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Why map empty space?

23 May 2017

How can cities assess the potential of vacancies and spaces suitable for temporary use?

Fanis Kafantaris, Speleo, Athens Biennale

By Irīna Miķelsone (City of Riga, LV), Mārcis Rubenis (Free Riga, LV)

How do you tackle and move forward on issues that are invisible? This is the trouble with urban vacancy. It is often the case that there is a considerable number of vacant buildings in a city, but, without a clear overview of the situation, the true scale, impact and potential of these vacancies and temporary-use spaces remains unclear; they may as well be invisible.

Is your city in need of more affordable housing or properties for public or commercial use? Or are vacant and degrading buildings a pressing issue? Mapping or visualising vacancy is the first step towards making the challenge visible and framing temporary use as a possible solution for revitalisation, socialisation and the maintenance of vacant buildings.
This guide will walk you through the relevant questions in establishing the right approach to mapping vacancy. Keep an eye on our blog for a series of case studies from REFILL’s partner cities.
Leerstandsmelder Bremen

Screenshot of the Leerstandsmelder tool showing an overview of vacancies in Bremen

From the experience of REFILL cities and other cases known to us, one can observe three stages a city goes through in mapping vacancy. First, data is collected on the city’s vacant properties; second, the public is engaged with to gather ideas, assess needs and raise awareness of the vacancies; and third, the city facilitates the forging of connections to be used in mediating temporary use.

Why map empty space?

To start with, mapping is useful when vacancies are not visible and there is not enough information to understand their impact on the city. In the following three cases this issue has been addressed with the use of collaborative online mapping tools: in Riga (Latvia), in Bremen (Germany), with its Leerstandsmelder (‘vacancy indicator’) tool and across the whole of the Czech Republic with Prazdne Domy. In all of these cases, any user can submit a report about a vacant building and thus help to create a more comprehensive overview of vacancy in each city or region. These tools focus on making it easy for users to submit vacancy reports.
What about when the vacancies are already known but public engagement (for generating ideas for use, sourcing relevant existing knowledge and raising support) is lacking? Then other, more engaging approaches to mapping can be useful. Such as in the case of the Speleo workshops and walking tours in Athens (Greece), which help to simultaneously map vacancy, raise awareness and promote useful discussion. In Riga (Latvia), provocative ‘Occupy Me’ stickers are used to mark empty buildings as part of a campaign that engages a broader public. In Helsinki (Finland), the online map-based survey tool Maptionnaire is used, helping the city to source information from citizens about the kinds of public spaces they’d like to see replace the vacant properties in their neighbourhoods.
All of these tools are more engaging and thus require deeper participation from users. As such, the number of users tends to be smaller. However, their impact can be essential in raising awareness and potentially in gaining media attention and gathering greater support when launching subsequent initiatives.
The final stage is the city’s search for ways to facilitate connections between available vacant spaces and initiatives. For example, Helsinki is experimenting with a space reservation system that makes use of public data on vacant city-owned property. This system has already enabled 8,000 reservations of municipal property. In the Netherlands, the city of Amersfoort engaged in a matchmaking initiative by creating an online map that uses information on existing and planned sustainable food initiatives to forge connections with city properties that could be used by such initiatives. The Dutch city of Groningen has created an online platform that maps both municipal and private property (including land) available for temporary use and invites prospective users to submit applications for its use.
Occupy Me by Free Riga, Latvia © Janis Peshiks
‘Occupy me’ campaign by Free Riga, Latvia © Janis Peshiks 

How to map? Online or offline, formal or informal, presentational or collaborative?

Another decision for cities to make is whether to go with online or offline mapping. Offline mapping activities can be deeply engaging, capturing citizens’ imaginations and raising awareness on the issue in a way that a purely online campaign could not. This is demonstrated by Riga’s ‘Occupy Me’ campaign that saw 5,000 stickers quickly finding their way to empty houses, promoting public discussions similar to those sparked by the Speleo workshops and ‘walkshops’ in Athens.
In Riga, offline activities were found to be a good way to encourage new participants to join the initial interest group, to kick-start public discussion and establish the parameters for online mapping. However, municipalities considering such activities should bear in mind that such sticker campaigns and walkshops require a degree of informality, grass-roots spirit and a network of organisers. Look for informal architect or activist groups eager to contribute to the topic of vacancy and temporary use who are ready to experiment with activities that might not always be strictly legal but which are likely to resonate, such as with the stickers.
Online mapping, on the other hand – as showcased especially by the Bremen collaborative mapping example – has the potential to reach much larger audiences. This is provided that the topic is already on the public agenda and people understand its importance. Online mapping has several advantages: it can deliver results for an extended period of time, produce quality data (giving an overview of the vacancies across the whole city), and potentially engage more diverse and harder-to-reach groups of citizens.
When considering the options for mapping vacancy it is also essential to explore levels of interaction and engagement. In some cases, a municipality may opt for a purely presentational solution, like Amersfoort’s urban agriculture map, while in other cases collaborative solutions might provide valuable additional knowledge about vacant properties, as in the case of Bremen’s Leerstandsmelder, where people can not only submit vacancy reports but also add comments to every report.

What to map? General vacancy, topic-related vacancy or societal needs?

A good first step is for cities to map all types of vacant property. This helps to raise awareness of the scope of the problem and to gain data on which to act. Mapping topic-related vacancies, on the other hand, serves as a way to focus on specific issues related to vacancy and to start connecting people around this topic to find a specific solution. Such was the case in Amersfoort where the city focused on mapping sustainable food spaces and initiatives to raise awareness of the need for more sustainable food in the city, or in Helsinki, where Maptionnaire mapped the citizens’ needs: spaces for co-working, hobbies and leisure. This information could then be used by the city to inform the subsequent planning process. 
While a primary layer of data forms the basis for any map or visualisation, a secondary layer of data is important for giving more meaning to the map; it inspires action and provides additional perspectives on vacancy. Groningen, for example, with its Ruimte in de Stad initiative, mapped not only available vacant buildings and their possible temporary-use period, but also showcased previously successful temporary use projects. In Riga’s online mapping project, not only vacant buildings were mapped, but also public-, bank- and privately-owned properties, each ownership group highlighted with a different coloured pin on the map.


Mapping is a key element in raising awareness and connecting people around the topic of vacancy. It showcases both the problems and the potential of vacancy and should be considered as one of the first steps for any municipality seeking to address this issue. Before designing a mapping tool or campaign it is important for a municipality to explore its aims or the ‘whys’ of the mapping (gathering data, engaging with the public, ‘matchmaking’, etc.); the forms or the ‘hows’ of mapping (online, offline, formal or informal, presentational or collaborative tools); as well as the object or ‘whats’ of mapping (general vacancy, specific topic-related vacancy and the needs or ideas of citizens).