City growth dashboards – terrax.africa

terrax.africa

City growth dashboards

City growth dashboards

The city growth dashboards quantify and offer insights into the development and growth of a city over time. Mostly, satellite images of two years of a city with a gap of 5 -10 years are processed and the data is made available. This allows to discover changes on coordinate or building level and to calculate which parts of a city have been growing how much. Find more information about accuracy on Precision and recall.

City growth overview

The first section calculates the growth of buildings between the two base years. For instance, in the Abuja area the growth of buildings is around 96% between 2010 and 2019. On average, this equals to about 19340 new building that are constructed. The density compares the average number of buildings per hectare between the two base years. In Abuja, average number of houses per hectare was around 16.28 in 2010 and increased to 18.69 in 2019. This is an increase of around 15%.

Quarter and building type growth overview

Buildings per quarter shows the number of buildings in the two different years. In the Abuja area, it is evident that buildings that cannot be matched to quarters have been growing the most. The second highest growth could be observed in Garki quarter.

The building type growth chart illustrates the number of growth focusing on the different building types. The definition and methodology behind the building types can be found on the Building types and colors site.

Roof color changes and type and color growth combined

The roof color graph highlights the development of different roof colors in absolute numbers. For instance, in Abuja, mostly houses with gray roofs were built followed by red or brown roofs.

The number of buildings per type and color graph shows the growth in percentages of building type and roof color combined. Note that roof colors can  change over time (weather, rust, etc.).  For instance, our data suggests that Abuja had a 15 times increase of bungalows with a gray roofs between 2010 and 2019.

Density change overview

Density change shows how many more or less buildings can be found per hectare. Overall, density of bungalows in Abuja increased by over 250% compared to 2010 and houses with blue roofs declined by more than 80%. This could mean that blue roofed houses have either turned into another color or have been replaced.

Relative building growth per quarter

Building growth per quarter shows the percentage change of new buildings. For instance, the lowest growing quarter in Abuja was the Central Business district between 2010 and 2019 with a growth of new buildings of around 28%.

Bungalow growth in percentage and absolute growth of bungalows per quarter

These two charts provide insights in bungalow growth percentage and their absolute numbers. For instance, they show that in Wuse district, the absolute growth was the highest in terms of bungalows but the relative growth was the lowest with 73% of all quarters.

Bungalow and building density bubble chart comparison

The two bubble charts let you compare the state of quarters and their development in terms of bungalow density and general density growth. For example, in 2010, Dutse in Abuja was the quarter with the lowest density whereas in 2019 it was the Central Business District.