Posts tagged ‘Urban Growth Modelling’

Employment density projections

Written July 30th, 2015 by

Group of WorkersA key metric produced from an urban growth model is the future projections of employment/jobs for the region being model. These employment projections normally inform the region’s strategic plan and are often quoted by elected officials.  It is important these employment projections are realistic and the employment density assumptions utilised by the model are well documented.

What determines employment projections is the Workspace Ratios (WSR) for various land uses supported by the model. The Workspace Ratio measures the amount of floor space per Employee/Worker. There are wide disparities in these land use Workspace Ratios. It varies from industry to industry, city regions (i.e. CBD vs outer suburbs), even county to county. Read the rest of this entry »

Time for urban farming in cities to reduce obesity

Written June 26th, 2015 by

Urban FarmingIn 2005 over 40 % of the Earth’s land was given over to agriculture. This is an area of roughly 4.6 billion hectares, about the size of South America.  A further 3.2 to 3.6 billion hectares is being used to raise livestock. By 2050 up to 80% of the earth’s population will live in urban centres. If food is to be produced and consumed in the same inefficient way as is today, we will need further arable farm land the size of Brazil to support this population.

The best farming lands are already cultivated. Further increasing the agricultural land area will come with great environmental consequences, such as: destroying valuable natural ecosystems; water pollution from nutrient run-off; and soil erosion. New agricultural models are required. These models need to use new technology to improve cropping productivity while reducing the use of water and the application of fertilizer and other potentially harmful chemicals. Read the rest of this entry »

High density without occupancy

Written April 9th, 2015 by

High density apartmentsThe article High density housing’s biggest myth by Ross Elliott published on The Pulse, suggests many high-rise apartments recently constructed or being constructed contain numerous apartments that are vacant or not occupied, particularly in the inner city areas. We have observed this trend with high density residential properties when developing urban growth models.  This trend imposes the requirement for urban models to provide for properties in some locations not being fully occupied. In some cases this can be as low as 20% occupancy. These low percentages are normally seen in holiday areas such as the Gold Coast or Sunshine Coast.

With the apartments in these high-rise buildings, Ross suggests “many are vacant: simply locked up and not used by their owners (often overseas buyers)”. Whilst this will be true for some apartments, other apartments are being utilised for short-term accommodation. These apartments are available as serviced apartments or short-term rentals and this type of land use should be accounted for in your urban growth modelling. Read the rest of this entry »

50,000 new dwellings along Parramatta Road

Written December 8th, 2014 by

New Parramatta Rd Urban RenewalThe NSW Government has released the Draft Parramatta Road Urban Renewal Strategy. The Government is aiming for 50,000 new dwellings and 50,000 jobs in the Parramatta Road corridor by 2050. With eight suburbs/precincts targeted for development and jobs growth.

I am always a bit sceptical about claims made by government when comes to population and employment projections. The high level assumptions these claims are based on tend to be very optimistic.  When you start to apply them on the ground there are constraints (such as easements, property frontages and network infrastructure capacity) that apply at a property level and restrict what growth will be achieved. Read the rest of this entry »

China builds more houses in 12 years than there are in all of the U.K.

Written October 7th, 2014 by

chinese megacitiesThe growth rates in this article published by New Republic on Chinese megacities seem quite unbelievable: In 12 Years, China Built More Houses Than There Are In All of the U.K. Take the example of Shenzhen growing to 12 million people in 30 years from a cluster of small fishing villages. This gives a compound growth rate of 20% per year, assuming a starting base of 50,000 people.

To put this into perspective, the urban growth models we are dealing with have a compound growth rate around 2% per year.  To service that low growth rate requires investment of many hundred millions of dollars in network infrastructure projects. To have a growth rate 10 times our rate requires investments into the billions of dollars and that is just for one megacity. The article suggests there are at least 6 megacities and 160 cities with populations of more than a million. That is a staggering amount of infrastructure investment required to service that population growth. Read the rest of this entry »

Weather and urban growth modelling

Written September 2nd, 2014 by

Gavin Schmidt presenting at TEDI came across this TED talk by Gavin Schmidt. He is a NASA climate expert and his presentation was about weather models and climate models. In his talk, Gavin explains why we can be confident about predicting how the climate will react into the long-term future.

He discusses the enormous complexities of modelling climate patterns that span a range of 14 orders of magnitude across both time and space. I though modelling urban growth was complex! We are only dealing with 2 orders of magnitude. Even at that level, there is a large body of work required to build and test an urban growth model. I certainly appreciate the mammoth effort needed to build climate models at those scales of magnitude and complexity. Read the rest of this entry »

How to establish a baseline

Written July 7th, 2014 by

Baseline image

The baseline is the most important element of an urban growth model.  Actually, this statement applies to any model. The baseline establishes the reference point from which a model will forecast future growth.  Not having an accurate baseline will result in your model either over or under allocating urban growth, especially in the early projection year cohorts.

Normally your baseline can be derived from the existing land uses of cadastral land parcels within the area that is subject to the urban growth model.  You might think establishing a baseline for a large cadastral model is a very challenging task.  Actually with today’s digital geospatial tools it is relatively easy. Although it is still time-consuming.

So how do you go about creating a baseline? Read the rest of this entry »