When you think of Peru, the first city that usually comes to mind is Lima. Why? Well, because Lima is the largest city in the country, with close to 50% of the nation’s urban population living in the metropolitan area; the city also produces 45% of Peru’s GDP. While this level of concentration of population and economic activity may not be a good or bad thing, it points to some imbalances in the urban system in Peru.
Latin America & Caribbean
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).|
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:
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.
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.
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.
The relationship between poverty and disability goes both ways:
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.
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, addressing work for persons with disabilities? Here’s what we’re doing at the World Bank:
- Harkin Summit
- Social Inclusion
- Sustainable Communities
- Global Goals
- Urban Development
- Social Development
- Labor and Social Protection
- Information and Communication Technologies
- Latin America & Caribbean
- South Asia
Economic research is essential for designing and implementing evidence-based solutions to improve job opportunities. In a recent conference organized by the World Bank and IZA, researchers from around the world presented over 30 research papers on important labor topics such as migration, gender, youth employment, and labor policies in low-income countries. Here is an illustrative sample of four innovative works presented during the conference.
Hurricanes Irma and Maria recently devastated the Caribbean region. Infrastructure in Dominica was severely damaged and the country suffered a total loss of its annual agricultural production. The entire population of Barbuda had to be evacuated to Antigua and other islands. Estimates by the World Bank indicate that Irma caused damages equivalent to 14 percent of GDP for Antigua and Barbuda, and up to 200 percent of GDP for Dominica. The increasing frequency of hurricanes poses a threat to the economic development and wellbeing of 40 million people living in the region.
The World Bank and other development institutions acted quickly by offering support to assess damages and losses, respond to the disaster, and assist with recovery by delivering financial packages and supporting emergency operations. However, in the longer term, the focus is on building the resilience of these small island states to natural disasters.
Data: critical for responding to disasters, but also vulnerable to them
Systems of national statistics can provide critical information about the extent of a disaster, help guide recovery operations, and assess the preparedness of countries to future shocks. At the same time, the reliance of National Statistical Offices (NSOs) on local IT infrastructure makes them highly vulnerable to natural disasters. Computers, servers, and networks cannot operate without power; flooding and high humidity destroys hardware and storage media; looting and breaking into abandoned buildings puts sensitive information at the risk of falling into the wrong hands. Fortifying NSO buildings to withstand Category 5 hurricanes and enabling the offices to continue functioning afterwards is prohibitively expensive. Even if such structures were built, staffing would remain an issue, particularly if the entire population of the country was evacuated (as in case of Barbuda).
Cloud computing provides a very effective way to resolve that problem at a small fraction of the cost.
Brazilian youth browse Internet via their smartphones. Photo: TV Brasil.
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
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)
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
- photo contest
- photo competition
- sustainable cities
- Global Platform for Sustainable Cities
- Sustainable Communities
- World Cities Day
- Urban Development
- Social Development
- Climate Change
- Latin America & Caribbean
- The World Region
- Middle East and North Africa
- South Asia
- East Asia and Pacific
- Lao People's Democratic Republic
- United Kingdom