Unmanned aerial system data of Lirung Glacier and Langtang Glacier for 2013–2018

This dataset contains the raw data as well as produced image mosaics, digital elevation models (DEMs) and data derivatives of optical (RGB) unmanned aerial system (UAS) surveys of the debris-covered Lirung Glacier (9 surveys, 2013–2018) and Langtang Glacier (7 surveys, 2014–2018) in the Langtang Catchment, Nepalese Himalaya.

All data in this dataset are stored in tape archive (tar) or gzip-compressed tape archive (tar.gz) formats and require extraction before use.

The projected coordinate system used in this dataset is WGS 1984 UTM Zone 45N (EPSG:32645). Survey dates are always provided as yyyymmdd.

File descriptions

• dems_<glacier>.tar
  20 cm resolution DEMs that were derived from the raw UAS images. DEMs of all survey dates are included in the tar archives. File format is GeoTIFF.
   
• orthomosaics_<glacier>.tar
  10 cm resolution image mosaics of orthorectified source imagery (orthomosaics) that were derived from the raw UAS images. Orthomosaics of all survey dates are included in the tar archives. File format is GeoTIFF.
   
• point-clouds_<glacier>.tar.gz
  Dense point clouds that were derived from the raw UAS images. Point clouds of all survey dates are included in the tar archive. File format is ASPRS LAS. Note that additional gzip-compression has been applied to the archives.
   
• raw-data_<glacier>_<datestamp>.tar
  Raw data of each of the surveys that were performed over 2013–2018. The filename includes the glacier name and the survey date. Each tar archive contains directories for each UAS flight associated to that specific survey, indicated by f1, f2, ..., fn. The flight directories have the following contents:
  • img
    Subdirectory that contains the individual images in JPEG format captured by the UAS camera.
  • *flight_path.kml (not present for all surveys)
    Keyhole Markup Language file that contains the flight path of the UAS recorded by its internal GPS+GLONASS sensor.
  • *image_geoinfo.txt
    Table with coordinates (x,y,z) and UAS orientation (roll, tilt, yaw) for every image in img, which were recorded by the UAS' internal GPS+GLONASS sensor and gyroscope, respectively.
  • *drone_log.bbx or *drone_log.bb3
    Binary flight log file from the UAS containing detailed flight information. Can be read by the proprietary eMotion software by UAS manufacturer senseFly.
     
• supplementary-animation_<glacier>.gif
  Animations of Langtang Glacier (2014–2018) and Lirung Glacier (2013–2017) supplementary to Kraaijenbrink & Immerzeel (2020). The high resolution time lapse animations are constructed from composites of the orthomosaic and hillshaded DEM. Since the animations are in GIF format, they are best viewed in a web browser in which they can be zoomed and panned.
   
• supplementary-data-to-article.tar
  Data derivatives as presented in Kraaijenbrink & Immerzeel (2024). The tar archive contains a README file with additional information for each of the datasets present in the archive. The archive contains:
  • Three dimensional error measurements of the UAS-derived orthomosaics and elevation models
  • Vector outlines of the areas of interest of both glaciers
  • Surface displacement (i.e. velocity) between survey pairs (8 m resolution)
  • Uncorrected and flow-corrected DEMs (1 m resolution)
  • Elevation change (dh/dt) and surface mass balance (db/dt) grids based on pixel-wise regression (1 m resolution)
  • Point cloud extracts of supraglacial ice cliff cross profiles

Reference

For further information, e.g. about the UAS systems and cameras used, as well as detailed descriptions of the data and the applied data processing please refer to:

<Insert reference>

License

This dataset is licensed under Creative Commons Attribution 4.0 International (CC BY 4.0).
(https://creativecommons.org/licenses/by/4.0/)

Correspondence

Dr Philip Kraaijenbrink (p.d.a.kraaijenbrink@uu.nl)
Prof Dr Walter Immerzeel (w.w.immerzeel@uu.nl)