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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Forntida färdvägar : En lägsta kostnadsanalys av mesolitiska boplatser i norra Norrland / Ancient travel routes : A Least cost path analysis of mesolithic settlements in northern Sweden

Lundqvist, Rasmus January 2022 (has links)
This bachelor thesis will, through a method study, make an overlook of hypothetical movement patterns and travel routes in northern Sweden between Mesolithic sites/settlements.The common interpretation of the early movement patterns of northern Sweden has been heavily based on waterways as travel routes. With the building of dams along the major rivers in northern Sweden since 1940s many sites have been found along these rivers. This thesis will explore alternative routes based on least cost path analyses and movement patterns over land.Through data of topographic elevation and the Least Cost Path tool through QGIS, hypothetical connections will appear between the sites. The hypothetical travel routes will be tested with data from the cultural register of Sweden to find sites with similar dating near the routes. Through this thesis connections between sites over a large area will test if people moved through these hypothetical routes.
2

Identification of barriers and least cost paths for autonomous vehicle navigation using airborne LIDAR data

Poudel, Om Prakash 21 August 2007 (has links)
In the past several years, the Defense Advanced Research Projects Agency (DARPA) has sponsored two Grand Challenges, races among autonomous ground vehicles in rural environments. These vehicles must follow a course delineated by Global Positioning System waypoints using no human guidance. Airborne LIDAR data and GIS can play a significant role in identifying barriers and least cost paths for such vehicles. Least cost paths minimize the sum of impedance across a surface. Impedance can be measured by steepness of slope, impenetrable barriers such as vegetation and buildings, fence lines and streams, or other factors deemed important to the vehicle's success at navigating the terrain. This research aims to provide accurate least cost paths for those vehicles using airborne LIDAR data. The concepts of barrier identification and least cost path generation are reviewed and forty-five least cost paths created with their performance compared to corresponding Euclidean paths. The least cost paths were found superior to the corresponding Euclidean paths in terms of impedance as they avoid barriers, follow roads and pass across relatively gentler slopes. / Master of Science
3

GIS based optimal design of sewer networks and pump stations

Agbenowosi, Newland Komla 11 June 2009 (has links)
In the planning and design of sewer networks, most of the decisions are spatially dependent because of the right of way considerations and the desire to have flow by gravity. This research addresses the application of combined optimization-geographic information system (GIS) technology in the design process. The program developed for the design uses selected manhole locations to generate the candidate potential sewer networks. The design area is delineated into subwatersheds for determining the locations for lift stations when gravity flow is not possible. Flows from upstream subwatersheds are transported to the downstream subwatersheds via a force main. The path and destination of each force main in the system is determined by applying the Dijkstra's shortest path algorithm to select the least cost path from a set of potential paths. This method seeks to minimize the total dynamic head. A modified length is used to represent the length of each link or force main segment. The modified length is the physical length of the link (representing the friction loss) plus an equivalent length (representing the static head). The least cost path for the force main is the path with the least total modified length. The design approach is applied to two areas in the town of Blacksburg, Virginia. The resulting network and the force main paths are discussed. / Master of Science
4

Least Cost Path Modeling Between Inka and Amazon Civilizations

Lewis, Colleen Paige 09 June 2022 (has links)
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.
5

Determining Impediments to Gene Flow in a Natural Population of Cornus florida L. Cornaceae, Using Integrative Landscape Genetic Techniques

Meadows, Crystal 01 January 2011 (has links)
This study examined the impact intervening environment has on gene flow in the insect pollinated understory tree, Cornus florida L., by combining GIS and landscape genetic techniques (Least Cost Path Analysis, Circuit Theory, and Conditional Genetic Distance). Traditional population genetic analysis indicated pair-wise relatedness was significantly correlated to distance (Pearson; r = -0.312, P < 0.001) suggesting a spatial component to offspring relatedness. Dispersal throughout the study site was non-random, exhibiting a high degree of pollen pool structure due to restricted gene flow (Two-Generation Analysis; Φft = 0.161, P = 0.001). Forest structure was quantified in GIS layers representing coniferous canopies, mixed hardwood canopies, C. florida canopies, open understory (roads), and open understory/canopy due to tree removal. Of these layers, landscape isolation for the roads layer provided the best-fit model for describing genetic differentiation among sampled pollen pools (Mantel; r = 0.542, P = 0.001). These data also suggest that improved biological inferences can be gained by examining a range of landscape isolation models.
6

GIS and Archaeology: Bison Hunting Strategies in Southern Saskatchewan

2013 June 1900 (has links)
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.
7

Green Infrastructure Establishment:Case Study of Kaohsiung County and Kaohsiung City

Hsu, Zheng-Yang 08 September 2011 (has links)
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.
8

Habitat linkages and highway mitigation using spatially-explicit GIS-based models

Jones, Andrew Charles 13 December 2012 (has links)
I identified suitable locations for highway wildlife crossing mitigations across the TransCanada Highway (TCH) in the area of Mount Revelstoke and Glacier National Park (MRGNP), British Columbia. Highways fragment natural landscapes leading to habitat loss, reduced ecosystem connectivity and direct wildlife mortality though motor vehicle collisions. Grizzly bears (Ursus arctos) are vulnerable to the effects of habitat and population fragmentation. Highway wildlife crossing mitigations improve ecosystem connectivity by increasing the permeability of transportation corridors to wildlife. I identified high-quality habitat patches using a resource selection function (RSF) based on 1,703 radio telemetry locations from 59 grizzly bears. Least-cost path analysis (LCP) among habitat patches identified 6 linkage zones across the TCH. Electric circuit theory was used to generate current maps that classify linkage zones as high-volume crossing areas or tenuous linkages. Linkage zones occurred where high-quality habitat aligned with physical features conducive to cross-valley wildlife dispersal.
9

DISPERSAL BEHAVIOR OF WHITE-TAILED DEER IN AN AGRICULTURAL LANDSCAPE

Springer, Matthew Thomas 01 May 2017 (has links) (PDF)
White-tailed deer (Odocoileus virginianus) dispersal and excursion movements impact gene flow, population dynamics, and disease spread. Knowledge of movement characteristics and habitat selection during dispersal could provide the ability to predict how deer may relocate themselves within the landscape while providing managers valuable information regarding corridors for gene flow and disease spread. My objectives were to 1) test the hypothesis that extra-home-range movements occur as a strategy to broaden mating opportunities or as a means of searching for higher quality resources in this fragmented landscape, 2) compare occurrence rates and path movement metrics for dispersal and excursion movements to determine if underlying differences in behavior exist that would allude to mechanisms for accepting the risk of leaving a home range, 3) create and test the performance of expert opinion and step selection function resistance models at predicting deer dispersal movements, and 4) fit single and multiple random walk models to dispersal path data to determine movement states occurring within this behavior. During 2011-2014, I placed GPS collars programmed to take hourly locations on 49 fawn and yearling white-tailed deer in agricultural east-central Illinois to record dispersal and excursion movement paths. Linear mixed effects models were used to test for differences in path characteristics between sexes and ages (e.g., distance, straightness, duration, and speed). I used known-fate models, with demographic, temporal, and home range variables as covariates, to obtain dispersal and excursion occurrence rate estimates. Ten dispersal and 54 excursion movement paths were recorded during the study. Dispersal paths were longer and straighter (P < 0.001), and trended toward being longer in duration (P = 0.080) and faster in speed (P = 0.085), than excursion paths. Dispersal rates differed by sex (annual estimate ± SE with ages pooled: males 0.81 ± 0.12, females 0.16 ± 0.15) and were greatest during the breeding season (14-day estimates for males: winter 0.00 ± 0.01, fawning 0.02 ± 0.1, prebreeding 0.01 ± 0.01, and breeding 0.31 ± 0.15, and females: winter 0.00 ± 0.01, fawning 0.01 ± 0.1, prebreeding 0.01 ± 0.01, and breeding 0.04 ± 0.03). In contrast, I found no evidence that excursion rates were influenced by demographic, temporal, or home range variables (annual: 0.78 ± 0.06). I compared 2 methods of resistance modeling for predicting deer dispersal paths. I created an expert opinion survey and calculated a dispersal step selection function (SSF) to rank habitat variables and create 2 types of resistance maps to dispersal movements. I created least-cost paths with the starting and ending points coinciding with recorded dispersal paths within these 2 resistance maps. I compared the created paths to actual paths and a null straight line path using a path deviation index (PDI), path straightness, and path cost/m as variables of interest. Experts ranked land cover variables differently by season, applying a lower resistance value to agriculture cover during the summer/fall period, so 2 versions of the expert opinion resistance maps were created. For the SSF, I found that both forest cover and streams had significant nonlinear effects on deer dispersal movements. Assuming that all other factors remained constant, deer were more likely (≥ 0.50 probability) to move toward forested habitat when located < 335 m and when > 2795 m away. Deer dispersal movement behavior relating to streams followed a similar trend but with deer always having > 0.56 probability to move toward a stream than away. For least-cost path comparison, I conducted 3 ANOVAs (α = 0.05 throughout) to test for mean differences in calculated path metrics for all paths with path type as a within-subjects effect. I found no difference between the expert opinion survey model, the SSF model, and the null straight line model at predicting dispersal paths. PDI values were similar among all models (F1,9 = 0.004, P = 0.99). The SSF paths (0.91 ± 0.02) were significantly straighter then both the expert opinion (0.57 ± 0.03) and actual deer paths (0.44 ± 0.06; F1, 9 = 32.65, P < 0.001), but the expert opinion path did not differ from the actual path (P = 0.08). Path costs differed within the expert opinion survey resistance map (F1, 9 = 14.21, P < 0.001) with the expert opinion least cost paths (23.64 ± 3.14) having lower resistance/m than both the actual (46.15 ± 3.85) and straight line paths (48.74 ± 3.94; P < 0.001 for both). However, the actual and straight line paths did not differ (P = 0.872). There were no difference in path costs between the actual, SSF least-cost path, and straight line paths within the SSF resistance map (F1, 9 = 0.454, P = 0.64). I constructed and attempted to fit single and multiple random models to collected dispersal locations using WinBUGS v. 1.4.3. I was able to fit a single random walk model to deer dispersal paths but the more complex random walk models did not converge. I used the average parameter values derived from the single model to simulate deer dispersal paths and compared them to observed Net Squared Displacement. My simulated paths underpredicted deer displacement for 0.90 of individuals. Deer in east-central Illinois are very mobile and commonly make excursion movements throughout the year. The fact that I recorded differing dispersal rates within the same study area over a temporally short period from a previous study highlight the need for managers to obtain recent estimates of population parameters when making management decisions. The frequency of excursion movements should not be overlooked by managers as it is a behavior that can influence gene flow and potentially spread disease across the landscape at a localized scale. The preference for forest and stream habitats during dispersal can allow managers to focus surveillance or culling efforts around these types of habitats. The application of the least-cost path modeling technique appears to be ineffective at predicting deer dispersal paths, which emphasizes the importance of validating these types of models with actual data. The results from the random walk analysis highlight the need to collect as many locations as possible during temporally-short movements to understand the mechanisms acting upon them.
10

Spatial Relationships of Sacred and Secular Spaces of the Hopewell and Adena People, Muskingum River Valley, Ohio

Klein, Sabrina J. 17 September 2015 (has links)
No description available.

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