Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 13 of 13
Full-Text Articles in Life Sciences
Integrating Drone Technology With Gps Data Collection To Enhance Forestry Students Interactive Hands-On Field Experiences, Daniel Unger, I-Kuai Hung, Yanli Zhang, David Kulhavy
Integrating Drone Technology With Gps Data Collection To Enhance Forestry Students Interactive Hands-On Field Experiences, Daniel Unger, I-Kuai Hung, Yanli Zhang, David Kulhavy
Faculty Publications
Undergraduate students pursuing a Bachelor of Science in Forestry (BSF) at Stephen F. Austin State University (SFA) within the Arthur Temple College of Forestry and Agriculture (ATCOFA) attend an intensive 6-week hands-on instruction in applied field methods. The second week of field station is focused on land measurement activities to introduce students to practical, hands-on, and technology based ways to survey forest boundaries. On Monday of the second week students are introduced to the concepts of how to use a handheld compass to navigate from point to point, use a consumer-grade handheld Global Positioning System (GPS) unit for collecting the …
Accuracy Of Unmanned Aerial System (Drone) Height Measurements, Daniel Unger, I-Kuai Hung, David Kulhavy, Yanli Zhang, Kai Busch-Peterson
Accuracy Of Unmanned Aerial System (Drone) Height Measurements, Daniel Unger, I-Kuai Hung, David Kulhavy, Yanli Zhang, Kai Busch-Peterson
Faculty Publications
Vertical height estimates of earth surface features using an Unmanned Aerial System (UAS) are important in natural resource management quantitative assessments. An important research question concerns both the accuracy and precision of vertical height estimates acquired with a UAS and to determine if it is necessary to land a UAS between individual height measurements or if GPS derived height versus barometric pressure derived height while using a DJI Phantom 3 would affect height accuracy and precision. To examine this question, height along a telescopic height pole on the campus of Stephen F. Austin State University (SFASU) were estimated at 2, …
Comparing Remotely Sensed Pictometry® Web Based Slope Distance Estimates With In Situ Total Station And Tape Slope Distance Estimates, David Kulhavy, Daniel Unger, Yanli Zhang, Phillip Bedford, I-Kuai Hung
Comparing Remotely Sensed Pictometry® Web Based Slope Distance Estimates With In Situ Total Station And Tape Slope Distance Estimates, David Kulhavy, Daniel Unger, Yanli Zhang, Phillip Bedford, I-Kuai Hung
Faculty Publications
Slope distance was measured between the top of 30 light poles and their respective ground level coordinate identified within a central parking lot on the campus of Stephen F. Austin State University, Nacogdoches, Texas. Slope distance measured using Pictometry® hyperspatial 4-inch (10.2 centimeters) multispectral imagery within a web based interface was compared to in situ total station and tape measured slope distance. The range for mean slope distance for Pictometry®, total station, and tape measured slope distance was 0.05 meters. Mean slope distance was 15.36 meters, 15.37 meters, and 15.41 meters for Pictometry®, total station, …
Accuracy Assessment Of Pictometry® Height Measurements Stratified By Cardinal Direction And Image Magnification Factor, Daniel Unger, David Kulhavy, I-Kuai Hung, Yanli Zhang
Accuracy Assessment Of Pictometry® Height Measurements Stratified By Cardinal Direction And Image Magnification Factor, Daniel Unger, David Kulhavy, I-Kuai Hung, Yanli Zhang
Faculty Publications
The aim of this project was to ascertain if Pictometry® estimated height could be used in lieu of field-based height estimation. Height of a light pole measured with a telescopic height pole was compared to Pictometry® hyperspatial 4-inch (10.2 centimeters) multispectral imagery estimated light pole height on the campus of Stephen F. Austin State University, Nacogdoches, Texas. Average percent agreement between light pole height and Pictometry® estimated light pole height summarized by Pictometry® image magnification factors at 100%, 125%, 150%, 200%, and 300% magnification were within 98% of light pole height with percent disagreement ranging from …
Evaluating Interactive Transect Area Assessments Hands-On Instruction For Natural Resource Undergraduate Students, Daniel Unger, Sarah Schwab, Ryan Jacques, Yanli Zhang, I-Kuai Hung, David L. Kulhavy
Evaluating Interactive Transect Area Assessments Hands-On Instruction For Natural Resource Undergraduate Students, Daniel Unger, Sarah Schwab, Ryan Jacques, Yanli Zhang, I-Kuai Hung, David L. Kulhavy
Faculty Publications
Undergraduate students pursuing a Bachelor of Science in Spatial Science degree at Stephen F. Austin State University (SFASU) receive instruction in the spatial sciences with a focus on hands-on applications. All undergraduate students take the course Introduction to Spatial Science which includes a comprehensive overview of spatial science incorporating a comparison of standard inexpensive area assessment techniques with high-end computer based area assessment methodologies. Students within this course were instructed how to assess the area of a surface feature on an aerial image with a ruler applying the transect method. Student's average Root Mean Square Error (RMSE) between a student's …
Urban Tree Height Assessment Using Pictometry Hyperspatial 4-Inch Multispectral Imagery, Daniel Unger, David Kulhavy, Jeffrey M. Williams, David Creech, I-Kuai Hung
Urban Tree Height Assessment Using Pictometry Hyperspatial 4-Inch Multispectral Imagery, Daniel Unger, David Kulhavy, Jeffrey M. Williams, David Creech, I-Kuai Hung
Faculty Publications
Tree height is a critical variable of forest inventory assessments, and estimating the height of trees has been a component of forest inventory assessments for decades. The actual tree height of 60 open-grown baldcypress (Taxodium distichum) trees measured with a telescopic height pole were compared to Pictometry hyperspatial 4-in. multispectral imagery estimated tree height on the campus of Stephen F. Austin State University, Nacogdoches, Texas. Linear correlation coefficients (r) between actual tree height and Pictometry-estimated tree height for all 60 trees and the shortest 30 and tallest 30 trees were [1]0.997 for all r values. Pictometry estimated tree …
A Test Of The Mean Distance Method For Forest Regeneration Assessment, Daniel Unger, Jeremy P. Stovall, Brian P. Oswald, David Kulhavy, I-Kuai Hung
A Test Of The Mean Distance Method For Forest Regeneration Assessment, Daniel Unger, Jeremy P. Stovall, Brian P. Oswald, David Kulhavy, I-Kuai Hung
Faculty Publications
A new distance-based estimator for forest regeneration assessment, the mean distance method, was developed by combining ideas and techniques from the wandering quarter method, T-square sampling and the random pairs method. The performance of the mean distance method was compared to conventional 4.05 square meter plot sampling through simulation analysis on 405 square meter blocks of a field surveyed clumped distribution and a computer generated random distribution at different levels of density of 100, 50 and 25%. The mean distance method accurately estimated density on the random populations but the mean distance method estimates were more variable than those of …
Accuracy Assessment Of Land Cover Maps Of Forests Within An Urban And Rural Environment, Daniel Unger, I-Kuai Hung, David L. Kulhavy
Accuracy Assessment Of Land Cover Maps Of Forests Within An Urban And Rural Environment, Daniel Unger, I-Kuai Hung, David L. Kulhavy
Faculty Publications
Land cover maps of forests within an urban and rural environment derived from high spatial resolution multispectral data (QuickBird) and medium spatial resolution multispectral data (Landsat ETM+ and SPOJ 4) were compared to ascertain whether increased spatial resolution increases map accuracy of forests and whether map accuracy varies across land cover classification schemes. It is commonly assumed that increased spatial resolution would probably increase land cover map accuracy regardless of land cover classification methodology. This study assessed whether that assumption is correct within a rural and an urban environment. Map accuracy for modified National Land Cover Data (NLCD) 2001 Level …
Validating One-On-One Gps Instruction Methodology For Natural Resource Area Assessments Using Forestry Undergraduate Students, Daniel R. Unger
Validating One-On-One Gps Instruction Methodology For Natural Resource Area Assessments Using Forestry Undergraduate Students, Daniel R. Unger
Faculty Publications
Undergraduate students pursuing a Bachelor of Science in Forestry (BSF) at Stephen F. Austin State University (SFA) attend an intensive 6-week residential hands-on instruction in applied field methods. The intensive 6-week instruction includes learning how to use the Global Positioning System (GPS) with a Garmin eTrex HCx GPS unit to accurately calculate area. Students were instructed how to assess the accuracy of their GPS collected waypoints by calculating the Root Mean Square Error (RMSE) comparing their GPS collected area measurements with instructor on-screen digitized area. Student’s average area RMSE between digitized and GPS derived area was 0.015 hectares, whereas instructor’s …
Accuracy Evaluation Of Hand Held Gnss Units In Applied Urban Forestry (Abstract), Daniel Unger, Raymond Whitlock, Yanli Zhang, Jon Erhart, Randy Carmical
Accuracy Evaluation Of Hand Held Gnss Units In Applied Urban Forestry (Abstract), Daniel Unger, Raymond Whitlock, Yanli Zhang, Jon Erhart, Randy Carmical
Faculty Posters
No abstract provided.
Accuracy Assessment Of Perimeter And Area Calculations Using Consumer-Grade Gps Units In Southern Forests, Daniel Unger, I-Kuai Hung, Yanli Zhang, Jeffrey Parker, David Kulhavy, Dean W. Coble
Accuracy Assessment Of Perimeter And Area Calculations Using Consumer-Grade Gps Units In Southern Forests, Daniel Unger, I-Kuai Hung, Yanli Zhang, Jeffrey Parker, David Kulhavy, Dean W. Coble
Faculty Publications
Field foresters have long required a method of accurate measurement of perimeter and area during forest management activities. Perimeter and area assessments that can be derived from individual waypoints collected via global positioning system (GPS) units can be an expensive endeavor. A question of concern for practicing foresters is as the cost of GPS units increase does the accuracy of waypoints and any derived perimeter and area assessments also increase? This research evaluated whether the dynamic collection of waypoints using consumer-grade GPS units ranging from $50 to $700 provide a sufficient level of accuracy for the calculation of perimeter and …
Standardized, Cost-Effective, And Repeatable Remote Sensing Methodology To Quantify Forested Resources In Texas, Daniel Unger, James Kroll, I-Kuai Hung, Jeffrey M. Williams, Dean W. Coble
Standardized, Cost-Effective, And Repeatable Remote Sensing Methodology To Quantify Forested Resources In Texas, Daniel Unger, James Kroll, I-Kuai Hung, Jeffrey M. Williams, Dean W. Coble
Faculty Publications
A standardized remote sensing methodology was evaluated for its use in quantifying the forested resources of the state of Texas in a timely and cost-effective manner. Landsat data from 2002 were used to create a land cover base map encompassing a four-county study area in East Texas. Site-specific and non-site-specific accuracy assessments of the classified map indicate that overall the 2002 base map accuracy of 72.78% was within acceptable remote sensing standards for Landsat data and that forest cover types derived from 2002, 1987, and 1980 Landsat data were within 4.4, 0.5, and 7.4% agreement with Forest Inventory and Analysis …
Multi-Source Image Classification, Hillary Tribby, James Kroll, Daniel Unger, I-Kuai Hung, Hans Michael Williams
Multi-Source Image Classification, Hillary Tribby, James Kroll, Daniel Unger, I-Kuai Hung, Hans Michael Williams
Faculty Presentations
Since multi-source image classifications have the ability to exceed single source processes, such as traditional unsupervised classification methods, this paper will present the integration of four types of data: Lidar, elevation, multispectral and thermal. Using multi-source data and maximum likelihood classification methodology, as well as all possible permutations of data types, this paper will discuss ways to increase accuracy assessments of forested areas in east Texas and find the best combination of data sources.