Department of Geography

College of Liberal Arts

California State University, Long Beach

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Abstracts of Conference Presentations

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Dr. Suzanne P. Wechsler

will be the presenting co-author of a G-DEP assessment project

"Enhancing diversity in the geosciences." California Geographical Society meeting in Yosemite, April 2005.

This presentation will review an innovative interdisciplinary project at California State University, Long Beach that was designed to increase the attractiveness of the geosciences (physical geography, geology and archaeology) to underrepresented groups. The goal was to raise awareness of the geosciences by providing summer research opportunities to underrepresented high school and community college students and their faculty. Program results indicate that students are generally not aware of the potential of geosciences as a major and a career path. This unprecedented level of collaboration has set the groundwork for an institutional shift in inclusion of minorities in the geosciences.

Dr. Wechsler was the presenting author of a G-DEP field project team (Dr. Wechsler, Dr. Yuet Ling O'Connor (Pasadena City College), Peter Wohlgemuth (USDA Forest Service), Brian Sims, and Aziz Bakkoury:

"Centroid Hunting: The Truth Is out There -- or Is It?" to the Association of American Geographers meeting in New Orleans, March 2003.

Geographic Information Systems (GISs) are frequently used in assessment of natural resources. Digital Elevation Models are a common GIS data source for terrain representation and analysis. Slope and aspect are topographic parameters frequently derived directly from DEMs. Numerous algorithms exist to compute slope and aspect from an elevation grid (Burrough and McDonnell, 1998; Carter, 1992; 1990, Horn, 1981, and Zevenbergen and Thorne, 1987). This research evaluated and quantified the accuracy of the computer representation of elevation and derived topographic parameters (slope and aspect) by GISs. High accuracy Global Positioning Systems (GPS) were used to ground truth elevation as represented in a 10m resolution USGS DEM. Centroids of the 10m grid cells from the Glendora, CA 7.5-minute Level 2 USGS DEM were used as ground truth locations. Issues associated with the navigation to and location of centroid points, subgrid variability and GPS accuracy will be presented. Field measurements of elevation, slope and aspect collected in the Bell 1 research watershed located in the San Dimas Experimental Forest (SDEF) were compared with GIS-derived values. The accuracy of the computer's representation of elevation, slope and aspect is a function of (a) DEM grid resolution, (b) topographic complexity, and (c) the algorithms utilized by the GIS to compute slope and aspect.

Dr. Wechsler is the ninth co-author for the G-DEP team (Drs. Elizabeth L. Ambos, James C. Sample, Richard J. Behl, Robert D. Francis [Geological Sciences], Daniel O. Larson [Anthropology], María Teresa Ramírez-Herrera [Geological Sciences], Christine M. Rodrigue, Suzanne P. Wechsler [Geography], and David J. Whitney [Psychology]), presenting:

"GDEP (Geoscience Diversity Enhancement Program): Creating a Community-Based Summer Geoscience Research Program " to the Geological Society of America, in Denver during October 2002.

The Geoscience Diversity Enhancement Program (GDEP), initiated in fall 1999, is a 3-year NSF-funded effort to increase the diversity of undergraduates studying geoscience disciplines in the greater Long Beach area. California State University, Long Beach (CSULB) defines geosciences as studies in the geologic, physical geographic, archeologic and environmental science disciplines. GDEP represents a collaboration among four CSULB departments (geological sciences, geography, anthropology, and psychology), five community colleges, and the Long Beach Unified School District This comprehensive program is designed to foster geoscience research, strengthen exposure to the geosciences in secondary schools and community colleges, and graduate an increasing number of students from underrepresented groups who major in the geosciences. The cornerstone of the project is an intensive summer research experience. This year, four high school faculty, five community college faculty, nine CSULB faculty, eight undergraduates, and eight graduate students are working together on a variety of projects. The GDEP website includes abundant information about the projects (http://www.csulb.edu/geography/gdep). Some of the initial achievements of this project include: 1) assembling a community of interested geoscience researchers by outreach to non- CSULB campuses; 2) collection of pre-program data on student attitudes toward geoscience education and careers; 3) design and implementation of summer research programs to mentor potential geoscience majors; and 4) educating new students in research-related skills through on-campus workshops and training seminars. We will present results from our first summer of research activities and a preliminary analysis of how GDEP participation has affected student attitudes toward the geosciences.

Dr. Wechsler was the presenting author for the G-DEP team (Drs. Elizabeth L. Ambos [Geological Sciences], Christine M. Rodrigue, Suzanne P. Wechsler [Geography], Robert D. Francis, James C. Sample, Richard Behl, María Teresa Ramírez-Herrera [Geological Sciences], Daniel O. Larson [Anthropology], David J. Whitney [Psychology], Crisanne Hazen [Science Education]), presenting:

"GDEP (Geoscience Diversity Enhancement Program): An Interdisciplinary Summer Research Program to Increase the Diversity of Geography, Geology, and Archaeology Majors <http://www.csulb.edu/geography/gdep/>" to the Association of Pacific Coast Geographers, in San Bernardino during October 2002.

The Geoscience Diversity Enhancement Program (GDEP) is a 3-year NSF-funded effort to increase the diversity of undergraduates studying geoscience disciplines in the greater Long Beach area. California State University, Long Beach, defines geosciences as geology, physical geography, archaeology, and environmental science. GDEP represents a collaboration among 4 CSULB geoscience departments (Geological Sciences, Geography, and Anthropology), with assessment and outreach involving 2 other departments (Psychology and Science Education). The cornerstone of the project is an intensive summer research experience. This summer, the geoscience co-PIs are working with 5 faculty from 5 community colleges and 4 high-school faculty from the Long Beach Unified School District, 8 community college students, and 8 CSULB graduate student mentors on a variety of projects. Initial achievements of GDEP include: 1) assembling a community of collaborating geoscience researchers by outreach to non-CSULB campuses; 2) collection of pre-program data on student attitudes toward geoscience education and careers; 3) design and implementation of summer research programs to mentor potential geoscience majors; and 4) educating new students in research-related skills through workshops and training seminars. We will present results from our first summer of research activities and a preliminary analysis of how GDEP participation has affected student attitudes toward the geosciences.

Dr. Wechsler was also the second co-author of a related paper by the G-DEP team (David J. Whitney [Psychology], Suzanne P. Wechsler, Christine M. Rodrigue [Geography], María Teresa Ramírez-Herrera, Richard Behl, Elizabeth L. Ambos, Robert D. Francis, James C. Sample [Geological Sciences], Daniel O. Larson [Anthropology], and Crisanne Hazen [Science Education]:

"General Education Student Perceptions of the Geosciences," also at the Association of Pacific Coast Geographers, in San Bernardino during October 2002.

Eight faculty in the departments of geography, geology, and anthropology at California State University, Long Beach, received an NSF Geoscience Diversity Enhancement Project grant for 2001-04. This project aims to increase the number of underrepresented minority and disabled students majoring in the geosciences by involving local community college and, eventually, high school students and their nominating faculty in research collaborations with the CSULB co-PIs. Assessment of GDEP's success in altering student perceptions of the geosciences is central to the project. The project's assessment specialist and co-PIs surveyed introductory classes in the three departments at the beginning and end of the Spring 2002 semester as a baseline study for measuring the eventual impact of GDEP. This paper reports on the results of the pre-test surveys, comparing CSULB student perceptions of geography, geology, and geoarchaeology with one another at the beginning of the semester. It also reports on the results of the post-test, to assess the changes in these perceptions induced by the classroom experience, again comparing the three geosciences.

Dr. Wechsler also presented:

"Effect of Interpolation Method and Grid Cell Resolution on DEM Accuracy" to the Association of American Geographers meeting in Los Angeles in March 2002.

Researchers often interpolate their own digital elevation models (DEMs) for areas not covered by existing DEMs or in situations where the DEM must be of higher accuracy or more detailed resolution than existing data. The quality of a self-generated DEM is inextricably linked to both the interpolation method and the grid cell size selected for interpolation. It is necessary to recognize the combined influence of both these factors on the resulting DEM. This study investigated the accuracy of DEMs interpolated onto various sized grids from irregular spaced points. Inverse distance weighting (IDW), spline and kriging interpolation techniques were evaluated. Over 4000 elevation points were digitized from the Otisco Valley, NY USGS 7.5-minute quadrangle. Sample validation points were randomly extracted and DEMs interpolated from the remaining points. Accuracy was measured using the root mean square error, mean absolute difference and standard deviation of the difference computed from validation points. Different interpolation procedures generate different surfaces from the same data. Some algorithms perform better on smoother surfaces whereas others better represent rapidly varying topography. The grid cell resolution selected is of particular importance in the latter situation. The 10-m resolution DEM was less accurate than the 30-m for kriged and IDW surfaces. The spline method produced the most accurate DEM for this data. This analysis highlights the need for caution when deriving data from interpolated DEMs. An optimal interpolator is not recommended; that choice is site and use dependent and could be based on the results of an analysis utilizing this approach.

Dr. Wechsler made a panel presentation to the:

"GIS Articulation" panel at the Cal GIS conference, Sacramento, 2002.

Dr. Wechsler and graduate student Ms. Erin Stockenberg, presented:

"Environmental and Natural Resource Applications of GIS: Course Development," to the International Conference on GIS Education, CSU San Bernardino, 21-23 June 2001.

This presentation will describe the initiation and development of a course on environmental and natural resource applications of Geographic Information Systems (GIS). The objectives of the course, methodology and procedures used in the development of course materials, and skills acquired through the assignments will be presented. The methodology utilized could be applied to the development of other GIS application courses. This presentation will benefit both faculty and students interested in expanding GIS course offerings and developing GIS laboratory materials that enhance skills and utilize relevant data.

Dr. Wechsler also was an invited speaker at the Cal Poly Pomona GIS Expo, on May 10th. Her talk was entitled:

"GIS and Remote Sensing at California State University Long Beach: By Example."

Additionally, she presented:

"Effect of Digital Elevation Model Uncertainty and Scale on Topographic Parameter Estimators" to the Association of American Geographers meeting in New York City in late February and early March.

Digital Elevation Models (DEMs) are representations of topography with inherent errors that constitute uncertainty. DEM data are often used in analyses without quantifying the effects of these errors. DEMs are a commonly utilized standard data source for GIS based studies aimed at evaluating natural processes. Random errors in a DEM constitute uncertainty. The grid structure of a DEM imposes a scale on elevation and derived parameters. The effect of DEM scale was investigated in the context of DEM uncertainty in elevation and hydrologic parameters frequently derived from DEMs (slope, upslope contributing area and the topographic index). Uncertainty in two DEMs with different grid cell resolution (30m and 10m) corresponding to a portion of the Claryville, NY quadrangle was simulated using Monte Carlo techniques. Error was represented in two ways (a) by completely random fields and (b) by random fields that incorporated spatial autocorrelation specific to the DEM. Uncertainty was quantified in the context of the probability of meeting predetermined threshold values for the parameters and estimated via the root mean square error of simulated parameters. Results indicate that the higher resolution DEM, generally perceived as more precise, yields greater uncertainty in derived hydrologic parameters. The methodology applied can be used to quantify uncertainty due to random error in any DEM.

Dr. Wechsler also gave a paper entitled:

"Applications of a Methodology For Digital Elevation Model Uncertainty Simulation Within ArcView Spatial Analyst," to the GIScience 2000 meeting in Savannah, Georgia, in late October 2000.

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Last revised: 10/16/02
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