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Urban Development

What can satellite imagery tell us about secondary cities? (Part 2/2)

Sarah Elizabeth Antos's picture
In the previous blog, we discussed how remote sensing techniques could be used to map and inform policymaking in secondary cities, with a practical application in 10 Central American cities. In this post, we dive deeper into the caveats and considerations when replicating these data and methods in their cities.

Can we rely only on satellite? How accurate are these results?

It is standard practice in classification studies (particularly academic ones) to assess accuracy from behind a computer. Analysts traditionally pick a random selection of points and visually inspect the classified output with the raw imagery. However, these maps are meant to be left in the hands of local governments, and not published in academic journals.

So, it’s important to learn how well the resulting maps reflect the reality on the ground.

Having used the algorithm to classify land cover in 10 secondary cities in Central America, we were determined to learn if the buildings identified by the algorithm were in fact ‘industrial’ or ‘residential’. So the team packed their bags for San Isidro, Costa Rica and Santa Ana, El Salvador.

Upon arrival, each city was divided up into 100x100 meter blocks. Focusing primarily on the built-up environment, roughly 50 of those blocks were picked for validation. The image below shows the city of San Isidro with a 2km buffer circling around its central business district. The black boxes represent the validation sites the team visited.
 
Land Cover validation: A sample of 100m blocks that were picked to visit in San Isidro, Costa Rica. At each site, the semi-automated land cover classification map was compared to what the team observed on the ground using laptops and the Waypoint mobile app (available for Android and iOS).

What can satellite imagery tell us about secondary cities? (Part 1/2)

Sarah Elizabeth Antos's picture

The buzz around satellite imagery over the past few years has grown increasingly loud. Google Earth, drones, and microsatellites have grabbed headlines and slashed price tags. Urban planners are increasingly turning to remotely sensed data to better understand their city.

But just because we now have access to a wealth of high resolution images of a city does not mean we suddenly have insight into how that city functions.

The question remains: How can we efficiently transform big data into valuable products that help urban planners?

In an effort a few years ago to map slums, the World Bank adopted an algorithm to create land cover classification layers in large African cities using very high resolution imagery (50cm). Building on the results and lessons learned, the team saw an opportunity in applying these methods to secondary cities in Latin America & the Caribbean (LAC), where data availability challenges were deep and urbanization pressures large. Several Latin American countries including Argentina, Bolivia, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, and Panama were faced with questions about the internal structure of secondary cities and had no data on hand to answer such questions.

A limited budget and a tight timeline pushed the team to assess the possibility of using lower resolution images compared to those that had been used for large African cities. Hence, the team embarked in the project to better understand the spatial layout of secondary cities by purchasing 1.5 meter SPOT6/7 imagery and using a semi-automated classification approach to determine what types of land cover could be successfully detected.

Originally developed by Graesser et al 2012 this approach trains (open source) algorithm to leverage both the spectral and texture elements of an image to identify such things as industrial parks, tightly packed small rooftops, vegetation, bare soil etc.

What do the maps look like? The figure below shows the results of a classification in Chinandega, Nicaragua. On the left hand side is the raw imagery and the resulting land cover map (i.e. classified layer) on the right. The land highlighted by purple shows the commercial and industrial buildings, while neighborhoods composed of smaller, possibly lower quality houses are shown in red, and neighborhoods with slightly larger more organized houses have been colored yellow. Lastly, vegetation is shown as green; bare soil, beige; and roads, gray.

Want to explore our maps? Download our data here. Click here for an interactive land cover map of La Ceiba.

Helping Brazil realize its infrastructure promise

Paul Procee's picture


Photo: LWYang | Flickr Creative Commons

Since the 1980s, investment in Brazil’s infrastructure has declined from 5% to a little above 2% of the country’s Gross Domestic Product (GDP), scarcely enough to cover depreciation and far below that of most middle-income countries (see figure below). The result is a substantial infrastructure gap. Over the same period, Brazil has struggled with stagnant productivity growth. The poor status of infrastructure is broadly believed to be a key reason for Brazil’s growth malaise.

Trinidad from space: using satellite imagery for better urban management

Ana I. Aguilera's picture
Foto aérea de Trinidad, Bolivia. / Banco Mundial.

The first time I heard of the Bolivian city of Trinidad was exactly 11 months ago. Although Trinidad is the 10th largest city in Bolivia, I confess I did not know much about it. The Ministry of Development Planning (MPD) had commissioned the World Bank a study on intermediate cities in Bolivia, and in my early research I learned that this was a colonial city founded in 1686 during Jesuitic Missions. Similar in its architecture and climate to the southeastern cities of my native Venezuela, Trinidad is extremely vulnerable to flooding that affect thousands of families and businesses each year.

Ranking the world’s megacities is a wake-up call for women’s rights

Monique Villa's picture
Cities are becoming monsters. Look at the world’s biggest megacities. 38 million people live in Tokyo! Try to take a taxi and find the house of a friend in Japan’s capital. You need luck. Six billion people will live in cities by 2045.

Cities are the new states; today, many of the world’s 31 megacities have larger populations and economies than individual nations.

For many people, these big urban centers represent the land of opportunity, offering better chances of employment, increased access to education and health services, social mobility.  For many others it’s a daily struggle for survival. In all big cities, the inequality between rich and poor has become gigantic and the divide seems only to grow.

We conducted a poll to investigate one aspect: how do women perceive their life in the world’s megacities? We chose women because they are the real economic accelerators, re-investing 90% of their salary into their families. When a woman thrives, her immediate community thrives with her.

Throughout June and July, we asked 380 gender experts in the 19 countries hosting the world’s biggest megacities to identify in which they thought women fared best and worst. The findings were eye-opening. They returned a truly compelling snapshot of the wider issues faced by women: from sexual violence, to security, to access to reproductive rights, from the risks of harmful cultural practices, to the lack of access to economic opportunities.

London was voted the world’s most female-friendly metropolis, thanks to its provision of free healthcare and access to economic resources such as education and financial services.  Tokyo and Paris came second and third.

But when we look at what concerned women most, the poll offers proper food for thought. In London, for example, experts cited the gender pay gap (a recent study by the Chartered Management Institute and XpertHR found on average, women earned £12,000 less than their male counterparts, while just 26% of director-led roles are filled by women as opposed to 74% by men) as well as extortionate childcare costs, as two of the major issues facing women today.
 

Building on success: PPPs in a new era of Canadian infrastructure

Mark Romoff's picture

Also available in françaisلعربية 


Photo: Hubert Figuière | Flickr Creative Commons

Canada has quietly become a leading player in the global PPP space. The unique Canadian version of the procurement model has evolved from an innovative idea promoted through the wisdom and passion of a few early believers and visionaries into a widely applied approach, embraced by all three levels of government and in every region of the country.
 
What might seem an “overnight success” has, in fact, taken 25 years of listening and learning to develop a smart, innovative, modern approach to infrastructure and service delivery using Public-Private Partnerships. It’s an approach that ensures real value for tax dollars and the efficient use of precious public resources.

Pipeline to Work: Including persons with disabilities in skills development and employment projects

Charlotte McClain-Nhlapo's picture
Photo: Dane Macri/The Advocacy Project via Flickr CC
Photo: Dane Macri/The Advocacy Project via Flickr CC.

The relationship between poverty and disability goes both ways: disability increases the risk of poverty, and the conditions of poverty increase the risk of disability.

Yet, little attention has been given to the employment readiness of persons with disabilities. This is of concern given that the employment rates of persons with disabilities are a third to half of the rates for persons without disabilities, with unemployment rates as high as 80%-90% in some countries.

[Learn more: Disability Inclusion]

Disability is a complex, evolving, and multidimensional concept. Currently, it is estimated that 15% of the world population experiences some form of disability, with prevalence rates higher in developing countries. As opportunities for sustainable income generation are directly tied to a person’s access to finance, markets, and networks, persons with disabilities usually face significant challenges in accessing these, due to:

  • non-inclusive regulations and policy,
  • lack of resource allocation,
  • stigma and societal prejudice,
  • low educational participation, and
  • inability to access their own communities and city spaces.
To continue building inclusive cities, research tells us that countries cannot achieve optimal growth by leaving behind a large group of their citizens – persons with disabilities – with economic losses from employment exclusion ranging from 3 to 7 % of the GDP. We also know that when you combine gender and disability, the challenges facing women with disabilities compound. Women with disabilities are more likely to earn less than men with disabilities and they are affected by inaccessible sanitation, smaller social and professional networks, and gender-based violence – see, for example, labor force data from the UK.

We need to do much more to ensure that women with disabilities are mainstreamed into projects that seek to empower women as entrepreneurs and change agents.

Expanding equitable opportunities for persons with disabilities is at the core of the World Bank’s work to build sustainable and inclusive communities. So, what might a disability-responsive moonshot look like for development projects addressing work for persons with disabilities? Here’s what we’re doing at the World Bank:

These winning photos capture the future of sustainable cities

Xueman Wang's picture
The premise behind the Sustainable Cities photo competition was simple. We wanted to learn what people around the world “see” when they hear the words “sustainable cities.”
 
The submissions – and we at the Global Platform for Sustainable Cities received more than 90 entries from over 40 countries around the world – are very revealing.

What the photographers tried to communicate was a need: both the urgent need for infrastructure that leads to more resilient, sustainable cities, or a need to aspire to greener ideals of building sustainable communities for all.

There is no better day than today, World Cities Day, for us to share with you the 10 finalists – including 3 winners and an honorable mention for climate action – of the photo competition.

In the winning photo by Yanick Folly, one can practically feel the chaos of a city in Benin, the smell of exhaust fumes as cars crawl up alongside motorcycles and pedestrians down narrow alleyways.

Yanick Folly (Benin) – Winner
Growing day by day, our world is always moving. Just see the big vibrant Benin market. #SustainableCities

The photo is also a reminder that cities are made of people. Any set of solutions for “sustainable cities” will have to make sense to a city’s inhabitants, who tread its streets daily.
 
In other photos, the aspiration is palpable. 

Many of the photographers are nationals of developing countries from all over the world. Yet quite a few of them shared photos of cities we regard as environmentally friendly: Singapore, Amsterdam, London, and Paris... We saw many photos of parks in developed countries, and heard the same message: These green spaces and pedestrian walkways are what we want in a city.
 
Adedapo Adesemowo (UK / Nigeria)

From a waste dumping ground for oil, tar, arsenic, and lead to an Olympic park. #SustainableCities
Many photos also reflect the vast difference between the aspirational city, and what most people actually live with.
 
We received photos of what many of us may categorize as rural areas, but we should reconsider these preconceptions: some “cities” in developing countries are little more than makeshift towns.
 
So, it is all the more reason why we are excited about this winning photo by Oyewolo Eyitayo from Nigeria. You might think this is an uneventful photograph of a typical urban suburb. Except that the half dirt roads are lined with solar panels.
 
Oyelowo Eyitayo (Nigeria) – Winner
Going solar is a simple & impactful #climateaction that can help combat climate change. #SustainableCities

Why sustainable mobility matters

Hartwig Schafer's picture
Photo: Mariana Gil/WRI
In the 1960s, the vision of future mobility was people with jet packs and flying cars – we believed these innovations wouldn’t be far off after the moon landing in 1969. Obviously, the reality in 2017 is somewhat different.

Today, we have congestion in cities, rural areas cut off from the rest of the world, and too many people without access to safe, efficient, and green transport. This stifles markets and hinders people from the jobs that will help them escape poverty. Without access to sustainable mobility, it will be much harder—if not impossible— to end poverty and achieve the Sustainable Development Goals (SDGs).

And perhaps the most tragic reality is this: that approximately 1.3 million people die each year in traffic-related incidents. Young people, those between the ages of 15-29, are the most affected by road crashes. This heartbreaking and preventable loss of life should be a clear signal that road safety matters.

At the same time, how we change transport is vitally important and will impact generations to come.

Sustainable mobility: Who's who and who does what?

Shokraneh Minovi's picture


Some might call it an existential question. Some may be surprised that the answer is not clear. When it comes to sustainable mobility initiatives and stakeholders, who is who, and who does what? Addressing these questions is a key pre-requisite to the transformation of the transport sector and the realization of the Sustainable Development Goals.

The SDGs, the Global Decade of Action for Road Safety, the Nationally Determined Contributions (NDCs), the Vienna Programme of Action for Landlocked Developing Countries, over 100 different organizations and initiatives… It’s enough to make your head spin! As the world increasingly recognizes the importance of mobility to the overall sustainable development agenda, the number of stakeholders in this arena has been growing steadily. Although many established groups have been warning us for years about the role of transport in the fight against climate change—the sector accounts for some 23% of all energy-related greenhouse gas emissions—many newer players are now adding their voice to the global conversation.

From public transport agencies to car companies and ride-sharing platforms, clean fuel advocates, maritime transport groups, and electric vehicle proponents, a dizzying array of sector-specific initiatives have emerged over the last few years. Newer city-specific coalitions, such as the C40 Cities Climate Leadership Group and the Compact of Mayors, have played a critical role in relaying these concerns at the local level. However, global initiatives have been the ones that have seen the most impressive growth. Also in the mix are globally minded, from UN entities to smaller NGOS, as well as region-specific organizations such as regional development banks.

What’s the solution to untangling this web of stakeholders? Over the past six months, the World Bank, with support from the World Economic Forum, has mapped out major transport initiatives and organizations as comprehensively and systematically as possible.

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