Project: icepyx4gedi

Introduction

The Global Ecosystem Dynamics Investigation (GEDI) is a full waveform LiDAR instrument aboard the International Space Station developed by NASA specifically optimized for measuring forest structure at a global scale. The Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2) measures the height of a changing Earth via the ATLAS instrument which is optimized to measure changes in Earth's polar sea ice and land ice. However, ICESat-2 also collects elevation data over all surfaces from pole to pole. These data can be used together to map biophysical characteristics of ecosystems more completely and give scientists a better understanding of how these characteristics influence the global carbon cycle. By creating tools and utilities that access and work with both GEDI and ICESat-2 data using common routines, this work could lower barriers around working with these data together in activities like intercomparisons, fusion, and investigations that leverage synergies between the two sensors.

Collaborators

Name	Personal goals	Can help with	Role
Aaron Friesz @amfriesz	...	...	...
Jessica Scheick @JessicaS11	...	...	...
Scott Henderson @scottyhq	...	...	...
Jack Hayes @Jack-Hayes	...	...	...
Zachary Fair @zachghiaccio	...	...	...
Wei Ji Leong @weiji14	...	...	...
H Rainak Khan Real @hrkreal	...	...	...
Francesca Lingo @f-lingo	...	...	...
Chao Wang @ChaoEcohydroRS	...	...	...
Romina Piunno @RomiP	...	...	...
Mikala Beig @mikala-nsidc	...	...	...
Tasha Snow @tsnow3	...	...	...
Aimee Barciauskas @abarciauskas-bgse	...	...	...

The Problem

The file size, dataset nuances, and hierarchical file structure of GEDI and ICESat-2 data files make working with these data daunting and difficult. To work with both GEDI and ICESat-2 data one must develop separate workflows to access and work with these data.

Data & Tools

Data

We will focus on the footprint data products, not the gridded data products. The specific data products are listed below.

• GEDI L1B Geolocated Waveform Data Global Footprint Level (GEDI01_B v002)
• GEDI L2A Elevation and Height Metrics Data Global Footprint Level (GEDI02_A v002)
• GEDI L2B Canopy Cover and Vertical Profile Metrics Data Global Footprint Level (GEDI02_B v002)

Tools

• h5py - has historically been the library used to read GEDI footprint data into Python.
• icepyx - "shared library of resources - including existing resources, new code, tutorials, and use-cases/examples - that simplify the process of querying, obtaining, analyzing, and manipulating ICESat-2 and (via the QUEST module) relevant ancillary datasets to enable scientific discovery." The icepyx Developers. icepyx Computer software
• xarray
• Dask
• GitHub

Resources

Below are links to resources (i.e., tutorials, scripts, packages, and repos) that may be useful for context or for learning to work with GEDI footprint data.

• https://github.com/nasa/GEDI-Data-Resources/tree/main
• https://github.com/ornldaac/gedi_tutorials
• https://github.com/carlos-alberto-silva/rGEDI
• https://github.com/EduinHSERNA/pyGEDI
• https://github.com/icesat2py/icepyx/blob/gedi/doc/source/example_notebooks/GEDI_play.ipynb
• https://github.com/aestovall/GEDI_Workshop
• https://github.com/search?q=repo%3ASlideRuleEarth%2Fsliderule-python%20gedi%20&type=code

Project Goals & Tasks

Goals

This project aims to create and/or extend methods and routines in the icepyx Python library to support GEDI footprint data products.

Contributions

Work and contribution can be added to the forked icepyx repo in the ICESAT-2HackWeek org. If you are participants want to create a fork to their own GitHub space and check in contributions there, that is fine as well.

Tasks

Below are the list of features to be integrated into the icepyx Python library

• Search and discover GEDI footprint data from Earthdata Cloud
• Read GEDI footprint data into an xarray object
• Find concurrent/intersecting ICESat-2 and GEDI data files
• GEDI quality filtering methods
• GEDI footprint to grid conversion
• Methods that make static and interactive plots for (stretch goal)
• Method to reduce the vertical step size (L2b) (stretch goal)

Project Results

See issues, pull requests and the project board at:

• https://github.com/ICESAT-2HackWeek/icepyx/issues?q=is%3Aissue
• https://github.com/ICESAT-2HackWeek/icepyx/pulls?q=is%3Apr
• https://github.com/orgs/ICESAT-2HackWeek/projects/12/views/2

Summary points:

• Completed:
  • Determine spatial and temporal domain for development (#4)
  • Determine how to read-in GEDI L2b from Earthdata Cloud into at xarray dataset (#3)
  • Visualize GEDI L2b and ATL08 using lonboard (#7)
  • Determine how to discover variables from the Harmony API (#19)
• In progress (to be continued after hackweek and upstreamed into icepyx):
  • Read-in or translate GEDI L2B data to geoparquet (#2)
  • Search integration into icepyx (#5)
  • Data access integration into icepyx (#6)
  • Create a workflow for identifying coincident ICESat-2 x GEDI footprints in an input AOI (#1)
  • Modify icepyx Variables module to handle GEDI variable structure (#15)