Towards Unified Data Layers

Posted on Thu 27 October 2022 in General

painting A Capriccio of Roman Ruins (1727-1729) by Marco Ricci

The opinions below, as always, are mine alone, and do not represent my employer’s, past or present.

Common Operating Datasets

The work done on Common Operating Datasets (CODs) has been one of the most important advances in information management in humanitarian response in the past 20 years.

Common Operating Datasets are typically country level administrative boundaries and population statistics. They are the basic building blocks of a response. In an emeregency, with hundreds of organizations and government departments working together they provide a common point of reference for geographical representation of areas and population within a country. In countries where there is a UNOCHA presence, they usually take the lead in the publishing of that country’s CODs, in coordination with the relevant government statistics office and relevant partners, revising and updating as-neeeded. CODs are probably the most successful example example of coordination of information management. [footnote link to Andrew Verity recent publication]

but… the purpose of this post is not just to praise the work on CODs, it’s to demonstrate emerging alternatives that overcome many of issues we face with CODs.

So what’s wrong with the CODs?

The CODs are not always available at a level of granularity sufficient for detailed analysis. While admin 0 (national-level), admin 1 (typically provincial-level or similar), and admin 2 (typically district-level or similar) can be expected to present in any response with a UNOCHA presence, there can be less of an assumption of availability for the more granular levels of admin 3, 4 or lower. This presents a challenge as analysis may then be presenting analysis at a coarser level of aggregation that may not effectively capture or show differences in needs, gaps or response that a more granular administrative and population would support.

Admin boundaries are often disputed. While many national boundaries are disputed, to varying degrees [ footnote of how many, from wikipedia] this generally isn’t a huge issue in most humanitarian responses. in comparison to the challenge of different perspectives on sub-national boundaries within countries. This can lead to a situation where, depending of engagement at the national level, or with subnational authorities, different datasets may be needed, top relflect of the differing perspectives of what area or people that are being referred to. For compiling data this means the added complexity of needing to know the context of the data received, to understand the perspectives of the data and the asumptions behind it.

High variation in the area and population that a COD unit is referring to. As mentioned above, the number of admin levels in a country can vary, what varies even greater, is the geographic area that COD units represent across countries. An analysis that may be sufficentlty granular in one country, may need to be at admin 3 or 4 in another to provide a similar analysis. While a typical analysis product may have a geographical area that may be optimal for the type of analysis, quite often this has to first match the closest available admin boundaries and population, assuming all required data is also available for this.

Within a single country this variation in admin unit size can lead to misinterpretation of data when visualizing data. A common example of this is with the use of chloropleth maps. Considering two aspect of visual perception - color and size, chloropleth’s often mislead, showing comparatively larger admin areas more prominently,even though their value (colour) may be the same or less. This mis-use of choropleth graphics probably deserves an article by itself. [footnote showing the km2 area of the largest admin 3 and smallest admin2 from the CODs]

CODs are constantly changing, they are living datasets that periodically need updating to reflect administrative changes and population changes in a country. These administrative changes can mean that data from previous years may no longer be compatible to that which was gathered in different years [footnote Pakistan example of admin 1 changes] Currently the CODs dont have a process for version control, meaning that the changes of each iteration may not be known, meaning that datasets associated with previous COD versions may no longer be compatible, or may require significant data transformations or may contain a number of hiddden assumptions.

Demographics and administrative boundaries are intertwined with politics. Administrative boundaries are, as the name suggests reflect the administrative structure of a country. They are a cartographies manifestation much of our countries historic dynamics,current political dynamics especially in conflict situations can themselves be drivers, or at least contentious within the context. The close link of the geopgraphic and the political in-turn influences any analysis that use them. Even in non, or low-conflict contexts, this can still mean challenges, such as delays in publishing or updating datasets due to bureaucracy or otherwise. [ footnote Idai example]

Introducing H3 and Bing quadkeys

One approach we can use that addresses or sidesteps the problems above to seperate political & administrative with geographic concerns and base our geographic units of analysis on units that are consistent no matter what country, context or period the data is from.

There are many ways other than CODs that can be used to seperate and represent different geographic units, many reach back thousands of years [footnote mandala ] but in the past few years, with the growth in web-based mapping, large scale analytics and the explosion of geo-associated data, some interesting approaches have emegerged that are showing a lot of potential for humanitarian action.


The first of these are Quadkeys an approach to geospatial indexing, developed by Microsoft that divided the world into gridded squares [add footnote of Mercator projection limitation] with the size of each square corresponding to an index level. Each square can be subdivided further through subsequent lower levels, allowing one square to represent over 78,271 m2 at its highest level, or 0.0187 m2 at its lowest level.

The second is H3, a similar concept, using hexagons. Developed by Uber, it provide a base for their vast geospatial analytic needs on car pickups, movements, routing etc. h3geo

Their advantages

These two approaches ovecome many of the drawbacks of the CODs as:

  • the resolution/granularity is set to whatever unit that best suits the analysis, or which best matches the available data.

  • each quadkey/hex remains consistent and are inherently immune to disputes over their boundaries or names.

  • for any given quadkey/hex value, their areas remain consistent and comparable [add footnote explaining limatations/approximations due to CRS],

  • they don’t change; a quadkey of data from 100 years can be compared against a quadkey of data 100 years from now, regardless of any changes in administrative boundaries or naming conventions.

  • they offer a means to sidestep the issue of politics intertwined with geography.

  • they encourage privacy-preserving best practices for data analysis.

Unified data-layer examples

I’ll add the examples and conclude this post shortly. Check back here in a couple of days