Remote Sensing Commons^™

Identifying The Drivers Behind The Decline Of Douglas-Fir And True Fir Species In Sw Oregon, Alexander Bryant Bentley

Dissertations and Theses

Increased levels of Pseudotsuga menziesii (DF) and Abies species (TF) decline throughout dry forests in the Klamath Mountains and Western Cascades ecoregions have been recorded in recent years, with preliminary evidence suggesting that factors influenced by changing climatic conditions and encroachment from fire suppression policies are primarily to blame. Yet, the physiological and environmental mechanisms of drought-driven tree decline are poorly understood across biophysical and spatial gradients. Given the complex relations that drive decline, determining the degree of influence of specific drivers is difficult, creating unique challenges for modern forest management. To elucidate the most important factors driving DF and …

Uncovering The Dynamic Nature Of Fire Refugia Across Landscapes In Oregon's Western Cascades, Alec Scott Dyer

Dissertations and Theses

With increased fire activity, the presence of fire refugia is critical to support forest resiliency and mitigate large-scale vegetation conversion, however, the persistence of fire refugia within burn perimeters over time is uncertain. This study examines the dynamic nature of fire refugia by mapping the decline in forest cover over time, identifying spatiotemporal patch- and landscape-scale patterns and the biophysical drivers of delayed mortality following the 2020 Labor Day Fires occurring in Oregon’s western Cascades. After three years post-fire, delayed mortality accounted for an additional 8.5% of forest loss (total of 24,147 hectares in all five burns) compared to pre-fire …

Structure-From-Motion Derived Snow Cover In Burned Forests Of The Western Oregon Cascades, Siobhan Ciafone

Dissertations and Theses

Forest fire occurrence in the western US has increased rapidly since the 1980s, and most western US fires occur in the seasonal snow zone. Burned forests influence snow accumulation and melt patterns for years following fire, and understanding drivers of variability in snow cover across a burned landscape at the basin-scale is necessary for accurate hazard prediction and water resource forecasting. Basin-scale surveys of snowpack are possible with remote sensing, but accurate sensing methods such as Light Detection and Ranging (LiDAR) are often cost-prohibitive. In the last decade, structure-from-motion (SfM), an optical remote sensing technique, has emerged as an affordable …

Heat Mapping Crime: A Data-Driven Approach To Policing In New York, Beruktawit Gebreamlak, Daniel Ochoa

altREU Projects

In the aftermath of the COVID-19 pandemic, New York City has seen a surge in criminal activities. In 2023, major crime continues to be higher compared to pre-pandemic levels. Although progress is being made to reduce the number of murders and robberies, law enforcement is continuing to struggle with increases in felony assaults and car thefts. Our project serves to benefit members of the community and law enforcement alike. We created a heat map, which is a visual representation of data that uses colors to represent different values. In the context of crime mapping, our heat map is used to …

Assessment Of Vertical Accuracy From Uav-Lidar And Structure From Motion Point Clouds In Floodplain Terrain Mapping, Andrew Muller

Dissertations and Theses

Remote sensing technologies are being applied to a variety of uses because of the increase in access to various products (digital sensors, UAVs, software) and its ability to model relatively large areas in a short amount of time. While these new technologies are beginning to be adopted, validation of their merit in floodplain terrain mapping is lacking. The main goal of this study is to evaluate the vertical accuracy of digital elevation models (DEMs) generated with UAV-based LiDAR and Structure from Motion (SfM), also known as photographic LiDAR or PhoDAR. Airborne (manned aircraft) LiDAR has been applied to river research …

Forest Fire Effects On The Temporal Variability Of Landscape Snow Albedo Relative To Burn Severity, Max Gersh

Dissertations and Theses

Snow-water storage is decreasing, while forest fires are increasing in duration, size, frequency, and intensity, due to climate change. Most forest fires occur in the seasonal snow zone, altering snow mass and energy balance for many years following fire. Following forest fires, Surface snow albedo (SSA) decreases, as light absorbing particles (LAP), particularly black carbon (BC) produced in forest fires get deposited throughout the snowpack, altering snowpack energy balance driving earlier snowmelt in burned forests. While SSA decreases, landscape snow albedo (LSA) increases following fire, as more of the snow-covered surface becomes visible beneath the burned forest canopy, brightening the …

Relationship Between Image Spectroscopy Spatial Resolution And Crown Level Tree Species Classification Accuracy, Andrew Richard Fritter

Dissertations and Theses

Hyperspectral imagery has become a common remote sensing data type used in tree species classifications because of its rich spectral signals that allow the detection of the variations in canopy reflectance. While high spatial resolution hyperspectral imagery provides fine spatial resolution for discerning surface objects, it has the inherent drawbacks of expensive acquisition costs, large data sizes, and can be computationally taxing to use. This study attempts to determine a relationship between crown level tree species classification accuracy and hyperspectral spatial resolution. Future tree species classification projects can make use of this relationship by targeting a spatial resolution that best …

Climatic Controls On The Kinematics Of The Hooskanaden Landslide, Curry County, Oregon, Kara Kingen

Dissertations and Theses

Slow-moving earthflows represent major sources of sediment transport and erosion and are problematic for the management of critical infrastructure. The Hooskanaden Landslide -- a slow-moving earthflow on the southwest coast of Oregon -- crosses US Highway 101 and has been a site of continued interest to the Oregon Department of Transportation (ODOT) due to the weak lithology, erosive environment, and recurrent surge behavior (every ~15 years). Past surges, including the most recent (2019), have occurred during the winter, suggesting that velocity changes are predominantly controlled by climatic inputs. To examine the response of the Hooskanaden Landslide to seasonal and other …

Evaluation Of Manual And Semi-Automated Deep-Seated Landslide Inventory Processes: Willapa Hills, Washington, Tiffany E. Justice

Dissertations and Theses

Recent advances in remote sensing data and technology have allowed for computational models to be designed that successfully extract landforms from the landscape. The goal of this work is to create one such semi-automated model to extract deep-seated landslides located in complex geomorphic terrain. This is accomplished using geographic object-based image analysis (GEOBIA) techniques, considered by leaders in the field of image analysis to have an advantage over traditional automated classification methods. GEOBIA methods can mimic human visual interpretation by including more characteristic features used to assess the relationship between image data and the ground surface such as color reflectance …

Pre-Emptive Detection Of Mature Pine Drought Stress Using Multispectral Aerial Imagery, Nancy Grulke, Jason Maxfield, Phillip Riggan, Charlie Schrader-Patton

Biology Faculty Publications and Presentations

Drought, ozone (O₃), and nitrogen deposition (N) alter foliar pigments and tree crown structure that may be remotely detectable. Remote sensing tools are needed that pre-emptively identify trees susceptible to environmental stresses could inform forest managers in advance of tree mortality risk. Jeffrey pine, a component of the economically important and widespread western yellow pine in North America was investigated in the southern Sierra Nevada. Transpiration of mature trees differed by 20% between microsites with adequate (mesic (M)) vs. limited (xeric (X)) water availability as described in a previous study. In this study, in-the-crown morphological traits (needle chlorosis, …

Lidar Predictive Modeling Of Kalapuya Mound Sites In The Calapooia Watershed, Oregon, Tia Rachelle Cody

Dissertations and Theses

Archaeologists grapple with the problematic nature of archaeological discovery. Certain types of sites are difficult to see even in the best environmental conditions (e.g., low-density lithic scatters) and performing traditional archaeological survey is challenging in some environments, such as the dense temperate rain forests of the Pacific Northwest. Archaeologists need another method of survey to assess large areas and overcome environmental and archaeological barriers to site discovery in regions like the Pacific Northwest. LiDAR (light detection and ranging) technology, a method for digitally clearing away swaths of vegetation and surveying the landscape, is one possible solution to some of these …

An Operational Drought Prediction Framework With Application Of Vine Copula Functions, Mahkameh Zarekarizi

Student Research Symposium

Early and accurate drought predictions can benefit water resources and emergency managers by enhancing drought preparedness. Soil moisture memory is shown to contain helpful information for prediction of future values. This study uses the soil moisture memory to predict their future states via multivariate statistical modeling. We present a drought forecasting framework which issues monthly and seasonal drought forecasts. This framework estimates droughts with different lead times and updates the forecasts when more data become available. Forecasts are generated by conditioning future soil moisture values on antecedent drought status. The statistical model is initialized by soil moisture simulations retrieved from …

Precipitation Intensity Trend Detection Using Hourly And Daily Observations In Portland, Oregon, Alexis Cooley, Heejun Chang

Geography Faculty Publications and Presentations

The intensity of precipitation is expected to increase in response to climate change, but the regions where this may occur are unclear. The lack of certainty from climate models warrants an examination of trends in observational records. However, the temporal resolution of records may affect the success of trend detection. Daily observations are often used, but may be too coarse to detect changes. Sub-daily records may improve detection, but their value is not yet quantified. Using daily and hourly records from 24 rain gages in Portland, Oregon (OR), trends in precipitation intensity and volume are examined for the period of …

Unmanned Aerial Vehicle Based Structure From Motion Biomass Inventory Estimates, Emily Jane Bedell

Dissertations and Theses

Riparian vegetation restoration efforts demand cost effective, accurate, and replicable impact assessments. In this thesis a method is presented using an Unmanned Aerial Vehicle (UAV) equipped with a GoPro digital camera to collect photogrammetric data of a 2.02-acre riparian restoration. A three-dimensional point cloud was created from the photos using Structure from Motion (SfM) techniques. The point cloud was analyzed and compared to traditional, ground-based monitoring techniques. Ground truth data collected using the status-quo approach was collected on 6.3% of the study site and averaged across the entire site to report stem heights in stems/acre in three height classes, 0-3 …

Use Of Water Indices Derived From Landsat Oli Imagery And Gis To Estimate The Hydrologic Connectivity Of Wetlands In The Tualatin River National Wildlife Refuge, Debra Sue Blackmore

Dissertations and Theses

This study compared two remote sensing water indices: the Normalized Difference Water Index (NDWI) and the Modified NDWI (MNDWI). Both indices were calculated using publically-available data from the Landsat 8 Operational Land Imager (OLI). The research goal was to determine whether the indices are effective in locating open water and measuring surface soil moisture. To demonstrate the application of water indices, analysis was conducted for freshwater wetlands in the Tualatin River Basin in northwestern Oregon to estimate hydrologic connectivity and hydrological permanence between these wetlands and nearby water bodies. Remote sensing techniques have been used to study wetlands in recent …

Comparing Unmanned Aerial Systems (Uas) Structure-From-Motion Digital Surface Modeling To Laser Imaging Detection And Ranging (Lidar), Joshua D. Schane

Geography Masters Research Papers

UAS (unmanned-aerial systems) mapping is an emerging technology in spatial science. UAS, more informally referred to as “drones,” are small, radio-controlled or autonomous aerial platforms outfitted with camera sensor systems that can be deployed to fly missions for mapping terrain and structures. With the use of a photogrammetry technique called structure-from-motion, overlapping aerial images can be developed into high-resolution spatial data (< 5-cm). These data are georeferenced by GPS location information assigned to aerial targets which act as ground-control points (GCPs). This research explores the accuracy of the UAS-derived digital surface model (DSM) as it relates to a LIDAR DSM of the same study area in St. Helens, Oregon.

The site that was chosen to be mapped was a large wastewater treatment plant, with surrounding natural areas, residential, and industrial properties. The site was mapped using a small quadcopter-style UAS which was programmed autonomously; the overlapping aerial …

Using Landsat Tm Imagery To Monitor Vegetation Change Following Flow Restoration To The Lower Owens River, California, Lesley Crandell Bross

Dissertations and Theses

Rehabilitating river corridors to restore valuable riparian habitat consumes significant resources from both governments and private companies. Given these considerable expenditures, it is important to monitor the progress of such projects. This study evaluated the utility of using Landsat Thematic Mapper remotely-sensed data from 2002 and 2009 to monitor vegetation change induced by instream flow restoration to the Lower Owens River in central California. This study compared the results of an unsupervised classification with an NDVI threshold classification to appraise the resources required and effectiveness of each analysis method. The results were inspected by creating standard remote sensing accuracy error …

Advances In Autonomous-Underwater-Vehicle Based Passive Bottom-Loss Estimation By Processing Of Marine Ambient Noise, Lanfranco Muzi

Dissertations and Theses

Accurate modeling of acoustic propagation in the ocean waveguide is important to SONAR-performance prediction, and requires, particularly in shallow water environments, characterizing the bottom reflection loss with a precision that databank-based modeling cannot achieve. Recent advances in the technology of autonomous underwater vehicles (AUV) make it possible to envision a survey system for seabed characterization composed of a short array mounted on a small AUV. The bottom power reflection coefficient (and the related reflection loss) can be estimated passively by beamforming the naturally occurring marine ambient-noise acoustic field recorded by a vertical line array of hydrophones. However, the reduced array …

A Geospatial Tool For Wetland Prioritization At The Watershed Scale, Debra Sue Blackmore, Heejun Chang

Institute for Natural Resources Publications

There is an increasing demand for assessing ecosystem functions for freshwater wetlands, especially when comparing or prioritizing among wetlands at the watershed scale. We estimated the relative potential of selected ecosystem functions for freshwater wetlands within a watershed using widely available geospatial data. We developed four functions to estimate 1) flood storage, 2) late season flow, 3) sediment retention and 4) temperature control in four pilot watersheds in Oregon (Tualatin, Coquille, Upper Grande Ronde and Sprague). These watersheds are geographically separated from each other representing diverse ecoregion environments. Spatial analysis and geographic information system (GIS) were designed for maximum re-use, …

The Cost Of Hauling Timber: A Comparison Of Raster- And Vector- Based Travel-Time Estimates In Gis, Sara M. Loreno

Geography Masters Research Papers

The cost of transporting forest products from harvest site to processing facility is a critical indicator of timber project feasibility. In order to accurately assess these timber haul costs, least-cost travel-time estimates among the site and the facility can be estimated using vector- or raster-based GIS methods. This study explores the applicability of both the raster- and vector-techniques within a variety of landscapes, including forested areas where comprehensive transportation data is limited. A comparison between the travel-time estimates derived from both methods was performed on three study sites using real-world data. The comparison also tested the effect of resolution on …

Modeling Acoustic Scattering From The Seabed Using Transport Theory, Jorge Quijano, Lisa M. Zurk

Electrical and Computer Engineering Faculty Publications and Presentations

Radiative Transfer (RT) theory has established itself as an important tool for electromagnetic remote sensing in parallel plane geometries with random distributions of scatterers, and most recently it has also been proposed as a model for the propagation of elastic waves in layered ocean sediments. In this work the capabilities of this model are illustrated, as the RT method is used to predict backscattering strength from laboratory models of random media. The RT model is characterized by its flexibility on accommodating scatterers in a broad variety of sizes, shapes, and acoustic contrast relative to the background media. Additionally, this formulation …

Western Juniper (Juniperus Occidentalis) Ecology With An Exercise In Remote Sensing Techniques, Elizabeth A. Goralski

Geography Masters Research Papers

Western juniper (Juniperus occidentalis var. occidentalis) has been expanding its biogeographic range since the mid-1800's, resulting in decreased biodiversity, altered wildlife habitat, increased soil erosion, reduced stream flows and reduced forage production. The direct causes of western juniper aforestation are unclear but appear to be related to altered fire regimes, over grazing, and climatic shifts.

This study seeks to determine how Landsat images combined with Digital Orthoquads (DOQs) can be used to examine the geographic distribution of western juniper. Satellite imagery has yet to be applied to the large scale mapping of western juniper aforestation, resulting in the lack of …

"Sustainable Development": Critical Concepts In Geography, Tyler Vick

Geography Masters Research Papers

This paper reviews significant geographic contributions to academic literature in the arenas of conservation, environmental thought, and "sustainable development", in order to understand why geographers have not been more central contributors to the sustainable development movement. A review of geographic literature reveals no lack of understanding on the "sustainable development" concept. However, the disciplines' contributions are lacking in numbers relative to published articles and in developing research and practical methods for directly benefiting the "sustainable development" movement. In fact, only a handful of geographers have made multiple literary contributions on the topic of "sustainable development."

The discipline of geography is …

Methods For Correcting Topographically Induced Radiometric Distortion On Landsat Thematic Mapper Images For Land Cover Classification, David Michael Rosen

Geography Masters Research Papers

Satellite imagery is commonly used to study land-use, land-cover change in mountainous areas. Classification of land-cover types is particularly difficult in this type of terrain because topography affects the spectral response of surface features. Several techniques have been developed to help compensate for this topographic effect and to increase classification accuracy.

The purpose of this study is to compare topographic correction methods to determine which produces the most accurate results. Method 1 does not use any topographic correction, serving as a control. Method 2 is based on the Lambertian model, and uses topographical data as variables in an equation. Method …

Comparing Twenty-Four Years Of Forest Change In Two Communities Of Mexico's Meseta PuréPecha Using Multi-Spectral Satellite Imagery, Kevin Scott Martin

Dissertations and Theses

The Meseta Purépecha, a volcanic plateau in the Mexican state of Michoacan, is home to one of the most species-rich pine forests in the world. Recent increases in demand for forest products has put added pressure on these resources. Though existing research has suggested significant deforestation in the Meseta, there is little information identifying specific areas of decline. This study focuses on two indigenous communities in the Meseta--Pichátaro and Sevina. Both communities have long relied on wood as an economic resource. However, the two communities have reacted differently to increased demand for forest resources. The purpose of this study is …

Gis Enhancements Using Gps Technology, Marc R. Beckel

Dissertations and Theses

Global Positioning System (GPS) technology is a viable tool for the collection and creation of Geographic Information System (GIS) databases. Organizations have turned their attention to using this tool to develop new databases for their existing GIS. The integration of these new GPS derived databases with older existing databases leads to both technical and organizational repercussions. With the integration of GPS derived data, an organization's existing GIS requires enhancements to GIS databases and the organization must be prepared to manage the integration.

This thesis examines the technical issues that occur due to integration and conflation of GPS data in an …