Subscribe

Satellite map offers govt solutions

Marin'e Jacobs
By Marin'e Jacobs
Johannesburg, 20 Jun 2013
The latest version of the Spot 5 national mosaic has seen a number of improvements since it was first incepted in 2006.
The latest version of the Spot 5 national mosaic has seen a number of improvements since it was first incepted in 2006.

The South African National Space Agency (SANSA) yesterday unveiled the latest Spot 5 national mosaic, a combination of images taken by the Spot 5 satellite to create a map of the entire country. This map is used mostly by government departments to address various issues facing SA.

SANSA Earth Observation MD Dr Jane Olwoch explains the mosaic is made up of 485 images taken by the Spot 5 satellite, which are downloaded and processed by SANSA over 12 months and compiled to create a map. "The detail within each of the tiles of the mosaic provides information of an area 60km by 60km," says Olwach.

The national mosaic was first incepted in 2006, and an updated map is created annually. According to a statement released by SANSA, this year's national mosaic has seen a number of improvements, including an enhanced method for colour balancing, an improved true colour algorithm, and no gaps in coverage. Another improvement is the inclusion of Web map applications in the packaging, which allow users connected to the Internet to explore the image footprints and preview the Spot 5 products for each of these footprints.

SANSA has also secured agreements with supplier of Spot imagery, Astrium, to acquire Spot 6 and 7 data, which will offer higher-resolution images.

Mapping the benefits

Acquiring the data for one map costs R17 million, excluding staff salaries and the storing and processing of data. "It is definitely a costly exercise, but the value you get out of it is much more than the money you put in," says Olwach.

Olwach explains that the data provided by the national mosaic is used for a variety of purposes, such as comparing the annual maps to measure the growth of informal settlements, industrial development and the country's urban footprint.

"The Department of Agriculture, Forestry and Fisheries uses the map to look at pollution in the water, particularly in Hartebeespoort Dam," says Olwach. The department also uses the map to measure climate change, as well as the viability of land for agriculture.

"They also use it to estimate crop produce. For example, they have seen this year there is going to be a reduction in maize, which means an increase in the price," says Olwach. The map has even been used by police to monitor the country's borders.

Although the map is primarily used by government, it is made available to all public entities, including schools, universities and research institutions. Users are able to access the SANSA Earth observation catalogue, which contains Spot 5 and other satellite imagery from the data archive.

"It is a significant achievement for SANSA to be able to provide a state-of-the-art product that brings huge impact to the lives of our citizens when used by our government stakeholders," says Olwach.

Share