Multi-Temporal Topographic Analysis of Natural Hazards Using OpenTopography

Location: S228 (Sievers Room). Sustainability, Energy and Environment Community (SEEC) Building, CU East Campus, Boulder, CO.

Instructors:
Cassandra Brigham & Chelsea Scott, Arizona State University
Christopher Crosby & Matt Beckley, EarthScope Consortium

Course Description:

The growing availability of multi-temporal, high-resolution topography datasets from lidar and photogrammetry offers new opportunities to quantify surface change driven by hazard-relevant processes — including earthquakes, volcanic eruptions, landslides, debris flows, coastal erosion, post-wildfire landscape response, and flood-driven channel change.

This short course introduces OpenTopography, an NSF-supported platform that streamlines the discovery, processing, visualization, and analysis of high-resolution topographic data. After a refresher on lidar, structure-from-motion photogrammetry, point clouds, and topographic differencing fundamentals, participants will explore OpenTopography's on-demand tools for computing vertical differences between overlapping pre- and post-event datasets. We will also cover how to interpret change results and quantify their uncertainty.

Through hands-on hazard case studies, attendees will gain practical experience processing multi-temporal datasets to quantify landscape change and correctly interpret differencing results. Participants will have the opportunity to apply differencing to their site of interest and ask instructors questions. This workshop is ideal for graduate students, hazards researchers, practitioners, and educators seeking to leverage freely available, high-resolution topographic data for hazard assessment and response.

Pre-course Preparations:

We will run this short course with the OpenTopography web-based interface and the Google Colaboratory web-based interface. To prepare for the course please complete the following tasks in advance of the course:

1. Ensure you have a Gmail account and at least 500 MB of Google Drive space
2. Create an OpenTopography account (if you do not already have one) at https://opentopography.org
3. Bring a laptop capable of connecting to the conference WiFi network, ideally with a webGL enabled browser like Chrome or Firefox
4. Watch Intro to OT webinar (1 hr): Introduction to OpenTopography
5. Watch point cloud webinar (1 hr): Introduction to Point Clouds
6. Watch digital elevation model webinar (1 hr): Introduction to Digital Elevation Models
7. Read Geosphere paper (2 hrs): Measuring change at Earth’s surface: On-demand vertical and three-dimensional topographic differencing implemented in OpenTopography

Tentative Agenda:

9:00: Welcome & intros (Crosby)

9:25: Data access review (Crosby)

10:05: Intro to topographic differencing (Scott)

10:50: Break

11:05: OT differencing tools & activity (Brigham)

12:30: Lunch

1:30: Error analysis & interpreting change (Brigham)

2:45: Break

3:00: Colab exercise: uncertainty on real disasters (Brigham)

4:40: Wrap-up

5:00: Short Course End

Other Resources:

• OpenTopography's resources on differencing
• Topographic Differencing Showcase
• Interpreting Errors in Topographic Differencing Results
• OpenTopography Video Tutorials
• Publication about OpenTopography's on-demand vertical and 3D differencing
• Publication about statewide lidar differencing of Indiana