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Posts tagged Orthorectification

Volcanoes of La Réunion – December 31st, 2009

20.9S 55.4E

December 31st, 2009 Category: Image of the day, Volcanoes

La Réunion - December 11th, 2009

La Réunion - December 11th, 2009

This orthorectified image portrays the island of La Reunion, which is 63 kilometres (39 mi) long, 45 kilometres (28 mi) wide, and covers 2,512 square kilometres (970 sq mi). It is similar to the island of Hawaii insofar as both are located above hotspots in the Earth’s crust.

On the eastern end of the island, the Piton de la Fournaise shield volcano rises to more than 2,631 metres (8,630 ft) above sea level. It is sometimes considered a sister to Hawaiian volcanoes because of the similarity of climate and volcanic nature. The volcano is very active, having erupted more than 100 times since 1640, and is thus monitored constantly.

Another volcano, the Piton des Neiges is located northwest of the Piton de la Fournaise. It is the highest point on the island at 3,070 metres (10,100 ft) above sea level. Collapsed calderas and canyons can also be observed southwest of the mountain. Unlike its active neighbor, the Piton des Neiges is extinct.

Sari and the Alborz Mountains, Northern Iran

36.5N 53.0E

December 31st, 2009 Category: Snapshots

Iran - December 14th, 2009

Iran - December 14th, 2009

This orthorectified image stretches from the southern coast of the Caspian Sea to the northern slopes of the Alborz Mountains in Iran. The large white patch is the city of Sari, the provincial capital of Mazandaran. Its population is estimated to be 261,293, as of 2006, and it has a land area of 5,089 square kilometers.

The Alborz Mountains in northern Iran stretch from the borders of Armenia in the northwest to the southern end of the Caspian Sea, and end in the east at the borders of Turkmenistan and Afghanistan. The tallest mountain in the Middle East, Mount Damavand, is located in the range.

The Alborz mountain range forms a barrier between the south Caspian and the Qazvin-Tehran plateau. It is only 60-130 km wide and consists of sedimentary series dating from Upper Devonian to Oligocene, prevalently Jurassic limestone over a granite core.

Geography of Italy’s Veneto Region – December 30th, 2009

45.4N 12.3E

December 30th, 2009 Category: Image of the day, Snapshots

Italy - November 30th, 2009

Italy - November 30th, 2009

Veneto is the eighth largest region in Italy, with a total area of 18,398.9 km2 (7,103.9 sq mi). It is located in the north-eastern part of Italy and is bordered by four other Italian regions and Austria. The north-south extension of Veneto is 210 km (130 mi) from the Austrian border to the mouth of the Po and its east-west extension is 195 km (121 mi) from the eastern shore of Lake Garda on the west to the mouth of the River Tagliamento on the east.

Veneto can be divided into four areas, parts of which are all visible in this orthorectified image: the northern Alpine zone, the hill zone, the lower plain and the coastal territory. Twenty-nine% of its surface is mountainous (Carnic Alps, eastern Dolomites and Venetian Prealps). The best known massif in the Dolomites is the Marmolada, while the highest, at 3,342 m (10,960 ft), is the Tofane-massif. The Venetian Prealps are not as high and range between 700 m (2,300 ft) and 2,200 m (7,200 ft).

Fifty-seven% of the Veneto region is covered by the Po Valley, a plain extending from the mountains to the Adriatic Sea, broken only by some low hills: Colli Berici, Colli Euganei, Colli Asolani and Montello, which constitute the remaining 14% of the territory. The Venetian plain itself is subdivided into the higher plain (gravel-strewn and not very fertile) and the lower plain (rich in water sources and arable terrain). The lower plain is both a mainstay of agricultural production and the most populated part of the region.

Several rivers traverse the region: the Po, Adige, Brenta, Bacchiglione, Livenza, Piave, and Tagliamento. The eastern shore of the largest lake in Italy, Lake Garda, belongs to Veneto. The coastline covers approximately 200 km (120 mi), of which 100 km (62 mi) are beaches. The coasts of the Adriatic Sea are characterized by the Venetian Lagoon,  visible near the shores on the right, a flat terrain with ponds, marshes and islands. The Po Delta to the south features sandbars and dunes along the coastline. The inland portion contains cultivable land recently reclaimed by a system of canals and dikes.  The delta is a stopping-point for migratory birds.

Colville River Crossing Alaska’s North Slope Borough, USA

70.2N 150.9W

December 29th, 2009 Category: Lakes, Rivers

USA - December 19th, 2009

USA - December 19th, 2009

The landscape of Alaska’s North Slope Borough is dotted by many lakes in this orthorectified image. The borough has a total area of 94,763 square miles (245,436 km²), of which, 88,817 square miles (230,035 km²) of it is land and 5,946 square miles (15,399 km²) of it (6.27%) is water.

Its western coastline is along the Chukchi Sea, while its eastern shores, beyond Point Barrow, are on the Beaufort Sea (visible in the top part of this image). Here, the Colville River can be seen crossing the North Slope and spilling into the Beaufort Sea.

The Colville is a major river of the Arctic Ocean coast of Alaska in the United States, approximately 350 mi (560 km) long. One of the northernmost major rivers in the North America, it drains a remote area of tundra on the north side of the Brooks Range entirely above the Arctic Circle. The river is frozen for more than half the year and floods each spring.

Upon opening the full image, the river can be seen flowing through the foothills on the north side of the Brooks Range, broadening as it receives the inflow of many tributaries that descend from the middle Brooks Range. After flowing across the Arctic plain, it enters the western Beaufort Sea in a broad delta near Nuiqsut, approximately 120 mi (190 km) west of Prudhoe Bay.

Cape Kumukahi and Hilo, in Hawaii, USA

19.7N 155W

December 28th, 2009 Category: Snapshots

USA - December 18th, 2009

USA - December 18th, 2009

This orthorectified image of eastern Hawaii includes Cape Kumukahi, the easternmost point of the island chain. The cape lies at the end of the east rift zone of the slopes of Kilauea and has been threatened several times by eruptions.

Moving westward along the coast from the cape, the city of Hilo can be seen along the shores of Hilo Bay. It is the largest settlement on the island of Hawaii, and the second largest settlement in the state. The population was 40,759 at the 2000 census.