The Appalachian National Scenic Trail is a unit of the National Park System created by the National Trails Act of 1968. Commonly referred to as the Appalachian Trail, or the AT, this National Park has some of the longest boundaries of any park. The AT is routed more than 2000 miles along the mountains of the eastern United States. The land purchased for the protection of the AT creates a separate boundary on each side of the trail. Monitoring these boundaries for intrusions or encroachments is a difficult and time-consuming task when done totally by field methods. This thesis presents a more efficient and consistent monitoring process using remote sensing data and change detection algorithms. Using Landsat TM images, Normalized Difference Vegetation Index (NDVI), and image difference change detection, this research shows that major boundary encroachments can be detected. Detection of sub-pixel vegetation index decreases identifies specific locations for field inspection. Assuming low cost multispectral Landsat imagery is available, simple NDVI difference calculation allows this technique to be applied to the entire AT one or more times per year. This procedure would improve the response time for encroachment mediation. The producer's accuracy for finding possible encroachments was 100 percent and the consumer's accuracy for possible encroachments indicated was 78.3 percent. Due to limited image availability, this study only examines change between one pair of Landsat images. Further refinement of these techniques should investigate other Landsat images at other times. Use of other remote sensing systems and change detection algorithms could be the focus of further research. / Master of Science

Thesis (LLD (Private Law))--University of Stellenbosch, 2010. / Bibliography / ENGLISH ABSTRACT: South African courts seem to be adopting a new approach to the problem of building encroachments. For pragmatic and policy reasons courts are now inclined to exercise its discretion in favour of leaving building encroachments in place, against compensation, despite the common law right to demand removal. It has been widely accepted that courts indeed have the discretion to award damages instead of removal of the building encroachment. However, the circumstances involved and the consequences of these orders are uncertain and hence these orders result in confusion. It is unclear how this discretion is exercised. Furthermore, it is uncertain whether this discretion includes the power to order transfer of the encroached-upon land to the encroacher. There are doctrinal and constitutional implications that may be triggered by these court orders that leave building encroachments in place. The doctrinal issues centre on what happens when an encroachment is not removed and nothing is said about the rights of the respective parties after the order is made. Possible solutions are investigated to provide a doctrinally sound outcome in encroachment disputes. It is clear that the encroacher is allowed to continue occupying the portion of property on which the encroachment is erected. It seems as though a use right is indirectly created when the encroachment remains in place. The constitutional difficulty lies in the fact that the court orders may result in infringements that conflict with section 25 of the Constitution. The focus is specifically to determine whether these orders result in the compulsory loss of property or property rights. With reference to Germany, the Netherlands and Australia, a comparative perspective is provided in order to support the doctrinal and policy arguments. The comparative law provides a source of guidelines for what may work effectively and informs the ultimate suggestion of this project, namely the need for legislation to regulate building encroachments in South Africa. The legislation envisaged would have to prescribe with at least some sort of certainty how and in which circumstances the discretion should be exercised. It should also provide clarity with regard to the right that is created when the encroachment is not removed and how the compensation that is awarded in exchange for removal, should be determined. The unnecessary confusion and uncertainty that result from court orders made in the context of building encroachments may be cleared up by legislation. / AFRIKAANSE OPSOMMING: Suid Afrikaanse howe begin al hoe meer om ‘n nuwe benadering te volg ten opsigte van oorskrydende bouwerke. Dit lyk asof howe meer geneig is om hul diskresie uit te oefen ten gunste daarvan om die oorskryding vir pragmatiese en beleidsredes teen vergoeding in stand te hou, ten spyte van die gemeenregtelike reg om verwydering te eis. Daar word algemeen aanvaar dat howe wel die diskresie het om in die konteks van oorskrydende bouwerke skadevergoeding toe te ken in plaas van verwydering. Die omstandighede betrokke by en die nagevolge van hierdie beslissings is egter onseker en daarom lei dit tot verwarring. Dit is nie altyd duidelik hoe hierdie diskresie uitgeoefen word nie. Daarbenewens is daar ook onsekerheid oor of die diskresie die bevoegdheid insluit om oordrag van die grond waarop die oorsrkryding staan, te gelas. Die beslissings kan ook doktrinêre en grondwetlike implikasies hê. In terme van die doktrinêre probleem is daar vrae oor wat gebeur as die oorskryding nie verwyder word nie en niks word gesê oor die regte van beide partye in die dispuut nie. Oplossings word ondersoek om die beste moontlike doktrinêre verduideliking te probeer vasstel. Die eienaar van die oorskrydende bouwerk mag voortgaan om die grond waarop die oorskryding staan te okkupeer. Dit lyk asof ‘n gebruiksreg indirek geskep word ten gunste van die oorskryder wanneer die oorskryding nie verwyder word nie. ‘n Grondwetlike probleem mag veroorsaak word deur die moontlike oortreding van artikel 25 van die Grondwet. Die beslissings mag lei tot die gedwonge verlies van grond of regte, wat aan die vereistes van artikel 25 moet voldoen. ‘n Vergelykende perspektief met verwysing na Duitsland, Nederland en Australië word verskaf om die doktrinêre en beleidsargumente te ondersteun. Die vergelykende reg bied ‘n bron van riglyne vir wat effektief kan werk en het dus die wetgewing wat in hierdie proefskrif voorgestel word geïnspireer. Die wetgewing wat beoog word sal moet voorskryf hoe en onder watter omstanghede die diskresie uitgeoefen moet word. Dit moet ook sekerheid gee ten opsigte van die reg wat geskep word as die oorskryding nie verwyder word nie en hoe die skadevergoeding bepaal moet word. Die onnodige verwaring en onsekerheid wat veroorsaak word deur hierdie hofbeslissings kan opgeklaar word deur die promulgering van wetgewing om oorskrydende bouwerke te reguleer.