http://www.engineeringnews.co.za
  SEARCH
Login
R/€ = 13.05Change: 0.09
R/$ = 12.00Change: 0.15
Au 1199.94 $/ozChange: 23.74
Pt 1143.00 $/ozChange: 20.50
 
 
Note: Search is limited to the most recent 250 articles. Set date range to access earlier articles.
Where? With... When?








Start
 
End
 
 
And must exclude these words...
Close Main Search
Close Main Login
My Profile News Alerts Newsletters Logout Close Main Profile
 
Agriculture   Automotive   Chemicals   Competition Policy   Construction   Defence   Economy   Electricity   Energy   Environment   ICT   Metals   Mining   Science and Technology   Services   Trade   Transport & Logistics   Water  
What's On Press Office Tenders Suppliers Directory Research Jobs Announcements Letters Contact Us
 
 
 
RSS Feed
Article   Comments   Other News   Research   Magazine  
 
 
Mar 09, 2012

South Africa 2011 satellite imagery mosaic now available

Back
Agriculture|Africa|Housing|Water|Africa|Environmental|Water
Agriculture|Africa|Housing|Water|Africa|Environmental|Water
agriculture|africa-company|housing|water-company|africa|environmental|water
© Reuse this



The Earth Observation division of the South African National Space Agency (Sansa) recently launched the latest edition of its mosaic of satellite imagery of the whole of South Africa, using data from the Spot 5 earth observation satellite. Assembled from imagery taken and collected from January 24 to December 20 last year, it is known as the Spot 5 Mosaic 2011.

“The mosaic can be used for many purposes,” highlights Sansa Earth Observation production manager Natalie Diemer, “[like] housing and urban planning, agriculture (especially determining crop yields), water and, particu-larly, dam monitoring, environmental monitor-ing, forestry monitoring, and so on.”

More than 1 000 images were acquired over eleven months, most during winter when cloud cover is minimal over most of the country. “Cloud cover is always a problem,” she observes. Of these, 952 were used in the creation of the mosaic. These were composed of 476 multispectral (colour) images with a resolution of 10 m and 476 panchromatic (black and white) images with a resolution of 2.5 m. These were combined to create 476 2.5 m resolution colour scenes, which were “mosaicked” to create the image of the entire country. This was then divided into squares, called tiles, to produce the final product.

The merging of the two types of image to form the scene is done automatically. “But, sometimes, there is a glitch in the process,” says Diemer. “So every scene needs to be checked manually. My team does this.” The processing of the imagery started while the collection process was still under way. “The making of the mosaic is quite a big task,” she avers.

The processing of the imagery to what is called Level 3 B – the level required for the mosaic – took eight months, and involved orthorectification (positioning and elimination of distortion in the images), pansharpening (transforming lower resolution colour images into higher resolution colour images), true colour conversion, colour balancing, manual editing to reduce cloud cover and eliminate “no data areas”. The entire mosaic is supplied on a single disc, and is available in different formats – UTM, tiff (zipped); geographic, tiff (zipped); geographic JP2000 format, compressed; geographic, ecw format (zipped) and degraded to 10 m resolution, geographic, tiff (zipped).

“We send out about 30 discs,” she reports. Each province gets one, with the data for its territory; others go to the Presidency, govern-ment departments and government agencies such as South African National Parks.

In addition, Sansa Earth Observation sup-plies discs containing each scene separately and providing both the final scene and the two images that make it up. Each set comprises two discs. These are used for scientific research and are supplied, for example, to universities. About 15 such sets of discs are issued. Most images on these discs have been processed to Level 3 A quality, a process which took six months and included orthorectification, pansharpening and “lots of checking”.

The first Spot 5 mosaic of the country was compiled in 2006. “In 2006, the mosaic of the country had a lot of wide-angled images,” states Diemer. “[The year] 2011 was the first time that pretty much all the images were taken at a very narrow angle.” The narrower the angle, the better the positional detail revealed.

However, while, with the wide-angle images, the entire country was covered, with the narrow angle images, there are six small parts of the country that have not been covered. All of these are very small, indeed, amounting to gaps of less than 200 m2 in the coverage – the equivalent of a cloud. However, this will not be a problem as Sansa will be able to supply newer imagery of the areas concerned, should it be required.

Spot 5 was launched in 2002 and is operated by European space company Astrium. Spot is a French acronym: Satellite Pour l’Observation de la Terre (Earth observation satellite, in English). In terms of its licence from Astrium, Sansa can only supply the mosaic to government departments, agencies and universities.

Edited by: Martin Zhuwakinyu
© Reuse this Comment Guidelines (150 word limit)
 
 
 
 
 
 
 
 
Other Environment News
The Coega Development Corporation (CDC) is currently rolling out a R126-million sanitation upgrade project at rural schools in the Eastern Cape on behalf the Eastern Cape Department of Education (DoE). The programme will see 947 toilets built at 108 schools in the...
Many of South Africa’s sewage treatment plants face major challenges, including the lack of technical capacity and funding to maintain and operate ageing sewage treatment infrastructure, as well as the ability to expand the sewage treatment capacity to meet the...
South Africa’s municipalities need to develop an integrated master plan to address delivery constraints of the country’s wastewater treatment plants, says consulting engineering firm WSP Parsons Brinckerhoff Africa technical director Leon Saunders. He points out that...
Article contains comments
More
 
 
Latest News
Top aluminium producer United Company Rusal will start producing metal at its Boguchansk project, in Russia, by June and will ramp up output over the following year depending on demand, the company's chief executive said on Monday. Weak aluminium prices are forcing...
Dubal Holding, the holding company for Dubai's stake in Emirates Global Aluminium and other assets, is considering possible acquisitions in local and international energy projects, it said on Monday. The firm was looking for equity interests related to coal, solar,...
South African mining and energy adviser Ted Blom has raised a litany of concerns about the state of power utility Eskom and has warned of runaway costs and shortfalls in coal and water, as well as rail capacity. Blom was surprised by the recent buoyancy shown by...
More
 
 
Recent Research Reports
Steel 2015: A review of South Africa's steel sector (PDF Report)
Creamer Media’s Steel 2015 report provides an overview of the key developments in the global steel industry and particularly of South Africa’s steel sector over the past year, including details of production and consumption, as well as the country's primary carbon...
Projects in Progress 2015 - First Edition (PDF Report)
In fact, this edition of Creamer Media’s Projects in Progress 2015 supplement tracks developments taking place under the Renewable Energy Independent Power Producer Procurement Programme, which has had four bidding rounds. It appears to remain a shining light on the...
Electricity 2015: A review of South Africa's electricity sector (PDF Report)
Creamer Media’s Electricity 2015 report provides an overview of State-owned power utility Eskom and independent power producers, as well as electricity planning, transmission, distribution and the theft thereof, besides other issues.
Construction 2015: A review of South Africa’s construction sector (PDF Report)
Creamer Media’s Construction 2015 Report examines South Africa’s construction industry over the past 12 months. The report provides insight into the business environment; the key participants in the sector; local construction demand; geographic diversification;...
Liquid Fuels 2014 - A review of South Africa's Liquid Fuels sector (PDF Report)
Creamer Media’s Liquid Fuels 2014 Report examines these issues, focusing on the business environment, oil and gas exploration, the country’s feedstock supplies, the development of South Africa’s biofuels industry, fuel pricing, competition in the sector, the...
Water 2014: A review of South Africa's water sector (PDF Report)
Creamer Media’s Water 2014 report considers the aforementioned issues, not only in the South African context, but also in the African and global context, and examines the issues of water and sanitation, water quality and the demand for water, among others.
 
 
 
 
 
This Week's Magazine
Sappi Southern Africa CEO Alex Thiel
Forest products group Sappi has confirmed the selection of its 25 MW biomass-to-power project, to be erected at its Ngodwana mill, in Mpumalanga, as a preferred bidder under the South African government’s Renewable Energy Independent Power Producer Procurement...
Information and communications technology (ICT) distributor DCC is making Windows- and Android-operating systems tablets available through retailers and education equipment suppliers to provide school children with affordable, high-performance education tools. The...
Another cement manufacturer is set to enter the Ugandan market, raising hopes that prices will come down and spur growth in the construction industry. National Cement, a Kenyan manufacturer, has unveiled plans to invest $195-million in a new manufacturing plant in...
With growth rates exceeding that in the developed world – at an average of between 4% and 5% between 2002 and 2014 – African countries provide investors with ample reason to tap into booming consumer demand says Manufacturing Circle executive director Coenraad...
The South African Chamber of Commerce and Industry’s (Sacci’s) Business Confidence Index (BCI) decreased by 3.7 index points month-on-month to 89.1 in March.
 
 
 
 
 
 
 
 
 
Alert Close
Embed Code Close
content
Research Reports Close
Research Reports are a product of the
Research Channel Africa. Reports can be bought individually or you can gain full access to all reports as part of a Research Channel Africa subscription.
Find Out More Buy Report
 
 
Close
Engineering News
Completely Re-Engineered
Experience it now. Click here
*website to launch in a few weeks
Subscribe Now for $96 Close
Subscribe Now for $96