Open Access. Powered by Scholars. Published by Universities.®

Social and Behavioral Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Geographic Information Sciences

Portland State University

Theses/Dissertations

Geographic information systems

Articles 1 - 8 of 8

Full-Text Articles in Social and Behavioral Sciences

The Impact Of Climate Change On Selected Pnw Watersheds Through The Lens Of Western Red Cedar Habitat, Jordan T. Hamann Jul 2023

The Impact Of Climate Change On Selected Pnw Watersheds Through The Lens Of Western Red Cedar Habitat, Jordan T. Hamann

Dissertations and Theses

Climate change is a real phenomenon that is exacerbating existing natural processes and developing into a new normal for the planet. This change may be devastating for Pacific Northwest populations of Western Red Cedar (WRC) west of the Cascade Mountain range in the states of Oregon and Washington. WRC is a valuable tree species for reasons both economic and cultural. Dieback among WRC is following an accelerating trend. Since dieback is usually followed by tree mortality, understanding its causes and distribution is beneficial to the overall success of the species going into the future.

Through the use of ESRI's ArcGIS …


Assessment Of Vertical Accuracy From Uav-Lidar And Structure From Motion Point Clouds In Floodplain Terrain Mapping, Andrew Muller Dec 2021

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 …


Homelessness In Portland, Oregon: An Analysis Of Homeless Campsite Spatial Patterns And Spatial Relationships, Krystle N. Harrell May 2019

Homelessness In Portland, Oregon: An Analysis Of Homeless Campsite Spatial Patterns And Spatial Relationships, Krystle N. Harrell

Geography Masters Research Papers

Homelessness is a complex American social issue. Understanding the homeless population, including how many people experience homelessness, how they entered the experience, their demographics, how they survive, and where they survive, aids policymakers, planners, and advocates in developing the appropriate approaches and solutions to end and prevent homelessness. Analysis of homeless spatial patterns and distributions across different locales provides a more in-depth understandings of this population and how best to support them, from the local to national level. Using geographic information systems (GIS) and statistical methods, this study examines the spatial patterns of homeless campsites and their relationship with urban …


Assessing Ppgis Usability And Its Relationship To Spatial Data Production: A Case Study, Timothy Michael Hitchins Sep 2018

Assessing Ppgis Usability And Its Relationship To Spatial Data Production: A Case Study, Timothy Michael Hitchins

Dissertations and Theses

Modern Geoweb-enabled PPGIS methodologies incorporate interactive map applications as the main driver for public engagement and data collection. However, little research explores exactly how the public interact with these applications to produce spatial data, a fact that contributes to criticisms of final data quality. Usability evaluation offers a solution for developing better PPGIS data production systems by identifying problems in the application interface for which the public engage. Drawing on a case study example of a PPGIS application developed to collect socio-spatial data from members of a random public, this paper addresses usability in a three-stage approach. First, controlled experimentation …


Gis Spatial Analysis Of Arctic Settlement Patterns: A Case Study In Northwest Alaska, Justin Andrew Junge Sep 2017

Gis Spatial Analysis Of Arctic Settlement Patterns: A Case Study In Northwest Alaska, Justin Andrew Junge

Dissertations and Theses

In northwest Alaska, archaeologists hypothesize that environmental variability was a major factor in both growing coastal population density, with large aggregated villages and large houses, between 1000 and 500 years ago (ya), and subsequent decreasing population density between 500 ya and the contact era. After 500 ya people are thought to have dispersed to smaller settlements with smaller house sizes in coastal areas, and perhaps, upriver. This settlement pattern was identified through research at four site locations over 30 years ago. The changing geographic distribution of sites, associated settlement size, and house size has not been examined in detail. A …


Using Gist Features To Constrain Search In Object Detection, Joanna Browne Solmon Aug 2014

Using Gist Features To Constrain Search In Object Detection, Joanna Browne Solmon

Dissertations and Theses

This thesis investigates the application of GIST features [13] to the problem of object detection in images. Object detection refers to locating instances of a given object category in an image. It is contrasted with object recognition, which simply decides whether an image contains an object, regardless of the object's location in the image.

In much of computer vision literature, object detection uses a "sliding window" approach to finding objects in an image. This requires moving various sizes of windows across an image and running a trained classifier on the visual features of each window. This brute force method can …


The Cost Of Hauling Timber: A Comparison Of Raster- And Vector- Based Travel-Time Estimates In Gis, Sara M. Loreno Jan 2014

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 …


Gis Address-Matching And Transportation Analysis, James D. Orrell Aug 1990

Gis Address-Matching And Transportation Analysis, James D. Orrell

Dissertations and Theses

Geographic Information System (GIS) address-matching combined with other GIS processing offers new analytical opportunities in the area of transportation planning and analysis. Address-matching, an automated method for generating geographically-referenced (geocoded) point locations on a map from common tabular databases, can facilitate transportation analysis by providing a planning tool based on individual rather than aggregated spatial distributions more common to transportation issues.

This thesis presents a case study in which GIS address-matching was I applied to a transportation problem at Oregon Health Sciences University (OHSU) in Portland, Oregon. The transportation problem at OHSU is common to major employment centers in urban …