Leaving No One of the Map: A guide for Gridded Population Data for Sustainable Development

With this guide, the UNSDSN Thematic Research Network on data and Statistics (TRENDS) explains why and to which purpose such gridded data are useful in a wide range of application areas, such as in disaster response, health interventions, and survey planning. 

Global Human Settlement Layer - Population. (c) JRC

Each year, nearly 160 million people are impacted by disasters. At that time, every second counts to save lives and to ensure that critical supplies reach those in need. Reliable and timely population data linked to location are key, and traditional data sources, such as household surveys and population censuses present a range of geographic, temporal, and logistical challenges. In this respect, gridded population data have emerged as an important resource for delivering actionable data for responding to disasters and monitoring health and infectious diseases. 

Gridded (or raster) population maps represent the distribution of population in rows and columns of grid cells, typically defined by their latitude-longitude coordinates. With recent advancements in Earth observations’ capabilities and statistical methods, it is now possible to obtain more frequent and more granular population estimates worldwide. An increasing number of data providers are combining information from censuses with satellite-derived geospatial features to redistribute populations and produce gridded population datasets. 

These gridded datasets offer a number of benefits:

• They provide informed and timely estimates of population distribution.
• They facilitate direct use with other sources of scientific data that are available in a gridded format.
• In areas where recent censuses have not been performed, they provide a starting point for surveys and needs assessments.

Whereas these innovative data products are now becoming integral to decision-making processes for a number of actors, many officials are still largely unaware of their potential. By profiling and analyzing seven major, global gridded population datasets, this report aims to improve the accessibility and understanding of gridded population datasets for policymakers and other users. The report was written with two overarching questions in mind:

• How can gridded population data supplement current population data sources and support users from the sustainable development community to make timely, informed decisions?
• Which gridded population dataset is the most suitable for a user’s intended use?

Connections with GMES and Africa

A Programme jointly financed by the African Union Commission and the European Commission, the Programme aims to promote the use of EO data to enhance the decision making process with regards to natural resources management. A flagship Programme of the African Union Commission, it is meant to directly contribute to the strategy of the institution with regards to African development in the coming years (The Africa We Want). The gridded population datasets can be employed in most of the GMES and Africa financed Projects. More specifically the MIFMASS Project was deployed by a consortium led by the CSSTE to support disasters preparedness and mitigation. More about the GMES and Africa financed Projects...

AN OVERVIEW OF THE REPORT

INTRODUCTION

• CENSUS CHALLENGES AND OPPORTUNITIES
• THE CENSUS REMAINS CRITICAL

CHAPTER 1: HOW GRIDDED POPULATION DATA ARE BEING USED AROUND THE WORLD

• 1.1 IMMEDIATE APPLICATIONS
• DISASTER RISK ASSESSMENT AND RESPONSE
• HEALTH AND INFECTIOUS DISEASE
• SURVEY PLANNING
• 1.2 MEDIUM-TERM APPLICATIONS
• STUDYING POLICY DECISIONS
• THE SUSTAINABLE DEVELOPMENT GOALS
• TABLE 1: SDGS THAT REQUIRE POPULATION DATA
• 1.3 LONG-TERM APPLICATIONS
• SEA LEVEL RISE
• WATER AVAILABILITY
• 1.4 EXPANDING USES AND UNDERSTANDING THE OPTIONS

CHAPTER 2: GETTING TO KNOW GRIDDED POPULATION DATASETS

• 2.1 VARIATIONS IN MODEL INPUTS
• INPUT DATA
• DATA ADJUSTMENT
• MODELING METHOD
• 2.2 OUTPUT CHARACTERISTIC
• 2.3 REVIEW OF GLOBAL GRIDDED POPULATION DATASETS
• GPWV4
• GRUMP
• GHS-POP
• WPE
• HRSL
• LANDSCAN
• WORLDPOP
• TABLE 2: POPGRID GRIDDED POPULATION DATASET
• METRICS
• 2.4 ALTERNATIVE MODELING APPROACHES
• USE OF NEW DATA SOURCES
• 2.5 FINDING THE RIGHT FIT

CHAPTER 3: INTER-COMPARISON AND VALIDATION OF GRIDDED DATASETS

• 3.1 INTER-COMPARISON
• DESCRIBING DIFFERENCES IN ESTIMATIONS
• IMPACTING OUTCOMES
• ESTIMATING CLIMATE CHANGE IMPACTS
• 3.2 VALIDATION APPROACHES FOR POPULATION
• ESTIMATION
• COMPARING WITH CENSUS DATA
• METHOD COMPARISON
• REGIONAL DIFFERENCES
• THE STRENGTH OF HIGHER RESOLUTION DATA
• ERRORS CHANGE WITH LEVELS OF GEOGRAPHY
• 3.3 ALTERNATIVE VALIDATION DATA
• 3.4 THE NEED FOR ADDITIONAL VALIDATION WORK

CHAPTER 4: DECISION-MAKING GUIDELINES

• 4.1 WHERE PEOPLE ARE AT ANY GIVEN TIME MAKES A DIFFERENCE
• 4.2 BE AWARE OF THE MODELING APPROACH USED TO DISTRIBUTE POPULATION
• 4.3 DEMOGRAPHIC GROUPINGS, INCLUDING AGE AND SEX, ARE IMPORTANT
• 4.4 ANALYSIS ACROSS COUNTRIES IS NOT THAT SIMPLE
• 4.5 IDENTIFY THE TIME PERIODS THAT ARE NEEDED
• 4.6 BE MINDFUL OF THE DIFFERENCES BETWEEN URBAN AND RURAL ESTIMATES
• 4.7 ENVIRONMENTAL FACTORS IMPACT POPULATION DISTRIBUTION
• 4.8 CONSIDER COVARIATES
• 4.9 BE COGNIZANT OF THE COST AND REUSE RIGHTS

ADDRESSING MISCONCEPTIONS

Table 2: Popgrid gridded population dataset metrics

 

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OTHER QUOTED SOURCES OF INTEREST

JRC's GLOBAL HUMAN SETTLEMENT LAYER - POPULATION (GHS-POP)

The European Commission Joint Research Centre (JRC) and CIESIN published the first version of

the Global Human Settlement Layer - Population (GHS-POP) dataset in 2015. The latest release

was in 2019. This dataset combines information from population censuses with satellite-derived

built-up areas to allocate population counts from administrative units to a grid according to the

presence or absence of built-up area in the grid cell. More...

CIESIN's DATA SETS AND MAPS

The Center for International Earth Science Information Network (CIESIN) is a center within the Earth Institute at Columbia University. CIESIN works at the intersection of the social, natural, and information sciences, and specializes in on-line data and information management, spatial data integration and training, and interdisciplinary research related to human interactions in the environment.  In particular, CIESIN hosts a Data Center in NASA's Earth Observing System Data and Information System (EOSDIS) that gives access to numerous data sets and maps related to African Satellite-Derived Environmental Indicators, West Africa Coastal Vulnerability, Population Landscape and Climate Estimates, Global Rural Urban Mapping, etc.  More...