hospitals,clinics;the number of beds)
healthcare:specialty community
emergence
general
women
traditional
paediatrics
geriatricts
mental_heath
social_care
emergency yes
no
description

Services

Religious facilities

Primary Key Value Comment OSM Style Atlas Style Government of Tanzania Style
amenity place_of_worship
religion christian
muslim
buddhist
jewish
hindu
sikh
denomination catholic
orthodox
protestant
sunni
shia
sufi
etc(based on value for 'religion')
building cathedral
mosque
chapel
service_times <time of services>

Shops and markets

Primary Key Value Comment OSM Style Atlas Style Government of Tanzania Style
addr:district
addr:city
addr:street
amenity marketplace
shop alcohol
art
bakery
beauty
beverages
bicycle
books
butcher
car
car_parts
car_repair
chemist
clothes
convenience
copyshop
cosmetics
doityourself
electronics
furniture
greengrocer
hairdresser
houseware
jewellery
kiosk
kiosk
mobile_phone
pastry
shoes
stationary
supermarket
tailor
yes
name
open_hours

Offices

Primary Key Value Comment OSM Style Atlas Style Government of Tanzania Style
addr:district
addr:city
addr:street
office government
lawyer
company
ngo
telecommunication
political_party
yes
name
opening_hours

Financial institution

Primary Key Value Comment OSM Style Atlas Style Government of Tanzania Style
addr:district
addr:city
addr:street
amenity mobile_money_agent
bureau_de_change
bank
atm
microfinance_bank
saccos
money_transfer
post_office
name <name of facility>
operator <bank name>
network <if mobile money>

multiple values,semicolon delimited.

options: airtelmoney,mpesa,tigopesa

<if atm>

visa,mastercard,maestro,interswitch, other?

opening_hours

Other points of interest

Safety and security( police,fire services),tourism,fuel stations,communications towers,etc

Primary Key Value Comment OSM Style Atlas Style Government of Tanzania Style
name
amenity bar
cafe
car_wash
cinema
community_centre
court_house
embassy
fast_food
fire_station
fuel
gym
pub
library
pharmacy
parking
police
post_office
restaurant
social_facility
studio
theatre
townhall
veterinary
tourism hotel
motel
guest_house
museum
attraction
gallery
hostel
information
viewpoint
rooms <number of rooms available in a hotel,guesthouse etc>
beds <number of beds available in a hotel,guesthouse etc>
fuel <type of fuel;electric,petrol,diesel,kerosene>
operator <company running the amenity>
cuisine regional
local
indian
studio audio
video
television
radio
man_made yes
communications_tower
mast
tower
phone <phone number>