Median Household Income in the City of Toronto

This map shows the median household income of every Census Dissemination Area in Toronto, based on the 2011 National Household Survey collected by Statistics Canada. This is the smallest unit these data are reported on, and are only available to me as a graduate student at Ryerson. I accessed these data via the excellent University of Toronto CHASS research site.





I realize these data have their limitations including sampling bias and small geographic unit sample size, but I still think it is interesting to see the overall patterns. I was inspired to review these data after a recent graduate class discussion about the "Three Cities of Toronto" project by Dr. David Hulchanski at the University of Toronto. His work involved mapping real income change between 1970 and 2005, not only a single year as shown above.

UPDATE: I have added one more map below showing Median Household Value. These data appear to have much more spatial clustering, with significant division between the central area and out suburbs.

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Public Park Accessibility in the City of Vancouver

I am very happy that Vision Vancouver Councillor Reimer tabled a notice of motion yesterday called "Protecting Vancouver’s Public Green Space" which included the following statement:

"The Greenest City Action Plan adopted by Council in 2011 sets a target that every person in Vancouver lives within a five-minute walk (400 metres) of a park, greenway or other public green space by 2020"

My first thought when reading this was simple: how will this indicator be measured? Specifically, I recalled a recent diagram in the Oakridge rezoning application slides (a project I fully support, just for the record) that shows 400 metre buffers from surrounding parks:



The trouble with this diagram is the 400 metre buffers appear to originate from the park centroids. Alternatively, I beleive 'accessibility' has actually been measured based on a buffer from the outer edge of parks. In other words, if I leave my house and walk 400 metres and arrive at the edge of a park, I would consider it to be accessible. I decided to explore these two interpretations; the following map shows the area within a 400 metre buffer of park 'centroids' in medium green, and the area within a 400m buffer from park 'areas' in lighter green:



In addition, I also clipped each 2011 Census Dissemination Block to the 400 metre buffer from the edge of parks, and calculated the fraction of each block that was within the threshhold. The fraction of the area was then used to calculate a proportion of the population per block that has no park accessibility. For example if a block had 100 people and it was 75% within the buffer zone, 25 people were considered to have no access to a park. As a result of this analysis, I determined that 79,407 people or 13.2% of the population of the City of Vancouver live greater than 400 metres from the edge of a public park. These people are shown using the yellow proportional symbols in the map below:



I also reviewed the Greenest City progress report and noted the indicator the City has selected is significantly simpler.Their indicator is "Percent of city's land base within a five-minute walk to a green space". In other words their target is based on area instead of population. Which is fully valid, but I still wonder how if they are measuring their covered area based on buffers from the park centroids (as shown on the Oarkridge map) or from outer edge of the parks (which would yield a larger total covered area and I am fairly confident this has been done). At the end of the day, I do not mean to criticize the outstanding work the City is doing, I am simply trying to highlight how an oversimplified diagram can lead to ambiguous results.

I am excited to learn more about this motion as it is developed because I have been working on many projects related to this theme at Golder Associates Sustainable Communities Group over the past few months. For example, I have conducted extensive GIS analysis and visualization to support the City of Vancouver's ongoing Integrated Stormwater Management Plan (ISMP)and the John Hendry (Trout Lake) Park Master Plan.

I understand this Notice of Motion is referencing much more area than just parks, and exactly what should be considered 'greenspace' will likely be a topic for a future post. For example, community gardens and greenways are referenced in the Greenest City action plan as features that satisfy the 'greenspace accessibility' target. Alternatively, given my recent focus on stormwater management I would also suggest it may be equally important for the City to implement a 'no net loss of pervious surfaces' target to maximize onsite infiltration of rainwater.

I hope this post shows that GIS tools are not always as objective as they appear and it is important for policy makers to consider how various calculation methods can impact progress towards targets.

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2014 Vancouver City-Wide Property Values

Last week the City of Vancouver was named the second most expensive city in the world - again. Sadly, this study only evaluated the median cost of single family homes in Metro Vancouver relative to average income. This is hardly a comprehensive portrait of housing affordability. In the same week, I was excited to see Andrew Yan's latest annual map of single-family property values in Vancouver. However, given the fact that only 33% of dwellings in the city of Vancouver are single family homes, this year I wanted to know more.

Over the past two years, I have utilized BC Assessment data extensively for many urban planning projects completed by Golder's  Sustainable Communities Group (formerly HB Lanarc). Given my somewhat specialized expertise mapping this complicated data, I felt compelled to visualize the Open Data on land values with a fresh perspective.

Below is my map of total property values for every parcel in the City of Vancouver. Note that the values for strata properties are shown as the aggregate value of all properties. Additionally, I have not shown the value of land within parks. Finally, the 'million-dollar line' is clearly visible at Ontario Street. I know this is a lot to absorb but I hope you will find many interesting nuggets of insight on this new city-wide map. For example you can see there is a light-red rectangular area around Shaugnessy where all parcels are over $2,000,000, except along the arterial roadways where parcels are less expensive.



As a professional cartographer, it is also my moral duty to standardize the property values by parcel size to control for the fact that many west-side properties have larger lots. This calculation is the total assessed value of each parcel, divided by the total area of each parcel in sq. m. This important analysis reveals a very different visual story - the light-red rectangle in Shaugnessy is no longer obvious after the data are adjusted.



You can also compare these two maps by looking at the animaged GIF image below:





To understand how land uses and population patterns are related to property values, I encourage you to also review the city-wide zoning map and population density maps. Please note the zoning map shows aggregated categories not actual zoning codes, as there are over 500 specific zones within the City of Vancouver. Additionally, the chart below shows the average value per sq. m. for land within each of the zoning categories.

If you would like to learn more about this project, please contact me. As a local leader in spatial analysis and cartography, Golder would be happy to assist you in developing custom applications using these data. For example mapping 2013-2014 property value changes may reveal several surprising local trends, despite the fact there was an average appreciation of only 2% on average last year. The ratio of land value and improvement values could also be evaluated to identify specific parcels that may be most suitable for redevelopment.

I hope this map fuels a conversation about economic facts so that we can create a healthier, more inclusive city. Please ask any questions that come time mind using the form below or subscribe to my blog to receive updates in the future.


UPDATE: CLICK HERE TO SEE A NEW MAP OF PROPERTY VALUE CHANGES BETWEEN 2013-2014.

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Vancouver: The Quest for a Perfect Land Use Map

The art of cartography is a skillful balance of context and clarity. I am curious what you think should be added, changed or removed to this design?

For some context, below is the City's own land use map, adapted slightly from here: http://vancouver.ca/files/cov/Zoning-Map-Vancouver.pdf

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