PDS4 Conversion Tools

Convert ISIS3 cubes to PDS4 format using GDAL with automated metadata extraction

Overview

These Python scripts demonstrate conversion from ISIS3 cubes to PDS4 format using GDAL’s PDS4 driver. They read ISIS3 label metadata and generate configuration files for gdal_translate, enabling automated conversions with proper PDS4 metadata.

PDS4 (Planetary Data System version 4) is NASA’s current standard for archiving planetary science data. These tools bridge ISIS3 and PDS4 workflows.

Available Scripts

isis3_to_pds4_LOLA_pvl.py

Uses the PVL library to parse ISIS3 labels.

isis3_to_pds4_LOLA_pysis.py

Uses the pysis library to read ISIS3 labels via ISIS commands.

Both scripts produce identical output but use different methods for reading ISIS3 metadata. Choose based on your environment and installed dependencies.

Installation

Requirements

For pvl version:

conda install -c conda-forge gdal
pip install pvl

For pysis version:

conda install -c conda-forge gdal
pip install pysis

GDAL 2.2.0 or later is required for PDS4 driver support. Use recent GDAL builds for best results.

Usage

isis3_to_pds4_LOLA_pvl.py

python isis3_to_pds4_LOLA_pvl.py input.cub output.config

Parameters

input.cub · string · required

Input ISIS3 cube file.

output.config · string · required

Output configuration file for gdal_translate.

-run · flag

Automatically execute gdal_translate after generating config.

-template · string

Path to custom PDS4 XML template. Defaults to $GDALDATA/pds4_template.xml.

Example Workflow

1. Generate Configuration

   Create a config file from your ISIS3 cube:

   python isis3_to_pds4_LOLA_pvl.py ldem_4.cub ldem_4.config
   

   Output:

   writing ldem_4.config
   No ObservationId in ISIS3 Label
   No FileName in ISIS3 Label
   
   Recommended gdal run:
   gdal_translate -of PDS4 -co IMAGE_FORMAT=GEOTIFF -co TEMPLATE=pds4_template.xml \
     --optfile ldem_4.config ldem_4.cub ldem_4_pds4.xml
   
2. Review Configuration

   Examine the generated config file:

   cat ldem_4.config
   

   Example output:

   #run as isis3_to_pds4_LOLA_pvl.py ldem_4.cub ldem_4.config
   -co VAR_TARGET_TYPE=Satellite
   -co VAR_INVESTIGATION_AREA_LID_REFERENCE="urn:nasa:pds:context:instrument_host:spacecraft.lro"
   -co VAR_TARGET=MOON
   -co VAR_INVESTIGATION_AREA_NAME="LUNAR RECONNAISSANCE ORBITER"
   -co VAR_LOGICAL_IDENTIFIER=LRO-L-LOLA-4-GDR-V1.0
   -co VAR_OBSERVING_SYSTEM_NAME=LOLA
   -co VAR_TITLE=LDEM_4
   
3. Execute Conversion

   Run the recommended gdal_translate command:

   gdal_translate -of PDS4 -co IMAGE_FORMAT=GEOTIFF \
     -co TEMPLATE=pds4_template.xml \
     --optfile ldem_4.config \
     ldem_4.cub ldem_4_pds4.xml
   

Automated Conversion

Use the -run flag to execute conversion automatically:

python isis3_to_pds4_LOLA_pvl.py -run ldem_4.cub ldem_4.config

Custom Template

Provide a custom PDS4 XML template:

python isis3_to_pds4_LOLA_pvl.py -template my_template.xml input.cub output.config

PDS4 Template Variables

The scripts extract ISIS3 metadata and map it to PDS4 template variables:

Variable	ISIS3 Source	Description
VAR_TARGET	Mapping/TargetName	Target body name (e.g., MOON, MARS)
VAR_TARGET_TYPE	Hardcoded	Set to “Satellite”
VAR_INVESTIGATION_AREA_NAME	Archive/InstrumentHostName	Mission name (e.g., “LUNAR RECONNAISSANCE ORBITER”)
VAR_LOGICAL_IDENTIFIER	Archive/DataSetId	Dataset identifier (e.g., “LRO-L-LOLA-4-GDR-V1.0”)
VAR_OBSERVING_SYSTEM_NAME	Archive/InstrumentId	Instrument name (e.g., “LOLA”)
VAR_TITLE	Archive/ProductId	Product title
VAR_INVESTIGATION_AREA_LID_REFERENCE	Hardcoded	Context URN for mission

Missing Metadata: If ISIS3 labels lack required fields, warnings are printed and those variables are omitted from the config file. You may need to manually add them.

PDS4 Format Details

What is PDS4?

PDS4 is the fourth major version of NASA’s Planetary Data System standard, featuring:

• XML Labels: Structured, validated metadata in XML format
• Multiple Data Formats: Supports FITS, GeoTIFF, raw binary, and more
• Context Products: Links to missions, instruments, targets, and investigators
• Schema Validation: Ensures compliance with PDS4 standards

GDAL PDS4 Driver

The GDAL PDS4 driver supports:

• Reading and writing PDS4 products
• GeoTIFF-embedded image data (IMAGE_FORMAT=GEOTIFF)
• Custom XML templates with variable substitution
• Spatial reference system preservation

For complete GDAL PDS4 driver documentation, see: http://www.gdal.org/frmt_pds4.html

Test Data

Example test data included in the repository:

~/workspace/source/PDS4gdal/test/ldem_4.cub
~/workspace/source/PDS4gdal/test/ldem_4_original_pds3.lbl

Data Source: LOLA 4 ppd DEM converted to ISIS3 from PDS: http://pds-geosciences.wustl.edu/missions/lro/lola.htm

Configuration File Format

The generated .config files contain gdal_translate options:

# Comment line with generation command
-co VAR_NAME=VALUE
-co VAR_NAME="VALUE WITH SPACES"

Use with gdal_translate --optfile config.txt to avoid lengthy command lines.

Customization

Modifying Extracted Metadata

Edit the Python scripts to extract additional ISIS3 metadata:

# Example: Add custom field
try:
    customField = isis3lbl['IsisCube']['MyGroup']['MyKeyword']
    theLine = '-co VAR_CUSTOM={}'.format(customField)
    fileConfig.write(theLine)
except KeyError:
    print('No MyKeyword in ISIS3 Label')

Custom PDS4 Templates

Create custom XML templates with placeholder variables:

<Mission_Area>
  <mission_name>${VAR_INVESTIGATION_AREA_NAME}</mission_name>
  <spacecraft_name>${VAR_SPACECRAFT_NAME}</spacecraft_name>
</Mission_Area>

The GDAL driver replaces ${VAR_*} with values from -co options.

Script Locations

~/workspace/source/PDS4gdal/isis3_to_pds4_LOLA_pvl.py
~/workspace/source/PDS4gdal/isis3_to_pds4_LOLA_pysis.py
~/workspace/source/PDS4gdal/pds4_template.xml

Troubleshooting

GDAL Version Issues

python -c "import gdal; print(gdal.__version__)"

Ensure GDAL >= 2.2.0 for PDS4 support.

Missing ISIS3 Metadata

If required fields are missing from ISIS3 labels, edit the config file manually:

-co VAR_LOGICAL_IDENTIFIER=YOUR-DATASET-ID

Template Not Found

Set GDAL_DATA environment variable:

export GDAL_DATA=/path/to/gdal/data

Or specify template explicitly:

-template /full/path/to/pds4_template.xml

Related Resources

• GDAL PDS4 Driver Documentation
• PDS4 Standards
• ISIS3 Documentation
• PVL Library
• pysis Library

These scripts serve as examples. Adapt them for your specific mission data and PDS4 requirements.