Step 1: Data collection

Data collection is the first step of the SCA.

Goal: Collect almost all the necessary data first, before processing it in any way.

Situation: By beginning the SCA, you are starting to find out what kind of data you need and where which of it can be found. You need to organise it all first. The reason for doing all the data collection in one step, is to assess completeness of data for the sector and therefore also identify gaps. (These can then be filled with downscaling calculations in Step 2 - Data processing.) The more comprehensive and accurate the data, the better the potential for a good understanding of the sector and circularity assessment.


Collect data and (1) organise them in folders on your desktop or (2) upload them to the CityLoops Data Hub, with the help of Layers.

Data collection structure

To make it easier to follow what is needed, and understand what themes certain datasets belong to, the data collection was structured in “Layers”. (These are also set up as such in the CityLoops Data Hub, see in Bodø, for example.) There are three distinct layers:

Data types

You need to collect two types of data, namely numerical data (those in spreadsheets) and spatial data (e.g. maps and points on maps that come from geospatial spreadsheets and so-called shapefiles).

Collecting data

  • Own local data: Cities have their own economic data and local waste management companies, regional and national statistical offices, urban/provincial/state administrations etc. have even more available data.
  • Other existing data: A great deal of these existing datasets and data portals is already available on the internet. All of this data can be used, but finding, collecting and cataloguing a city's data correctly (for future use), is the more challenging part.
    • The Metabolism of Cities community has been collecting and cataloguing datasets on the Metabolism of Cities Data Hub in the “Library section” and the data portals in the Metabolism of Cities Library. The items are listed with a brief description and meta information.
    • Especially noteworthy is a special group of existing datasets, the ones from Eurostat. There are 8,037 unique datasets across a wide range of themes. Metabolism of Cities has already reviewed, identified and tagged the relevant ones and put them in the “Eurostat grid” (see respective handbook section).
  • NO primary data: There is already a lot of existing data, hence in principle, there is no need to generate or collect primary data.