Convert CADRG to 3TF

Understanding the CADRG and 3TF file formats

CADRG (Compressed ARC Digitized Raster Graphics) is a raster map format developed by the National Geospatial-Intelligence Agency (NGA) for military and aeronautical charting. It is widely used for digital mapping and navigation systems, offering compressed, georeferenced raster images.

3TF is a less common geospatial file format, often associated with 3D terrain files used in simulation and visualization applications. It typically stores terrain elevation data and texture information for rendering 3D landscapes.

Why convert CADRG to 3TF?

Converting CADRG to 3TF allows users to utilize military or aeronautical raster maps in 3D visualization platforms, simulation software, or virtual globe applications that require 3TF terrain files. This conversion is essential for integrating authoritative map data into immersive 3D environments.

How to convert CADRG to 3TF

Direct conversion from CADRG to 3TF is not natively supported by most GIS software. The process typically involves two steps:

1. Convert CADRG to a common raster format (such as GeoTIFF) using GIS tools.
2. Convert the raster file to 3TF using specialized 3D terrain generation software.

Recommended software for conversion

• Global Mapper: This powerful GIS tool can import CADRG files and export them to GeoTIFF or other raster formats. Use File → Export Raster/Image Format to save as GeoTIFF.
• Cesium ion: For converting GeoTIFF to 3TF (Cesium 3D Tiles format), upload your GeoTIFF to Cesium ion, which will process and output 3D terrain tiles in the 3TF format.
• QGIS: Open-source GIS software that can read CADRG (with plugins) and export to GeoTIFF. Use Project → Import/Export → Export Map to Image.

Step-by-step conversion process

1. Open your CADRG file in Global Mapper or QGIS.
2. Export the map as a GeoTIFF raster image.
3. Upload the GeoTIFF to Cesium ion or another 3D terrain generator that supports 3TF output.
4. Download the resulting 3TF file for use in your 3D visualization application.

Tips and considerations

• Ensure your CADRG files are properly georeferenced for accurate terrain placement.
• Check the compatibility of your 3D visualization software with the 3TF format.
• Some conversions may require additional metadata or projection adjustments.