Quality Filtering¶

The extraction process automatically applies quality filtering to remove low-quality GEDI shots. This ensures that your analysis uses reliable data. From my experience, however, the default filters may not be appropriate for all landcover types. Therefore, you also have the option to disable quality filtering and implement your own criteria.

Default Filtering¶

By default, shots are filtered based on the following conditions:

Filter	Condition	Description
Quality Flag	`quality_flag == 1`	Shot meets quality standards
Degrade Flag	`degrade_flag == 0`	Shot is not in a degraded state
Detected Modes	`num_detectedmodes > 0`	At least one mode was detected
Elevation Check	`abs(elev - elev_dem_tdx) < 100`	Elevation difference < 100 m from DEM

Beam Sensitivity

The quality_flag already includes filtering for beam sensitivity in the default range of 0.9 - 1.0, so no additional sensitivity filtering is needed if this is what you want.

Filter Statistics in Logs¶

During extraction, gedixr logs the number and percentage of shots that were filtered out if quality filtering is enabled. Example log entry:

INFO | GEDI02_B_2024130044637_O30619_04_T06857_02_004_01_V002.h5 | 
  00234/01567 (14.93%) shots were filtered due to poor quality

Output File Naming¶

The output filename indicates whether default quality filtering was applied by using a suffix after the product type:

YYYYMMDDHHMMSS_L2B_1.parquet - Quality filtering was enabled
YYYYMMDDHHMMSS_L2B_0.parquet - Quality filtering was disabled

Disabling Quality Filtering¶

You have the option to disable the default quality filtering during data extraction. In this case, all shots are included in the output. The quality_flag and degrade_flag columns are still included in the output in addition to other related columns (e.g., sensitivity), allowing you to apply custom filtering afterward.

CLIPython

gedixr extract /path/to/data --no-quality-filter

from gedixr.extract import extract_data

gdf, out_path = extract_data(
    directory="/path/to/data",
    gedi_product='L2B',
    apply_quality_filter=False
)

Custom Quality Filtering¶

After extracting data without quality filtering, you can apply your own criteria:

from gedixr.extract import extract_data

# Extract without default filtering
gdf, out_path = extract_data(
    directory="/path/to/data",
    gedi_product='L2B',
    apply_quality_filter=False
)

# Apply custom filters
gdf_flt = gdf[
    (gdf['quality_flag'] == 1) &
    (gdf['degrade_flag'] == 0) &
    (gdf['num_detectedmodes'] > 0) &
    (gdf['sensitivity'] > 0.95) & # Higher lower bound on beam sensitivity
    (abs(gdf['elev'] - gdf['elev_dem_tdx']) < 50)  # Stricter elevation check
]