DOI: 10.5281/zenodo.18343026
title: DGGS Benchmark Replication Study - Results Dataset

description: DGGS Benchmark Replication Study - Results Dataset

 

Description

This dataset contains the results of a reproducible replication study of the benchmarks presented in:



Law, R.M. & Ardo, J. (2024). "Using a discrete global grid system for a scalable, interoperable, and reproducible system of land-use mapping." Big Earth Data, 9(1), 29-46. DOI: 10.1080/20964471.2024.2429847


The replication validates the paper's two central claims:



Vector benchmark: DGGS provides "orders of magnitude" performance improvement over traditional vector overlay operations

Raster benchmark: DGGS and raster methods show "roughly equivalent performance" for classification tasks


Files Included




File
Description




vector_benchmark.csv
Timing results for vector overlay vs DGGS comparison


raster_benchmark.csv
Timing results for raster vs DGGS comparison


indexing_benchmark.json
Comparison of H3 loop vs xdggs vectorized indexing


system_info.json
Hardware/software environment details for reproducibility


summary.json
Structured summary of results and validation status


benchmark_unified.png
Visualization of all benchmark results (PNG format)


benchmark_unified.pdf
Visualization of all benchmark results (PDF format)




Benchmark Configuration

Vector Benchmark (Figure 6 replication)



Layers tested: 5, 10, 20, 50

H3 resolution: 14 (matching paper)

Method: Voronoi polygons with random point distribution, dissolved by binary value, then overlaid


Raster Benchmark (Figure 7 replication)



Layers tested: 10, 50, 100, 500, 1,000, 5,000, 10,000

H3 resolution: 9

Raster size: 100 × 100 pixels per layer

Method: Neutral Landscape Model (mid-point displacement) with Gaussian smoothing


Classification Logic

Following the paper's methodology, classification uses seven mathematical functions applied to summed layer values:



Prime number test

Perfect number test

Triangular number test

Square number test

Pentagonal number test

Hexagonal number test

Fibonacci number test


The combination of these seven binary outputs produces up to 127 distinct classes.

Key Results

Vector Benchmark




Layers
DGGS Time (s)
Vector Time (s)
DGGS Speedup




5
~0.02
~0.4
22×


10
~0.03
~2.5
105×


20
~0.05
~27
541×


50
~0.13
~780
5,999×




Conclusion: DGGS is orders of magnitude faster than vector overlay. The speedup increases with layer count because vector overlay creates exponentially more sliver polygons, while DGGS cell count remains fixed.

Raster Benchmark



DGGS pre-indexed vs Raster classification: Roughly equivalent performance (within 2-3×)

xdggs vectorized indexing: Significantly faster than H3 loop-based indexing for coordinate-to-cell conversion


Conclusion: For pre-indexed data, DGGS classification performance matches raster, validating the paper's claim.

Understanding the Raster Benchmark Plot

The raster benchmark plot shows four methods:




Line
Method
What it measures




🟠 Raster (baseline)
NumPy array operations
Traditional raster stacking and classification


🟦 DGGS+H3 (reproduction)
H3 loop indexing
Paper's original approach: index each layer with H3, then classify


🟣 DGGS+xdggs (replication)
xdggs vectorized indexing
Alternative approach: index with xdggs, then classify


🟢 DGGS pre-indexed
Read from Parquet
Paper's target scenario: data already indexed to DGGS




Key interpretation:



The DGGS pre-indexed line (green) represents the paper's main use case: data is indexed to DGGS once, then queried many times

The Classification Only subplot (bottom-right) isolates this comparison, showing DGGS and raster are roughly equivalent

The gap between DGGS+H3 and DGGS+xdggs demonstrates the indexing speedup from vectorization


Methodology

What is a DGGS?

A Discrete Global Grid System (DGGS) is a spatial reference system that partitions the Earth's surface into a hierarchical sequence of equal-area cells. Unlike traditional coordinate systems, DGGS provides:



Fixed discretization: Space is divided into a finite number of cells at each resolution level

Hierarchical structure: Cells nest within parent cells, enabling multi-resolution analysis

Unique cell identifiers: Each cell has a unique ID that implicitly encodes its location


This study uses H3, Uber's hexagonal hierarchical spatial index, which tessellates the globe with hexagonal cells (and 12 pentagons). H3 has 16 resolution levels, from ~4 million km² (resolution 0) to ~0.9 m² (resolution 15) per cell.

Key insight: When data is indexed to a DGGS, spatial joins become simple attribute joins on cell IDs, avoiding expensive geometric intersection computations.

Reproduction vs Replication

Following established terminology in reproducibility research:




Term
Definition
Implementation in this study




Reproduction
Same methodology, same tools
H3 library + Polars (matching the paper's approach)


Replication
Same methodology, alternative tools
xdggs for vectorized H3 indexing




The Role of xdggs in Replication

xdggs is a Python library that provides Xarray extensions for DGGS operations. It offers an alternative implementation for converting geographic coordinates to DGGS cell IDs.

Why xdggs matters for this replication:

The paper's workflow has two main phases:



Indexing phase: Convert raster pixels or vector geometries to H3 cell IDs

Classification phase: Query the indexed data to assign land-use classes


The original paper used the H3 Python library, which requires looping through each coordinate to convert it to a cell ID:

# H3 loop-based indexing (paper's approach)
cell_ids = [h3.latlng_to_cell(lat, lng, resolution) 
            for lat, lng in coordinates]  # Slow: one call per pixel


xdggs provides vectorized operations that convert all coordinates in a single call:

# xdggs vectorized indexing (replication approach)
cell_ids = h3_info.geographic2cell_ids(lngs, lats)  # Fast: one call for all pixels


Performance comparison (from this replication):




Method
Time per layer
Relative speed




H3 loop
~0.15s
1× (baseline)


xdggs vectorized
~0.001s
~150× faster




This demonstrates that while the paper's methodology is sound, alternative tools can significantly improve the indexing phase performance without changing the scientific conclusions.

Implications for the Paper's Claims

The replication with xdggs validates the paper's conclusions:



Vector benchmark: The speedup comes from replacing geometric intersection with cell ID joins—this is independent of the indexing method used

Raster benchmark: Pre-indexed DGGS data performs equivalently to raster regardless of how the indexing was done


The xdggs results show that the DGGS approach can be even more efficient with optimized tooling, strengthening the paper's argument for DGGS adoption.

Software Environment



Python 3.11

H3 v4.x (Uber's hexagonal hierarchical spatial index)

xdggs (vectorized DGGS operations)

GeoPandas, Rasterio, NumPy, Pandas, Polars

SciPy (Voronoi tessellation, Gaussian filtering)


How to Reproduce

The complete replication environment is available at: GitHub: https://github.com/annefou/dggs-benchmark-replication

Using Docker (Recommended)

docker pull ghcr.io/annefou/dggs_replication_2026:latest
docker run -v $(pwd)/results:/app/results ghcr.io/annefou/dggs_replication_2026:latest


Using Python

git clone https://github.com/annefou/dggs-benchmark-replication.git
cd dggs-benchmark-replication
pip install -r requirements.txt
python run_replication.py --all


Citation

If you use this dataset, please cite both the original paper and this replication:

Original Paper

@article{law2024dggs,
  title={Using a discrete global grid system for a scalable, interoperable, 
         and reproducible system of land-use mapping},
  author={Law, Richard M. and Ardo, James},
  journal={Big Earth Data},
  volume={9},
  number={1},
  pages={29--46},
  year={2024},
  publisher={Taylor \& Francis},
  doi={10.1080/20964471.2024.2429847}
}


This Replication Dataset

@dataset{fouilloux2026dggs_replication,
  author       = {Fouilloux, Anne},
  title        = {{DGGS Benchmark Replication Study: Results Dataset}},
  year         = {2026},
  publisher    = {Zenodo},
  doi          = {10.5281/zenodo.XXXXXXX},
  url          = {https://doi.org/10.5281/zenodo.XXXXXXX}
}


Original Benchmark Code

The original benchmark code from the paper is available at:



Repository: https://github.com/manaakiwhenua/dggsBenchmarks

Version used: v1.1.1


License

This dataset is released under the MIT License.

Author

Anne FouillouxORCID: 0000-0002-1784-2920Affiliation:  LifeWatch ERIC

Acknowledgments



Richard M. Law and James Ardo (Manaaki Whenua – Landcare Research) for the original research

Uber Technologies for the H3 library

The xdggs development team for vectorized DGGS operations


Related Resources

DGGS and H3



H3 Documentation: https://h3geo.org/

H3 Python API: https://uber.github.io/h3-py/

H3 Resolution Table: https://h3geo.org/docs/core-library/restable/

OGC DGGS Standard: https://www.ogc.org/standard/dggs/


xdggs and Related Tools



xdggs Documentation: https://xdggs.readthedocs.io/

xdggs GitHub: https://github.com/xarray-contrib/xdggs

h3ronpy (used by xdggs): https://github.com/nmandery/h3ronpy


Original Research



Original paper: https://doi.org/10.1080/20964471.2024.2429847

Original benchmark code: https://github.com/manaakiwhenua/dggsBenchmarks

vector2dggs tool: https://github.com/manaakiwhenua/vector2dggs

raster2dggs tool: https://github.com/manaakiwhenua/raster2dggs


Reproducibility Resources



FORRT Replication Handbook: https://forrt.org/replication_handbook/

The Turing Way - Reproducibility: https://the-turing-way.netlify.app/reproducible-research/


Dataset generated: January 2026Replication framework version: 2.0.0