Format Conversion Tools

Convert GDAL rasters to ISIS3, PDS, PLY, and other specialized formats

Format conversion utilities for transforming GDAL-supported rasters into specialized planetary science and 3D formats.

Overview

These tools enable conversion from standard geospatial formats (GeoTIFF, etc.) to specialized formats used in planetary science, 3D visualization, and archival systems.

ISIS3 Conversion

Astropedia_gdal2ISIS3.py

Creates ISIS3-compatible cube files (raw with ISIS3 label) from any GDAL-supported image.

infile · string · required

Path to input GDAL-supported raster

outfile · string · required

Path to output ISIS3 cube file (.cub)

-debug · flag · default: "false"

Print detailed image information during conversion

-noimage · flag · default: "false"

Generate only the .lbl label file without the image data

-attach · flag · default: "false"

Attach the label to the ISIS image (requires ISIS3 installation)

-force360 · flag · default: "false"

Force longitude system to 360-degree domain

-centerLon · float

Override the center longitude value

-base · float

Set the base offset for pixel values

-multiplier · float

Set the scaling multiplier for pixel values

Usage:

python Astropedia_gdal2ISIS3.py [options] infile output.cub

Examples:

Basic Conversion

python Astropedia_gdal2ISIS3.py mars_dem.tif mars_dem.cub

Currently works only for a limited set of images. Verify output for your specific use case.

LMMP_gdal2PDS.py

Simple brute-force script to convert from GDAL-supported formats to PDS3 images with labels.

Purpose: Generate PDS3-compliant image files for planetary data archiving.

Usage:

python LMMP_gdal2PDS.py infile outfile.img

PDS3 (Planetary Data System version 3) is a NASA standard for archiving and distributing planetary science data.

3D Mesh Conversion

gdal2PLY.py

Generate triangulated 3D mesh (PLY format) from digital elevation models (DEMs).

inputfile · string · required

Path to input DEM raster

outputfile · string · required

Path to output .ply mesh file

Usage:

python gdal2PLY.py inputfile.tif outputfile.ply

Example:

python gdal2PLY.py crater_dem_10m.tif crater_mesh.ply

How It Works

1. Read DEM elevation data

   Load the entire raster into a NumPy array

2. Create vertex array

   Generate 3D vertices (X, Y, Z) for each pixel using geotransformation

3. Build triangle index

   Create face indices connecting adjacent vertices in a triangulated mesh

4. Write PLY file

   Export vertices and faces in binary PLY format for efficient storage

NoData Handling

The script does not automatically handle NoData values. Use this workaround:

1. Find minimum elevation

   gdalinfo -mm input_DEM.tif
   

   Example output: Computed Min/Max=-2790.594, 1234.567

2. Set NoData to safe value

   Round down from minimum and optionally resample:

   gdalwarp -dstnodata -2791 -tr 10 10 -r bilinear \
     input_DEM.tif output_DEM_10m_nodata.tif
   
3. Convert to PLY

   python gdal2PLY.py output_DEM_10m_nodata.tif output_mesh.ply
   

PLY Format

The output PLY (Polygon File Format) is a widely-supported 3D mesh format:

• Binary format: Efficient storage (default)
• Contains: Vertex positions (X, Y, Z) and triangle face definitions
• Compatible with: MeshLab, Blender, CloudCompare, and many 3D viewers

Requirements

ISIS3 Scripts

pip install gdal
# Optional: ISIS3 for -attach flag

PLY Script

pip install gdal numpy
# Recommended: Anaconda distribution
conda install gdal numpy

Output File Structures

ISIS3 Cube (.cub)

ISIS3 cubes consist of:

Label Section

PVL (Parameter Value Language) metadata describing:

• Image dimensions and data type
• Projection and coordinate system
• Pixel scaling (base + multiplier)
• Processing history

Image Data

Raw binary raster data:

• Tile or band-sequential organization
• Native byte order
• Optional compression

PLY Mesh

ply
format binary_little_endian 1.0
element vertex 262144
property float x
property float y
property float z
element face 261121
property list int int vertex_index
end_header
[binary vertex data]
[binary face index data]

Use Cases

ISIS3 Processing

Ingest data into USGS ISIS3 for planetary image processing pipelines

PDS Archiving

Prepare datasets for submission to NASA’s Planetary Data System

3D Visualization

Create interactive 3D terrain meshes from elevation data

Data Sharing

Convert to formats compatible with legacy planetary software

Quality Assurance

Inspect DEMs in 3D mesh viewers for artifacts and anomalies

Web Publishing

Generate lightweight meshes for web-based 3D viewers

Credits

• ISIS3 scripts: Trent Hare, USGS ([e-mail])
• gdal2PLY.py: Based on work by Jake (GIS StackExchange), modified by Trent Hare
• Original gdalinfo.py authors: Even Rouault, Frank Warmerdam

These tools are provided as-is for planetary science workflows. Always validate output before use in production systems.