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What is Remote Sensing and how can it add value to your project?

Remote sensing is the acquisition of information about an object or phenomenon without making physical contact with the object. Through maximization of the spectral, spatial and temporal resolution of a satellite sensor, remote sensing techniques can map most environmental phenomenon on the earth with less expert knowledge, time and cost, and provide the appropriate quantitative information necessary for combating environmental issues. SEF takes advantage of the benefits of remote sensing through using satellite imagery to map vegetation types, vegetation health, alien invasive species, land cover types, gully erosion and so much more.

The terms spatial, spectral and temporal resolution can be quite confusing when choosing which remote sensing imagery you would like to use for a specific project. You know what kind of map you want to develop but you may not know what goes behind the details of the imagery selection. Firstly, spatial resolution relates to the size of the smallest possible feature that can be detected in the satellite image (Wilkie and Finn, 1996). The spatial coverage offered by certain satellite imagery is much larger than a conventional photograph, for example, “it can take 5000 conventional vertical aerial photographs obtained at a scale of 1:15 000 to fit the geographic extent of a single Landsat image” (Jensen, 2005). Such a large spatial coverage allows for a direct perspective of the regional mix of features on the ground. Secondly, the spectral resolution talks to the dimension and number of wavelength regions of a sensor system. The spectral resolution allows for feature extraction methods, for example ideal band combinations, vegetation indices and classification algorithms. Such techniques combined with the repetitive coverage of a particular area by satellite systems (temporal resolution) can lessen the time and cost required to produce a map. All of the above offers the possibility of monitoring the extent and evolution of various environmental issues.

SEF is equipped with state of the art remote sensing equipment and has a team of Geomatics experts that can effectively map environmental information from satellite imagery. The SEF Geomatics team has successfully mapped various land cover types for three river basins in Mozambique: Ruvuma, Save and Buzi river basins. These river basins cut across Zimbabwe, Mozambique and Tanzania, which made having a land cover database that was consistent and up-to-date quite a challenge. SEF took advantage of the spectral resolution from Landsat 5, seven bands, to produce an up-to-date, seamless land cover map for these river basins. The techniques used proved to be very cost effective as it allowed the specialists to have a more strategic approach to their field investigations.

The above study was just one mapping exercise which SEF has been involved in. The Geomatics team and specialist team at SEF have also recently partnered up to offer its services to forestry mapping in Ghana, alien invasive species mapping, gully erosion mapping and various Strategic Environmental Assessments in South Africa. SEF looks forward to increasing its remote sensing footprint across Africa and offering its clients more cost effective solutions.

References:

Jensen, J. R. (2005). Introductory digital image processing (3rd ed.). United States of America: Pearson Prentice Hall.

Wilkie, D. S., and Finn, T. J. (1996). Remote sensing imagery for natural resources monitoring. New York: Columbia University Press.

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