Assessing urban agriculture potentiality in the City of Edmonton
By Yichun Du
Geovisualization Project, @RyersonGeo, SA8905, Fall 2020
North America is one of the most urbanized areas in the world, according to the United Nations, there are about 82% of the population living in the cities today. It brings various issues, one of them is the sustainability of food supply. Currently, the foods we consume are usually shipped domestically and internationally. Only a few of them are locally supplied. It is neither sustainable nor environmentally-friendly, as a large amount of energy is burned through the logistics of the food supply chain. In order to address this issue, many cities are introducing and encouraging urban agriculture to citizens.
Urban agriculture is usually summarized as food production activities occurred in urban areas (Colasanti et al. 2012). Zezza & Tasciotti (2010) identified that urban farming and related sectors have employment of around 200 million workforces, and it provides food products to more than 800 million residents. Also, urban agriculture can bring benefits to the city in the aspects of economics, social, citizen health, and ecology. Besides, implementing urban agriculture can help the city to reinvent itself in an attracting, sustainable, and liveable way.
The City of Edmonton is North America’s northernmost city (at about 52.5° N) with a population of 0.932 million (2016 Census). However, apart from some very general municipal strategies (a general vision for food and urban agriculture in The Way We Grow MDP, and a more detailed document fresh: Edmonton’s Food & Urban Agriculture Strategy introduced in 2012), there is very little study on the urban agriculture suitability for the City of Edmonton. which gives the incentive to develop this study. The Geo-Visualization of the outcome can inform Edmontonians where to sow the seeds, and also tell them that the place they live has great potential in growing food.
Edmonton is located on the Canadian Prairie, which leads to very minor topographic changes in the city, but very cold and snowy winters. It limits food production in snow-free seasons, but provides flat ground for agriculture. To conduct an assessment of urban agriculture potentiality for the city, I focused on two themes: ground and rooftop.
The ground part is for assessing the potentiality of food production directly taking place on the ground, including the backyard of a house. The general concept is to utilize the existing land-use that supports urban agriculture activities, however, it should be far away from pollution, and to avoid negative externalities. That is to say, current agriculture zoning, parkland, and vacant lots are favoured. Top-up on that, soil nutrient level will be taken into consideration. Then, the constraints will be the close distance to the source of pollution. Meanwhile, urban agriculture activities can bring potential contaminations, such as water pollutants to the water bodies. So the activity should be at a distance to water bodies.
The rooftop part is for assessing places such as the rooftop of a large building, balconies of a suite in a condo building, or any other places in an artificial structure. The goal of implementing urban agriculture at rooftops is to encourage people to participate, and to focus on proximity to markets, which is people’s dining tables. However, pollution from the surrounding environment should be avoided.
The project will present the scores at the neighbourhood level in both themes of Ground and Rooftop that shows the potentiality of urban agriculture in the City of Edmonton.
Based on the general concepts mentioned above, the following data are chosen for conducting the analysis. Majority of the data are retrieved from the City of Edmonton’s Open Data Portal. The waterbody shapefile is obtained from the Boundary files at Stats Canada’s 2016 Census.
- Urban Primary Land Vegetation Inventory
- Road Networks: Single Line Street Network
- City of Edmonton – Rooflines
- City of Edmonton – Zoning Bylaw Map
- Drainage – Storm Water Management
- Lakes and rivers
- City of Edmonton: Neighbourhood Boundaries
The preliminary part of this project is done at ArcMap. Then, the visualization part is proceeded using Tableau.
The general methodology can be summarized in the following workflows. The first workflow below is for the Ground potentiality. Majority of the work was done on ArcMap. After that, the final results were brought to Tableau for Geo-Visualization with the Rooftop part. The blue boxes are for presenting the original shapefiles. The Yellow boxes are for the Data Criteria. The pink boxes are displaying the secondary shapefiles that are constraints, the green boxes are showing the potential areas or the final results. Both of the pink and green boxes are generated through the white boxes (geoprocessing steps). The final results are processed with data normalization, and an average score was given. So the total score in one neighbourhood was normalized by the total area.
The second part is the Rooftop potentiality. It has a similar process of the Ground part in getting the results.
Also, a table for the weighting scheme of all the selected criteria is shown below. Constraints are assigned with a negative value, while potentials are assigned positive values. Also, the weights will be heavier for more constraints or potentials.
Larger the number, higher the potential for conducting urban agriculture. The Ground has a maximum score of 3.8, while Rooftop has a maximum score of 4 in this analysis.
The results of the scatter plot below suggest that the majority of the neighbourhoods in Edmonton have the potential for urban agriculture. For the Ground theme, only a few of the industrial zones have a score of 0. All types of neighbourhoods are widespread in the score classes. However, the River valley System tends to be associated with medium to high scores. For the Rooftop theme, more than half of the neighbourhoods are in medium to high scores (>2) for the potentiality. Nearly all the mature neighbourhoods are associated with scores higher than 3. Only a few transportation and developing land-uses are having scores of 0.
The next screenshot is the final output from the Tableau Dashboard. Audiences can click on any of the elements that represent a neighbourhood for an excluded view of that specific neighbourhood. For example, you can click one neighbourhood on the Ground map, then the same neighbourhood will be highlighted in the Rooftop map, as well as the point representing that neighbourhood in the scatterplot will be zoomed in with the corresponding score in the two themes. On the other hand, the Audience can select the point in the scatterplot, and the neighbourhood will be zoomed in in the two maps. Also, the audience can view the typology of the neighbourhood and figure out the associated scores for each typology of the neighbourhood by selecting the typology in the legend. Then, all the neighbourhoods belong to that typology will be displayed in the three views.
Tableau provides an interactive visualization of the urban agriculture potentiality in Edmonton at the neighbourhood level. Please click here for viewing the project.
For example, I clicked Oliver neighborhood for Ground score (1.270), then the associated Rooftop score (2.010) and the detailed location of Oliver Neighbourhood is shown in the Rooftop view. Also, the scatterplot for both scores is provided below, with the neighbourhood typology of Central Core.
There are some limitations regarding this project’s data source and methodology. If I have access to updated soil nutrition data, solar radiation data, precipitation data that related to the Ground theme, then I would have a better assessment model for a more ideal result regarding the potentiality of the Ground. Also, an inventory of the physical surface details can help to determine where the impermeable surfaces are. Similarly, if I have a comprehensive dataset of rooftop types, including the slope of the roofs and the individual use of the building, could help to eliminate the unsuitable roofs. Moreover, detailed zoning shapefile with potential land-use modification of community gardens, or backyard gardens would be beneficial to the future application of this project. As for the methodology improvement, the major concern is the weight assignments. Opinions from local experts or the authority can help to improve the model to fit the local context. Also, public consultation or survey can bring the general public to the project, which can form a bottom-up approach in transforming Edmonton into an urban agriculture-friendly place. As an expectation for the future development of this Geo-Visualization project, I would like to see more inputs in data source, as well as participation from the general public and local authorities.
To sum up, this assessment of urban agriculture potentiality in the City of Edmonton assigns all the neighbourhoods scores for Ground and Rooftop potentiality. With those scores, a perception is provided to Edmontonians on where to sow the seeds on the ground, and which neighbourhoods are in the best locations for urban agriculture.
Colasanti KJA, Hamm MW, Litjens CM. 2012. The City as an “Agricultural Powerhouse”? Perspectives on Expanding Urban Agriculture from Detroit, Michigan. Urban Geography. 33(3):348–369. doi:10.2747/0272-3618.104.22.1688
Zezza A, Tasciotti L. 2010. Urban agriculture, poverty, and food security: Empirical evidence from a sample of developing countries. Food Policy. 35(4):265–273. doi:10.1016/j.foodpol.2010.04.007