Africa and the Middle East - Remote Sensing Application - Completely Remote Sensing, GPS, and GPS Tutorial
Africa and the Middle East

Africa is a continent noted for its stark varieties of diverse landscapes. While there are relatively few large cities, and many nations are still in the third world underdeveloped category, populations of pluralistic ethnic groups are distinctive. We will establish a framework for viewing Africa using the next four illustrations. The first sets the geographic boundaries of its many nations, and shows its relief:

Geographic Map of Africa, with shaded relief.

This relief can be emphasized to better show the distribution of mountains and highlands:

Shaded relief map of Africa.

Prominent are the Atlas/Anti-Atlas group of mountains in Morocco, the Ahaggar, the Tibesti, the Ethiopian Highlands, the East African Rift zone, and the high plateaus of southern Africa. These are labeled and located in this map:

The next pair show a construction of the main surface cover types (desert, forest, savannah, etc.) and a classification of the principal types.

Land Cover map of Africa; green is vegetation, yellows and browns are desert and some savannah.
Map classifying the natural land cover types.

The yellow in the land cover map is listed as desert. Indeed, the northern part of Africa is mostly desert except for vegetated coastal areas. Much of the desert is rock rather than sand. This Landsat mosaic of northern Africa shows the actual variety of land cover types (rocks are darker; sand is yellowish):

Landsat mosaic of northern Africa, made by Earthsat, Inc.

We will begin our journey through Africa in this northern sector. Shown first is the western gateway to Africa, across the Mediterranean from Gibraltar to Tangiers, Morocco:

Southern Spain, Gibraltar (in the curved Bay in the upper right), and Tangiers, Morocco; Landsat image.

Gibraltar is a British colony, won from Spain after a war. The best known landmark is the Rock of Gibraltar (the symbol of Prudential Insurance). Here is a ground photo:

View of the Rock of Gibraltar.

This limestone massif is actually a sea stack now emerged as sealevel has readjusted. This view shows the Rock as part of a spit:

The Rock of Gibraltar in context with its location on a sandy spit.

Further south along the Moroccan coast is the city of Casablanca, which gained fame in the West as the locale of the movie "Casablanca", starring Ingrid Bergman and Humphrey Bogart:

Casablanca; SPOT image.

To the east are the Atlas and Anti-Atlas mountains of southern Morocco. These are known locally as the Jebel Bani. The Atlas and Anti-Atlas Mountains of northwestern Africa, seen earlier on page 2-6, are a collision-fold belt similar (and related) to the Appalachians. The region is sparsely populated and experiences low rainfall. The next three images show these mountains in an Envisat, a Landsat, and a Digital Globe perspective view:

The Atlas group of mountains in Morocco.
The Anti-Atlas Mountains of Morocco; Landsat image.
Perspective view of the High Atlas mountains.

It was in the eastern end of the Atlas that the U.S. Army had several fierce battles with the German Army in 1943 during World War II.

Algiers is one of the larger African cities on the Mediterranean coast. This capital of Algeria is seen in a Landsat subscene:

Algiers.

Tunis is the capital of Tunisia. It is located on the Mediterranean Sea coast, not far from the ancient city of Carthage (a city founded by the Phoenicians [whose home land was just north of modern Israel]).

Tunis, in Tunisia.

Many people, influenced by movies, visualize the African desert as never-ending sand dunes. This next scene, in south-central Algeria, is in fact a more typical expression of the Sahara Desert. In the lower left third is the Tademait Plateau, underlain by sedimentary rocks, and crossed by dendritic intermittent streams whose channels were cut during a wetter epoch in the Pleistocene. The land in the lower right is the Tidikelt, a barren gravel-surfaced plains. The upper part of the image is a segment of the Grand Erg Orientale, whose most prominent feature is the series of longitudinal dunes first established when the wind blew more from west to east than today. This whole region is almost uninhabited.

A typical landscape expression of both rocky and sand-dune covered areas in the western Sahara Desert, here in southern Algeria.

The Ahaggar Mountains (also known as the Hoggar Mountains) of southern Algeria are shown in this image, together with a ground scene:

Because of the light colored background afforded by the sand, rocks such as basalt stand out in sharp contrast. Astronauts generally comment about one feature they see almost as the "African landmark" - the fresh basaltic flow from the Pic Tousside volcano in the Tibesti Mountains of northern Chad. Here is a Landsat-7 ETM+ image of this feature within the Tibesti Mountains, first in a fuller setting and then in close-up:

The Tibesti
The Pic Tousside volcano.

As said above, the hallmark of the Sahara is the absence of notable vegetation, so that the desert from a distance looks like a great expanse of sand and soil having a characteristic yellow to orangish color overall, without much diversity of features when an image is low resolution. This Envisat image shows these characteristics; the scene extends from the Anti-Atlas Mountains on the north to the Inland Delta of the Niger to the south (individual Landsat images show these areas on this page).

Much of northwest Africa seen by Envisat.

When northern Africa is mentioned, many people get images of deserts. The Sahara is the greatest expanse of sand and dunes in the world. This next scene is typical:

The Sahara Desert

Desert people make up much of Mali's population. Mali is one of the countries of Sub-Saharan Africa (desert interspersed with vegetation owing to greater rainfall). The nation is crossed by the Niger River on its way to the bottom of the western hump of Africa. During the rainy season water spreads over the flat lands producing an "inland sea" of sorts. This feature is actually referred to as the Inland Delta of Mali. The water in this scene is black, with thick wetlands vegetation in red. The Bambara and Peuhl peoples farm the area and raise Zebu cattle.

The Inland Delta of the Niger River in Mali.

Near Mali is the small country of Burkim Faso (chances are you've never heard of it but check it on the map of Africa above). Its capital - Ouagadougou - is a challenge to pronounce but is a thriving city of more than a million:

SPOT image of Ouagadougou.

Africa conjures up an image to many as a vast dense jungle. However, most of the continent is ecologically either a savannah (brush and grasslands) or a desert similar to the type in the image just above. But, in the "Congo", much of that region being in today�s Democratic Republic of the Congo (DRC; known for a while as Zaire), a true jungle (Tarzan type) - much like that in the Amazon - of continuous rain forest made up of teak, ebony, copal, palm, and cedar trees remains one of the pristine timber regions of the world, although deforestation is now underway. Here in this Landsat MSS false color scene, this status is disclosed by the solid expanse of red (= NearIR) vegetation; usually the region is largely cloud-covered but this clear March 1973 scene is unusual. The large river crossing the scene is the Congo (renamed the Zaire) River; the large tributary is the Aruwimi. The Congo River is 4370 km (2718 miles) in length, making it one of the longest on Earth; it is navigable far upstream.

This Landsat MSS false color image sharply defines the unbroken, dense jungle vegetation in the Democratic Republic of the Congo; the Congo River flows through the scene.

As seen from space in natural color, the Congo jungle looks like this:

Satellite image of the Congo.

The jungle is spread over both mountains and flatlands, as shown in this ground photos:

Typical rainforest in the Congo.
Mountainous jungle in the Cameroon.
Another ground scene of the African tropical rainforest.

Two of the largest cities in the DRC are Brazzaville and Kinshasa (the latter is approaching 8 million); both are seen in this photo taken from the International Space Station; an aerial view of Kinshasa is below it.

ISS photo of Kinshasa and Brazzaville.
Aerial view of Kinshasa.

However, the tropical forests are shrinking and desertification from the Sahara is moving south. Some of this loss is natural but much has resulted from land clearing by the indigenous tribes. Here is a Landsat view of part of Ghana and Togo, in which once dominant rain forest has been removed by cutting and burning, converting the land to savannah. The dark areas are probably burn scars from recent burns.

Segments of Ghana/Togo showing now deforested land given over to herd raising and some farming; Landsat-1 image.

But, the still extensive forestlands offer shelter to many of the indigenous (but to zoo-goers, exotic) animals, such as the African gorilla. Radar imagery helps to penetrate the tropical growth, as shown in this SIR-C image of Lake Kiva and parts of Rwanda, Uganda, and Zaire. One prominent volcano is Mt. Karisembi:

SIR-C/XSAR image of tropical forests and underlying topography in Central Africa.

The next Landsat scene (second below) covers part of northern Kenya in East Africa. The dominant feature running north-south through the right half of the Landsat image is the African Rift Valley, shown here in dark bluish-gray representing basaltic rocks. Notable are the many scarps caused by normal faulting as the rift develops and pulls apart. (See page 2-9 for another example of this rift terrain.) Small volcanoes dot the Valley. The lake at the bottom is Lake Natron, whose level varies seasonally, and as it dries leaves sodium carbonate deposits. The lake at the top of the Valley is Lake Naivasha. Relief in the region exceeds 1000 meters (several thousand feet), so that higher elevations remain forested whereas lower areas are near-desert. Rain in the region can be up to 100 cm (40 inches) gives that area enough moisture to support crop farming, including coffee planation.

Part of the East African Rift Zone, in Kenya, shown in a Landsat-1 image.

The capital of Kenya, Nairobi, lies at the right margin about one-third down from the top (it is a bluish area midst the red). A SPOT image shows the city; below it is a ground photo that indicates the modern development of Nairobi:

SPOT image of Nairobi.
Aerial view of Nairobi.

Like all continents, parts of Africa are mountainous as well. You saw the highest peak in Africa, Mount Kilimanjaro, a huge volcano, on the Game page of this Section. Because the coloring is so attractive, we show it (framed by IR red vegetation; near center right edge) again in this Landsat image which covers a larger area:

Kenya, with Mt. Kilimanjaro.

Kilimanjaro is the tallest peak in Africa (5895 m; almost 20000 ft). It is quite photogenic, as evident from this ground view:

Mt Kilimanjaro from the ground.

Landsat data have been used to portray this volcano, as a perspective, as though viewed obliquely from above;

Perspective view of Kilimanjaro; note the extensive dark green band - this is a rain forest that covers the lower slopes of the volcano..

Landsat 10 meter ETM+ imagery shows the top of Kilimanjaro from above. Using earlier imagery, the extent to which the summit glaciers (20 individuals) has wasted away since 1962 has been plotted on the Landsat image. Kilimanjaro is an "indicator glacier" used by advocates of global warming to show the effects of temperature rise in the last half century; the famed "Snows of Kilimanjaro" are fast disappearing.

Landsat ETM+ image of Mt. Kilimanjaro's summit area; orange line indicators location of earlier glaciers.

In Tanzania, between Lake Victoria (next page) and the volcanoes west of Kilimanjaro lies the Serengeti National Preserve, one of the most stupendous game lands in the world. The park is largely flat plains, as depicted in this SRTM topographic image; the volcano is Ngorongoro:

SRTM radar deroved topographic map of the Serengeti and neighboring countryside.

This Landsat subimage gives a further impression of the grasslands terrain:

Landsat subscene of the Serengeti plains, with Lake Victoria in the upper left.

This is a typical photo of the Serengeti landscape.

View of Serengeti landscape.

The wildlife is diverse, plentiful, and often spectacular. Lions, elephants, giraffes, hippos, and many other varieties of African animals we have associated with this continent abound. As shown in the next photo, herds of wildebeests, and large white birds (egrets?)attest to the fauna people come to this part of Africa to observe on Safari; the photo below this shows greater diversity.

Wildebeests and egrets.
A variety of wild animals in the Serengeta

Within the Serengeti lies an ephemeral river that has carved out the Olduvai Gorge from Pliocene-Pleistocene sediments. Here is the famous location where the Leakey family and their associate anthropologists have made some of the great discoveries of hominids dating back more than a million years. This ASTER space image shows some details of the immediate area:

The Olduvai Gorge, 'Mecca' for anthropologists.

Small parts of four countries - Zambia, Botswana, Zaire, and Namibia - appear in this Landsat image. The Zambesi River flows through the Kalahari Basin whose vegetation is a savannah grasslands and some swamps.

The Zambesi River in a predominantly savannah region.

Typical savannah land cover (here called the Veld) is dominant in this Landsat image of southwestern Botswana. The mottled pattern is largely the result of the annual controlled brush and grass fires set to prepare the land for later planting. The Kalahari Bushmen inhabit the region.

The Veld of Botswana.

Further to the southwest along the Atlantic is Namibia, a barren land of deserts and treeless mountains. This is the Kaoko Veld region. The eroded fold belt mountains contain rocks of the Damara and Karoo systems:

Mountains of Namibia.

The capital of Namibia (once known as South West Africa) is Windhoek, seen in this SPOT image:

Windhoek, Namibia; SPOT image.

Like so many other African cities, Windhoek would strike the viewer as modern:

Aerial view of Windhoek, Namibia.

South Africa is one of the more advanced countries on the continent. Here is a map of its main geographic features; most of interior South Africa is a plateau surrounded by a long continuous escarpment:

Map of South Africa.

The northwest region of South Africa is a continuation of the Namibian Desert as seen in this image:

The northwest region of South Africa.

In the above scene are a cluster of low mountains in the eastern part of Namaqualand, seen here in this ASTER image; they consist of crystalline rocks, a mix of granitic and metamorphic rocks and basalts, mostly dark in color:

Crystalline rock mountains in Namaqualand.
Panoramic view of Namaqualand mountains.

In this next scene, near the coast in southeastern South Africa, is another fold belt known as the Cape Ranges, a collection of anticlines and synclines running about east-west, and made up of Paleozoic rocks. In places, their elevation exceeds 1500 m (5000 ft). The dark reds associated these mountains imply forests that include evergreens. They block winds coming from the Indian Ocean (lower right) so that precipitation is "wrung out" over them (up 130 cm or 50 inches annually), leaving the interior (left) in a rain shadow that fosters a semi-arid desert flora. Along the top of the scene is the Great (or Drakensberg) Escarpment, a steep cliff nearly 1.5 km (1 mile) high on top of which is a vast peneplain referred to as the Post-Gondwana Surface, dating from the Cretaceous Period. Elevations above the escarpment reach to 2400 m (8000 ft). The region is harsh for living, with low populations.

Part of the Cape Ranges in southeastern South Africa.

The Drakensberg Escarpment in many places is topped by basalt flows which are also jointed, as indicated in this SPOT image:

The top of the Drakensberg Escarpment; SPOT image.

Here is a ground photo of the Escarpment:

Part of the Drakensberg Escarpment.

A continuation of the Cape Ranges carries one to Cape Town and the southernmost tip of Africa - the Cape of Good Hope - as seen in this Landsat view:

SPOT image of CapeTown.

Compare this overhead scene with a close-up ground photo of Cape Town

Cape Town, South Africa.

Nearby are these imposing cliffs composed of basaltic rocks:

Cliffs near CapeTown.

Next we show part of a MISR image that features the largest city in South Africa, Johannesburg, which lies in the heart of the Witwatersand - which contains the main gold-producing fields (numerous underground mines) on the continent:

The Witwatersand, with the city of Johannesburg, portrayed in a MISR image.

Compare this with this photo taken by astronauts aboard the International Space Station:

Astronaut photo (from the ISS) of Johannesburg, South Africa, in which gold mine dumps intersperse with buildings (the suburbs appear greenish because of heavy tree planting).

Johannesburg, the largest in southern Africa, is a distinctly modern city:

Johannnesburg, South Africa.

Just to the northeast of Johannesburg is the South African city of Pretoria, capital of the country, as seen in this Landsat-7 image.

Pretoria, South Africa; Landsat-7.

This Proba CHRIS image provides a more detailed look at Pretoria from space. The city is also involved in gold mining. Beneath it is a panoramic view of the city (the purple tree is the Jacaranda):

Proba image of Pretoria.
The city of Pretoria.

Now, to the Indian Ocean side of Africa.

Source: http://rst.gsfc.nasa.gov/