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Title
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Toward the detection of landscape features : clustering 3D points using spatial and thematic characteristics
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Creator
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Romero, Boleslo Edward
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Date
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2010
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Collection
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Electronic Theses & Dissertations
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Description
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ABSTRACTTOWARD THE DETECTION OF LANDSCAPE FEATURES:CLUSTERING 3D POINTS USING SPATIAL AND THEMATIC CHARACTERISTICSByBoleslo Edward RomeroThe study of Geography generally concerns phenomena at or near the surface of the earth. High resolutions of 3D quantitative and qualitative data can represent such phenomena as objects or fields. The data can be grouped to reveal representations of contiguous regions of spatial and thematic homogeneity. My thesis is concerned with finding groups of 3D...
Show moreABSTRACTTOWARD THE DETECTION OF LANDSCAPE FEATURES:CLUSTERING 3D POINTS USING SPATIAL AND THEMATIC CHARACTERISTICSByBoleslo Edward RomeroThe study of Geography generally concerns phenomena at or near the surface of the earth. High resolutions of 3D quantitative and qualitative data can represent such phenomena as objects or fields. The data can be grouped to reveal representations of contiguous regions of spatial and thematic homogeneity. My thesis is concerned with finding groups of 3D points with similar locations, spatial relationships, and thematic values of spectral reflectance. To accomplish this successfully, I synthesized elements of two geographic theories: point aggregation from cartographic generalization and hierarchical geographic ontology. My experimental design used synthetic 3D point data with spectral values. I employed the multi-dimensional Mean Shift clustering technique from the discipline of Computer Vision, and adapted a 3D range image segmentation accuracy assessment technique. I also contributed new techniques for segmentation quality assessment including two area under the curve indices and the development of new segmentation surface plots. Experimental evaluations included comparisons of the Mean Shift results with K-means clustering results, spatial resolution results, noise evaluation results, and the results of an alternative color configuration. I modified the variable sets to address uneven lighting conditions and employed the experimental methods to grouping real-world terrestrial LiDAR scan data. Though my new spatial relationship variable needs improvement, the methods yielded groups of points representing features in the LiDAR data and provided evidence of the potential for grouping richly attributed 3D points that represent geographic features.
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Title
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Measuring the utility of color ramps in earth system science disciplines : a study of continuous data symbology
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Creator
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Steffke, Christy L.
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Date
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2015
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Collection
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Electronic Theses & Dissertations
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Description
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This study seeks to determine the efficacy of communicating information in continuous value maps using Earth system science visualizations in the digital environment. The research approach consisted of two parts. First, we investigated commonly-used color ramps employed across many disciplines and devised a method to test color ramp efficacy at conveying information from continuous data maps. A Continuous Data Model (CDM) was developed for use in both studies by manipulating a digital...
Show moreThis study seeks to determine the efficacy of communicating information in continuous value maps using Earth system science visualizations in the digital environment. The research approach consisted of two parts. First, we investigated commonly-used color ramps employed across many disciplines and devised a method to test color ramp efficacy at conveying information from continuous data maps. A Continuous Data Model (CDM) was developed for use in both studies by manipulating a digital elevation model (DEM), a common geology data construct used in a variety of visualizations and data models for analyzing and displaying topographic data. The resulting CDM was symbolized using four pervasive color ramps and used to derive 16 images from which participants estimated data values. Participants ultimately estimated values at four known map locations on four renditions of the same map. The only variable between participant estimations was the color scheme by which the maps were symbolized. Significant differences in color ramp performance were assessed using participant absolute data estimation differences from known map values as a function of the color ramp used for symbolization. Two methods for data collection were employed to provide information not only on how map readers estimate map values but also how they interact with continuous data maps. The participant-map interaction study included interaction variables that were collected using eye tracking technology and summarized using GIS. Our findings suggest that color ramps commonly used to depict ESS phenomena are not equally effective at communicating continuous map data.
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