Due to the lack of publicly available information on publicly owned land within the Cape Town Municipality, it became necessary for us to develop a methodology to build a database ourselves. The aim of this database was to more fully understand how much public land each sphere of government owns that is vacant and underutilised. The idea is that by demonstrating how much public land is available for social good such as the development of housing, all three spheres of government will no longer be able to perpetuate the myth that there is a shortage of land that can be used to address the housing crisis. While not entirely accurate, this map is based on the most accurate publically available data. The map aims to provide an overall picture of the vast amount of vacant and underutilised public land at a moment in time. The data collection for this map was done between 2018 and 2022.

This methodology entailed a desktop study that used a visual assessment of publicly available aerial imagery of land that appears to be vacant or underutilised. Once seemingly vacant or underutilised land was identified, we used the City of Cape Town's online tools to establish ownership and further details of individual sites. Wherever possible we made use of the City of Cape Town’s own online tools to identify property owners on the understanding that as the municipality, they should have the most accurate data on public land within their boundaries. This also means that all data used already exists in the public realm.

Public land is publicly owned and by extension belongs to all of us. However, despite our best efforts to access information on public land through formal requests to the City of Cape Town, this data is generally inaccessible to the general public. Either the data is located in different formats across multiple digital platforms or the ownership information is not readily available. We aim to bring public land into the public domain. This map is not a tool to encourage land occupations or speculation by the private sector, but is rather a tool to promote accountability and stimulate the public imagination.

Layer 1: Vacant and Underutilised public land

Step 1: Visually identifying vacant or underutilised sites

Firstly, as a proxy for vacant and underutilised land we would do a systematic visual search, area by area, on both Google Maps and the City of Cape Town’s City Map and Zoning Viewer for sites that appear from a birds eye view to be vacant or underutilised. We made use of a list of suburbs and used roads and other physical structuring elements of each area to ensure that areas were visually surveyed meticulously. The City Map and Zoning Viewer is publically available through the City of Cape Town’s Planning Portal and provides spatial details across the metro. For the City’s own description of the tool see: here.

On the City Map and Zoning Viewer we used the latest aerial photography layer, which was from 2018 when this process began. Google Maps has updated their aerial photography over the years that we have been collecting this data, with the aerial photography being from 2021 at the time of launching this map. Because land ownership changes over time and public land will continue to be bought and sold once we launch this map, this map provides a look into public land ownership during the period of time that we have been creating this map, i.e. 2018 - 2022.

Determining what is ‘vacant or underutilised’ from aerial photography alone is a subjective assessment of a piece of land. A clear limitation of this approach is that these sites have not been ground-checked. Furthermore no analysis of government planning documents have been done to assess whether any specific site identified is currently leased out by government or has been earmarked or reserved by government for specific use and/or delivery. Very limited analysis has been done on the commitment of well-located sites for affordable housing. This means that we have collected this data on the basis of what appears vacant and underutilised from a bird's eye perspective to provide a city-wide overview of the extent of public land that could be used better. It would be necessary for any map-user to conduct their own ground level assessment and assessment of government planning documents should they wish to get a more complete, accurate and deeper understanding of any specific site.

Please note that for capacity reasons the areas of Parow, Belhar, Milnerton, Elsies River, Kuils River, Delft and Blouberg have only been partially mapped. This means that the map provides a conservative estimate of public land. This is only the first iteration of the map, and we hope to more fully survey these areas in future versions.

It is also worth noting that the current version of the map does not attribute environmentally sensitive land parcels, and that this is another reason why some of the land on the map may not be suitable for development. We have endeavoured to avoid including land parcels that are clearly environmentally sensitive or inappropriate for development.

The criteria used to identify vacant and underutilised land is as follows:

1. Visual assessment of land with unrealised potential:

We looked visually on the aerial photography of an area for sites that were not at all, or not entirely built up. We have included parking lots, open land, golf courses, schools with large grounds and other sports grounds in this assessment.

This does not mean that we think that affordable housing should be built on all available open or green space across the city. Rather, when looked at holistically it is clear that the state is not making use of the well-located land that it owns in an equitable and efficient way that balances the pressing demand for affordable housing with the need for open green space and uses for public good. The need to look not just to empty but also to partially used public land is in line with a growing need for underutilised public land that is used for schools, parks and more to be intensified and used to its full potential. For instance, the African Centre for Cities has called for portions of neglected and underutilised school grounds to be used for infill development of affordable housing as a way of densifying, activating an increasing safety of the area while providing inclusive housing opportunities.

As it is near impossible to establish from aerial imagery whether a building, rather than a piece of land, is vacant or underutilised, this means that there are many sites that in reality stand vacant and underutilised that are not included in this database, making it a conservative estimate.

2. Size:

We have only included sites that are over roughly 1000m² that appear from the aerial imagery to be vacant or underutilised. This is due to the fact that it is highly unlikely that it would be feasible to develop affordable housing on a site smaller than this. This means that this map does not capture all vacant and underutilised public land and is therefore a conservative estimate.

Step 2: Establishing whether the vacant or underutilised site is publicly owned

Once a site was visually identified as vacant or underutilised, we established whether the land is publicly owned. In order to do this, we referred back to the City of Cape Town’s City Map and Zoning Viewer to establish the erf number and/or address. We used this information to search for the ownership of the site by searching the erf number or address on the latest publicly available General Valuations Roll, from 2018. This is used as it is the most recent record of municipal valuations for Cape Town that is publicly available. Where we cannot establish ownership on the 2018 General Valuations Roll due to missing or incomplete data, we have in some instances used the 2015 General Valuations Roll or an online property platform to confirm ownership.

Step 3: Recording publicly owned vacant or underutilised land

Once we have established that a site is both visually vacant or underutilised and publicly owned, we then record the details of that site in our database. We include in our database additional information from both the City Map and Zoning Viewer and the General Valuations Roll including the size, zoning and value of the site. We have often had to group multiple erven together into one piece of land when they could functionally form an individual site. Ideally, the City would be consolidating these parcels of land itself in order to maximise their potential.

Step 4: Tracking progress of mapping

As a final step in the data collection process, we have created a Google Map to track the public land we’ve captured as we go. The primary purpose of this was to increase accuracy by helping us to gauge our progress and make sure we had mapped systematically across the city and had not missed any suburbs or areas. This included capturing sites that were privately owned to ensure efficiency and avoid the re-checking of sites. This step also created a proto-type map that assisted in our imagining and thinking around the final public land map output.

Layer 2: Well-located public land committed for affordable housing

As mentioned above an assessment of government planning documents has not been done as part of this work. However, a layer has been developed on the map which includes notable commitments for affordable housing in well-located areas by various spheres of government. News outlets as well as government documents, speeches and media statements were used to provide the most accurate publicly available information about these commitments including what the commitment was and the status of that commitment.

For instance, for the 11 Woodstock, Salt River and Inner City Precinct Affordable Housing Prospectus Sites announced by the City in 2017, we collected information about the sites and what was planned for them in the City’s Woodstock, Salt River and Inner City Precinct Affordable Housing Prospectus document and since then have used the City’s media statements, public participation processes and public forums to collect information on the progress on the commitments.

The City Map and Zoning Viewer and the General Valuations Roll were used to supplement additional information about the various sites including the size, zoning and value.

Progress on these commitments made after the launch of this map will not be updated. This means that what you are looking at is a moment in time and some additional progress may have been made on these promises by the time you are seeing this.

Creating the online interactive map

In collaboration with OpenUp, Civic Technology & Open Data Specialists, the spatial data of the two layers was then overlaid over a basemap and translated into the online interactive map that you are using today!