Our Changing Landscape – Flooding in Casablanca - Apollo Mapping
Posted on March 2nd, 2021

Our Changing Landscape – Flooding in Casablanca

In this monthly feature, we span the globe to examine Our Changing Landscape with a time series of medium-resolution PlanetScope satellite imagery. The PlanetScope constellation dates back to 2016 and collects hundreds of millions of square kilometers of four and five-band 3-meter imagery daily! Last month we checked out the untimely demise of one of the world’s most important telescopes, and for the March edition of Our Changing Landscape we turn our focus to Africa and the recent floods in one of Morocco’s best-known cities, Casablanca.

Click on the image above to see an animation of 3-meter natural color PlanetScope imagery collected over Casablanca, Morocco on December 31, 2020 and January 9, January 11 and January 21, 2021. While we always try to provide our readers with the best graphics possible in this piece, sometimes we strike out as we did this month. When you watch this animation, you will not see any major changes over Casablanca and you will not see any evidence of flood waters. What this suggests is that detecting floods in PlanetScope imagery is possible as we have seen it in past pieces, but the flood waters need to be significant and pooled over large areas. Given the narrow roads that characterize Casablanca, even if there was significant standing water, it is likely not visible given the resolution of this data – we will try to do better next month! (Images Courtesy: © Planet 2021)

The PlanetScope Microsat Constellation

PlanetScope is a constellation of more than 150 microsats referred to individually as Doves. Each Dove is able to collect up to 20,000 square kilometers (sq km) per day of 3-meter (m) 4-band multispectral (i.e. blue, green, red and near-infrared [NIR]) imagery; and newly launched SuperDoves collect 5-band multispectral adding in valuable red-edge spectral data. Across the constellation, PlanetScope is archiving more than 200 million sq km of medium-resolution imagery a day, making it the go to source for daily imagery over most locations. This massive archive dates back to 2016, offering the most complete and continuous record of spatial data on the planet since the start of the constellation’s ongoing launch schedule. Collecting 3-meter multispectral imagery is the equivalent of ‘high-resolution’ multispectral data imaged by a 75-centimer (cm) satellite (as this satellite would feature 75-cm panchromatic and 3-m multispectral), making PlanetScope an extremely competitively priced option at just $1.80 per sq km. With well registered images and nearly daily collections of most locations, PlanetScope is the ideal imagery source for this current-events focused series, Our Changing Landscape.

January Flooding in Casablanca, Morocco

Many Americans first heard of Casablanca from the 1942 wartime drama also called, ‘Casablanca’, which painted a romantic image of the African city. Located on the northwestern coast of Morocco, the historic city founded by Berbers is situated between the Atlantic Ocean to the west and then the Bouskoura forest and farmland to the east. The city itself covers about 80 square miles (220 square kilometers) and is home to some 3.7 million residents. With a Mediterranean climate, Casablanca is generally dry receiving an average of 16.2 inches (41.2 centimeters) of rainfall per year, most of it falling in the winter and early spring months.

The start of this year saw an unusually high amount of rainfall hit Casablanca with some 10-inches (25-cm) of precipitation falling from January 6th to 11th – about 70% of their yearly average – with periods of very heavy downpours. And accordingly, in a city not built to handle this amount of rain in such a short time, Casablanca’s infrastructure was inundated with flood waters, causing road to flood over car tires, tunnels to fill and building rooves to collapse. According to local media, at least one person died and four were injured due to the floods – and the pictures strewn across social media showed the extent of the damage and standing water. While it is unclear exactly when the flood waters receded, we are hoping that the 3-meter PlanetScope archive will shed some light on the extent of the damage in the historic city as well as when the waters might have subsided.

If you would like to find out more about using 3-meter PlanetScope imagery for your academic studies, engineering projects or any landscape analysis, let us know at sales@apollomapping.com or (303) 993-3863.

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