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Tammy and the X-band antenna at Hartebeesthoek, which receives SPOT 5 images |
Benefits to the economy and society at large of remote sensing data have long been recognised. Through a winning combination of space technology with sophisticated sensor systems, we can now pick and choose the type of remote sensing data we need for any particular application. Tammy Lotz is a remote sensing specialist at the CSIR Satellite Applications Centre whose research focuses on deriving maximum benefit for South Africa from government-funded remote sensing data.
The southwestern region of the Western Cape is an important agricultural and conservation area. Known as the breadbasket of South Africa, this winter rainfall area produces much of the country’s wheat requirements and rates as a prime agricultural region. Within its boundaries are also found some of the Western Cape’s unique fynbos, which is perfectly adapted to the climate and a prime example of biodiversity. It is a beautiful area, yet frequently perceived to be under environmental threat.
One of the CSIR Satellite Applications Centre’s young and upcoming remote sensing specialists, Tammy Lotz, has excellent credentials to take on a number of research questions related to this region. She loves geography, which can be defined as the study of the earth and its features, inhabitants, and phenomena, and is equipped with remote sensing qualifications to enable her to research both these aspects.
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| Before and after - automatic classification of natural areas, agricultural land and transport features |
She explains, “Fynbos is a priceless natural resource, which is under threat from frequent fires, agriculture and urban expansion. As a first step towards remedying this situation, it is important to determine how this natural asset is being affected by these factors.
“Once this is well-understood, informed decision-making and management are possible to achieve harmony between man and nature.”
Tammy is registered for an MSc in environmental geography at the University of Stellenbosch. “My research focuses on land cover mapping of the areas around Lamberts Bay, Elands Bay, Clanwilliam, Vredendal and the Cederberg – all connected by the Olifants River,” she reveals. Her findings are startling: irrigated agriculture is destroying the fynbos in this area.
She points out, “This change has become more visible over the past five to 10 years. I use satellite images from three satellites, Landsat 1, Landsat 5 and SPOT 5. By swiping or overlaying an older image with a more recent one, it is possible to see clearly the changes brought about by centre pivot irrigation.” Circular patterns of agriculture are created through irrigation, which is primarily used for potato crops.
Tammy’s research will deliver classification of land cover through an automated process. “Once I’ve identified the location of the natural vegetation, this information can be used to create new reserves, with the full cooperation of existing farmers.”
Tammy uses ecognition software for automatic classification of landcover
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For this research project, which aims to classify natural areas, agricultural land and transport features (such as roads and railway lines), Tammy has relied on SPOT 5 imagery. SPOT 5 imagery is funded by a broad funding consortium comprising government departments and government agencies and utilities, and is made available free of charge by the CSIR to South African government departments or local researchers.
Tammy explains more about the process of automatic classification, “Ecognition software is used, on which we set up rules or protocols. A protocol determines the values and sequence by which characteristics of objects or collections of pixels or dots on an image are classified. In this case, the protocol contains spectral, textural and shape values, which refer to visible light, surface cover and topography or surface shape.
“This protocol is run through every SPOT 5 image received since 2006 and objects are classified accordingly.”
A 100% hit rate is unlikely, says Tammy. “Once I’ve looked at the classification and determined its accuracy, I can then go back and adjust the protocol to give better results.”
The end result is well illustrated by giving a different value for each classification, and by adding colour coding for ease of reference.
Her research is a source of great satisfaction to Tammy, “I love my work and enjoy helping out on a range of projects.” Wanderlust is in her blood, however, and she loves to travel.
Tammy in a festive Santa hat on Kimi: winners of the fancy dress category at the show
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The other loves of Tammy’s life are her partner and fellow horse enthusiast, Henry van Dyk, her three horses, Guinney, Kimi and Fudge, and her three-month-old Labrador puppy called Judo. Home to humans, horses, dogs and cats is a smallholding in Honeydew, where Tammy and Henry train their horses.
Kimi, a thoroughbred former racehorse, is her companion at eventing, where Tammy puts him through his paces in two-day equestrian triathlon events. This includes show jumping, dressage and cross country. “We trained for the Winter Classic at the end of June and will keep it up for the Horse & Hound in July,” she confides.
Guinney is an ‘interesting’ mare that is currently in training, while Fudge, the pony, can be found on Saturdays with small people on her back at parties and riding classes.
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