Least Cost Path Analysis (LCPA) is a GIS-based approach for calculating the most efficient route between a start and end point, often in terms of shortest time or least amount of energy. The approach is often applied in archaeology to estimate locations of sites, and routes between them. We applied LCPA to estimate how sites in the Andes in the eastern portion of the Inka empire may have connected to sites in the western Amazon Basin. Our approach further used the known Inka Road network to test performance of two types of LCP models (linear vs. areal calculation) and four types of cost functions. LCPs can be calculated with an areal approach, where each cell of the DEM is given one overall slope value, or linearly, where the direction of travel across a cell affects the slope value. Four different algorithms were tested: Tobler's Hiking Function (1993), Tobler's Hiking Function with a vertical exaggeration of 2.3 based on human perceptions of slope (Pingel 2010), Pingel's empirical estimation approach (2010), and Pandolf et al.'s energy expenditure equation (1977) using both an areal and linear approach for all the algorithms. An initial study was conducted in the Cusco region and results were compared to the Inka Road network using the linear accuracy assessment method of Goodchild and Hunter (1997) and Güimil-Fariña and Parcero-Oubiña (2015). The findings suggest that the empirical estimation and caloric cost methods were the most accurate and performed similarly, both were more accurate than travel-time based costs, and linear methods were better than areal based methods when using higher resolution DEM inputs. / Master of Science / Least Cost Path Analysis (LCPA) is a method used for determining the most efficient route between a start and end point, often in terms of shortest time or least amount of energy. The approach is often applied in archaeology to estimate locations of sites, and routes between them. We applied LCPA to estimate how sites in the Andes in the eastern portion of the Inka empire may have connected to sites in the western Amazon Basin. Our approach further used the known Inka Road network to test performance of two types of Least Cost Path (LCP) models (linear vs. areal calculation) and four types of cost functions. LCPs can be calculated with an areal approach, where each cell in an elevation dataset is given one overall slope value, or linearly, where the direction of travel across a cell affects the slope value. Four different ways of calculating cost were tested: Tobler's Hiking Function (1993) using time as a cost, Tobler's Hiking Function with a vertical exaggeration of 2.3 where the cost is based on human perceptions of slope (Pingel 2010), Pingel's empirical estimation approach (2010) based on the preexisting Inka Road system, and Pandolf et al.'s energy expenditure equation (1977). All four ways of calculating costs were used both an areal and linear approach. An initial study was conducted in the Cusco region and results were compared to the Inka Road network by seeing what percent of each LCP was within 500 m of the Inka Road. The findings suggest that the empirical estimation and energy based methods were the most accurate and performed similarly, both were more accurate than travel-time based costs, and linear methods were better than areal based methods when using higher resolution elevation data inputs.

Between 1988 and 1989, an intensive archaeological survey of a small drainage known as Roan Mare coulee in southern Saskatchewan was conducted by Dr. Ernest Walker (Walker 1990). Among the 120 archaeological sites in the area, seven bison kills and a vast array of associated drivelines were identified. This study focuses upon the spatial interaction amongst the kills, the drivelines and the local environment in relation to the bison hunting strategies used on the Northern Plains. This is done by modelling where bison are likely to move in the terrain as well as how the topography obstructs their line of sight. As this problem covers a large spatial area and multiple different data sources, Geographic Information Systems (GIS) are integrated into the research design in the form of Least Cost Path and Viewshed analyses. Both archaeological data from Walker's survey and environmental data such as elevation and water sources served as the input datasets required by ArcGIS's spatial analysis tools. The results of the Least Cost Path analyses were compared visually to both the location and orientation of the driveline evidence, while the viewshed results were compared to the trap's location at the valley edge. The results of this research showed that the drivelines found at Roan Mare coulee appear to be following the general orientation of the landscape at the broadest scales, and likely served to funnel bison over large distances. There also appear to be several locations on the landscape that are amenable to moving bison to several different sites. The viewshed evidence shows the smaller scale nuances between bison vision and the terrain in a hypothetical drive event. The differences in the viewable area available to the bison at each site likely played a role in the chosen strategy employed when that site was used. It is hoped that this style of research can be continued with higher quality data and additional variables to help clarify many of the subtleties found in a Plains bison drive.

In the process of urbanization, the population and economy are rapidly growing. To achieve the demand of urbanization, natural areas are developed into construction areas in the city. Nature areas began to shrink and fragment, causing a great deal of damage, such as species extinction. The ability of nature to control the flood, adjust the rain, and filter pollution has been lost. This study is based on the city of Kaohsiung and Kaohsiung County. The study uses a large scale to re-examine the spatial structure of this area to propose an effective and reasonable planning policy for the environment and ecosystem. The study introduces the concept of green infrastructure to develop a green network system for the city. Green infrastructure is a network connecting natural areas and open spaces that can save ecological value and retain the ecosystem function. A green infrastructure network consists of hubs and links, and the network pattern can be made for different purposes. The study chose green land with an area of more than twenty hectares for the hubs and chose the terrestrial animal for the target species. The study uses the least-cost path analysis to plan the links for the terrestrial animal. The least-cost path, which is the path of least resistance when the terrestrial animal passes through the landscape. All the hubs generated 903 links. To create the green infrastructure networks, this study uses the gravity model to evaluate which corridor is the most important. Using the graph theory, the study developed three plans for a green infrastructure network to meet different demands: the Paul Revere, Traveling Salesman, and Least Cost to User networks. Planners can see different demands dictating the choice between different green infrastructure networks. Finally, the study discusses the three-network structure, finding the important hubs and links for the terrestrial animal. These areas should be protected to maintain the green infrastructure network.

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The construction of dams and hydro-power stations are some of the most common anthropogenic changes of watercourses and rivers. While being important to humans and society by providing electricity, these obstructions of watercourses can have severe consequences for the aquatic ecosystems. One consequence is that dams often hinder the important movement of migrating fish species between habitats. This can lead to decline and even extinction of important fish populations. To prevent these negative effects, a number of different fish passage systems, including nature-like fishways, have been developed. Nature-like fishways mimic natural streams in order to function as a natural corridor for a wide range of species. Planning and construction of a nature-like fishway is a complex task that often involves many different interests. In the present study a combination of multi-criteria decision analysis and least-cost path analysis is used for determining the best location for a nature-like fishway past Strömdalen dam in Gavleån, Sweden. An anisotropic least-cost path algorithm is applied on a friction-layer and a digital elevation model, and the least-cost path for a nature-like fishway is determined. The results show that the method is useful in areas of varying topography and steep slopes. However, because low slope is a very important factor when constructing a nature-like fishway, slope becomes the dominating factor in this analysis at the expense of e.g. distance to roads. Combining the methods with results from biological studies of fish behavior and detailed hydrological modelling would provide a very strong tool for the planning of nature-like fishways.

The objective of this research was to determine the environmental and social factors that led to the shift of settlement patterning from agro-pastoral in the late Neolithic to hillort sites at the turn of the Early Bronze Age and why burial mounds (tumuli) were erected further than anticipated from corresponding hillort sites in the Shkodra Plain region in Northern Albania. Geospatial techniques were used to examine 168 tumuli and seven hillort sites. These were mapped to examine visibility, viewshed, slope, and potential prehistoric networks. Based on the landscape visibility GIS results, it was found that hillort sites and tumuli were part of an social landscape that thrived on trade. It was determinable that the shift of the social landscape was related to Northern trade routes and probable changes in paleo-lake levels. This new evidence provides insight to Albanian prehistoric culture and has implications to related studies in the Balkans.