Methodology

Atlas of the Human Planet 2019 - A compendium of urbanisation dynamics in 239 countries

Analytics

The reporting of Country Urbanisation Briefs uses a standard template.
The two pages template for the majority of the countries contains the following insights:

  • a map of the GHSL Settlement Model (GHS-SMOD) grid around the most populated urban centre in the country
  • degree of urbanisation statistics
  • hierarchy of urban centres
  • societal variables trend
  • urbanisation factors
  • urbanisation dynamic
  • land use efficiency (SDG 11.3.1)
  • demand for urban policy
  • built-up area per capita by settlement typology and epoch
  • key statistics for the most populated urban centre in the country

Inputs and scale of analysis for the production of the Country Urbanisation Briefs


Inputs and scale of analysis for the production of the Country Urbanisation Briefs content


Country urbanisation briefs contents and methodology


ContentMethod
The share of urban population in 2015 Refers to the ratio between urban populations (sum of urban centre, urban cluster, dense and semi-dense urban cluster, suburban grid cell) over the total population of the territory in the epoch 2015. The value is obtained summing GHS-POP values per GHS-SMOD settlement types (epoch layer 2015) within the corresponding GADM 2.8 extent
The number of urban centres in 2015 Refers to the number of urban centres entities in the territory in the epoch 2015. It is based on the GHS-SMOD urban centre entities in the epoch 2015 within the GADM 2.8 extent.
The number of urban centre above 300k inhabitants in 2015 Refers to the number of urban centres entities exceeding 300,000 inhabitants in the epoch 2015 in the corresponding territory. It is based on the GHS-SMOD urban centre entities in the epoch 2015 within the GADM 2.8 extent, and the sum of population in the entities from GHS-POP epoch 2015.
Percentage of total population by settlement class Refers to the share of the total population accounted in each of the 7 GHS-SMOD settlement classes (urban centre, urban cluster, dense urban cluster, semi-dense urban cluster, suburban grid cell, rural cluster, low density rural grid cell, very low density grid cell) in the epochs 1975 – 1990 – 2000 – 2015. It is obtained with the ratio of the total sum of population from the GHS-POP (at the corresponding epoch layer) in each class extracted from the GHS-SMOD (at the corresponding epoch layer), and the total population of the territory obtained summing the GHS-POP values (at the corresponding epoch layer) within the GADM 2.8 extent.
Count of total population by settlement class Refers the total population accounted in each of the 7 GHS-SMOD settlement types (urban centre, urban cluster, dense urban cluster, semi-dense urban cluster, suburban grid cell, rural cluster, low density rural grid cell, very low density grid cell) in the epochs 1975 – 1990 – 2000 – 2015. It is obtained as the sum of population from the GHS-POP (at the corresponding epoch layer) in each class extracted from the GHS-SMOD (at the corresponding epoch layer), and the total population of the territory obtained summing the GHS-POP values (at the corresponding epoch layer) within the GADM 2.8 extent.
Hierarchy of urban centres Refers to the total number of urban centres entities classified into population size classes (less than 250,000; between 250,000 and 1,000,000; between 1,000,000 and 5,000,000; between 5,000,000 and 10,000,000; and above 10,000,000) in the territory in the epochs 1975 – 1990 – 2000 – 2015. It is based on the GHS-SMOD urban centre entities in the corresponding epoch within the GADM 2.8 extent, and summing the population in the entities from GHS-POP (for the corresponding epoch).
Societal variables trend Refers to the multi-temporal changes of the population and built-up areas in the territory between 1975 and 2015. The trajectories displays the dynamics of the essential societal variables (D. Ehrlich et al. 2018) of each territory compared to the median trajectories of the other territories grouped by income class. The more the trajectory is flat, the more populations grew without expansion of built-up areas, the more the trajectory is vertical, the more the built-up areas expanded with little demographic growth. While Low Income Countries are close to the first trajectory, High Income Countries more frequently developed with the latter one. The trajectory is obtained by summing the total built-up areas and population from GHS-BUILT and GHS-POP in the corresponding epoch respectively within the matching GADM 2.8 extent.
Urbanisation factors Refers to the classification of the urbanisation process according to the method “Demographic Factors of Change in Urbanisation processes” (M. Melchiorri et al. 2019). Territories are classified into one of ten cases depending on changes (delta) between 1975 and 2015 in total population, urban, rural populations and degree of urbanisation. The chart plots the trajectory of the territory in a delta rural population (X), delta urban population (Y) chart. Territories with the marker of the final year (2015 and coloured according to the classification) laying in a red sector encountered a process of increasing degree of urbanisation, the other ones laying in a blue sector encountered a process of decline of the degree of urbanisation. The classification is obtained through the method explained in (M. Melchiorri et al. 2019).
National-specific definition and figures of urban areas Recalls the definition of cities and urban areas for the territory that is reported in the World Urbanization Prospects: The 2018 Revision (Data source urban population).
Urbanisation dynamics Refers to the urbanisation status (share of urban population in 2015) and dynamics (share of urban population change between 1990 and 2015). It positions the territory comparing it to global degree of urbanisation in 2015 (76.5%) and the global degree of urbanisation change 1990 – 2015 (3%). Depending on the position of the marker, the territory is more/less urbanised than global average, and has urbanised faster/slower compared to global average. The chart displays a heat map plotting the density of territories distribution in the plot. The degree of urbanisation is obtained as described for the field “Degree of urbanisation” above, the change in the degree of urbanisation change is computed as difference between the degree of urbanisation 2015 minus degree of urbanisation 1990.
Land Use Efficiency –SDG 11.3.1 Refers to the estimation of the Land Use Efficiency indicator (SDG 11.3.1) per each settlement type in the GHS-SMOD between the epochs 1990 and 2015. In addition to the per type LUE value, an overall LUE value for the territory is provided. The values are computed on the basis of the application of GHSL as baseline for the indicator (Michele Melchiorri et al. 2019).
Demand for urban policy Refers to the relative change in total and urban population of the territory between 1990 and 2015 and the net change in urban population (marker size). It is obtained as difference between the values explained in the “Degree of urbanisation” field for urban classes, and totals in the corresponding epochs.
Built-up area per capita by settlement typology and epoch Refers to the amount of built-up areas per capita (m2) per settlement type and epoch (the average for the territory is provided in black markers). It is obtained by a ratio between the sum of built-up areas (from GHS-BUILT) and that of population (from GHS-POP) per each settlement type (delineated from GHS-SMOD) at the corresponding epoch within the matching GADM 2.8 extent.
Urban Centre information Information about the most populated urban centre in the matching GADM 2.8 extent are extracted from the GHS-UCDB (A. Florczyk et al. 2019). Information include the population figure, the areal extent, population density (inhabitants km2), built-up areas surface and built-up areas per capita (m2) for the epoch 2015. Additional information (if available) include river basin name, biome type, climate class, soil type, mean elevation above sea level, average temperature and precipitation (all variables for the latest epoch available in the GHS-UCDB). Additional information about exposure to natural hazards –Modified Mercalli Index, and heatwave index, population and built-up areas exposed to flood and storm surge, are displayed if occur. The last paragraph (marked with the SDG 11 icon) displays the LUE value (SDG 11.3.1) of the urban centre between 1990 and 2015 and the share of the urban centre population accounted in areas with dense presence of green and the share of open spaces (proxy for SDG 11.7.1)
NDVI and vegetated surfaces Refers to the areal extent of the urban centre in 2015 with high, low or medium presence of green plus the NDVI value. It is computed based on the method of (Corbane, Pesaresi, et al. 2018).
PM2.5 emission Refers to the total PM2.5 emissions in tonnes per year in the urban centre at the corresponding epoch 1975 – 1990 – 2000 – 2012. The value is obtained from the GHS-UCDB (by aggregation of emissions per sector).
CO2 emission Refers to the total CO2 emissions in tonnes per year in the urban centre at the corresponding epoch 1975 – 1990 – 2000 – 2012. The value is obtained from the GHS-UCDB (by aggregation of emissions per sector).