Building a Better Basemap

by Anne Egger

Pilot, glaciologist, and lidar specialist Chris Larsen downloading data from the flight over the White Mountains. The GPS and lidar sensor units used can be seen at lower left. Image credit: Anne Egger
Pilot, glaciologist, and lidar specialist Chris Larsen downloading data from the flight over the White Mountains. The GPS and lidar sensor units used can be seen at lower left. Image credit: Anne Egger

Many colleges and universities use the (Cambrian) Poleta Folds of the White-Inyo range as a site for summer field mapping projects. This spectacular outcrop allows students to develop skills in geologic mapping because the stratigraphy is well defined, units are distinctive in color and character, and exposures are nearly continuous.

Despite the common use of this area, the basemaps with which students have long been working are hand-surveyed topographic maps and, while more detailed than published USGS quadrangle maps, do not portray accurately the topography at the scale needed. This frustrates students and instructors alike. The difficulty students face locating themselves on the map hampers their ability to achieve a deep understanding of the geology and structures, yet interpreting the folds and faults are the primary learning targets.

A coalition of universities who run field mapping projects in the Poleta Folds set out to solve this problem. The coalition, led by Anne Egger of Central Washington University, included Caltech, CSU-Sacramento, Oregon State University, UC Davis, UCLA, UC Santa Cruz, and Western Washington University. They worked with Chris Larsen of the University of Alaska-Fairbanks, who supplied the plane.

A spectacular view of the Poleta Folds area through the airplane window. Image credit: Anne Egger
A spectacular view of the Poleta Folds area through the airplane window. Image credit: Anne Egger

In mid-February, 2014, Chris and Anne flew over the Poleta area and collected high-resolution lidar and photogrammetry data. Once processed, the data will be made available on Open Topography, where they can be downloaded by anyone. Many of this summer’s geology students staying at White Mountain Research Center will be mapping on lidar basemaps rather than hand-drawn topographic maps.

Anne Egger is an assistant professor of geology and science education at Central Washington University.

Read more about the equipment setup used to produce the new Poleta Folds basemap.

This article originally appeared in the Spring 2014 issue of the White Mountain Research Center Newsletter.