CADRG (Compressed ARC Digitized Raster Graphics) Reader/Writer

Licensing options for this format begin with FME Professional Edition.

FME can read and write data in the CADRG (Compressed ARC Digitized Raster Graphics) format.

Overview

CADRG is a general-purpose product, comprising computer-readable digital map and chart images. It supports various weapons, C3I theater battle management, mission planning, and digital moving map systems. CADRG data is derived directly from ADRG and other digital sources through downsampling, filtering, compression, and reformatting to the Raster Product Format (RPF) Standard.

CADRG files are usually physically formatted within a National Imagery Transmission Format (NITF) message. The CADRG Reader can read CADRG files with or without the NITF message wrapper. The CADRG Writer can create CADRG datasets with or without the NITF message wrapper. These options available in the Writer Feature Type Parameters.

The CADRG reader and writer implement the following standards:

  • MIL-C-89038
  • MIL-STD-2411
  • MIL-STD-2411-1
  • MIL-STD-2411-2

CADRG image data is of appropriate size and quality for use in military command and control systems, ground-based force to unit-level mission planning systems, and aircraft cockpit “moving map” displays. The post-reduction filtering scheme emphasizes legibility of text and contour lines to ensure that displayed and printed digital maps are readable and distinct. CADRG is intended to satisfy the needs of a broad range of users in its compression ratio, display and print quality and displayed screen size.

The CADRG datasets shall conform to MIL-STD-2411. It normally will be produced directly from source maps of all scales by processing and re-formatting into a CADRG frame file structure. Miscellaneous scale maps and charts or non-DMA maps may be the source for CADRG production. The processing includes spatial reduction (pixel downsampling) with filtering, vector quantization image compression, and color quantization.

To permit direct use by aircraft cockpit displays, CADRG data is arranged in frames and subframes with constant pixel sizes, and overlaps that are consistent with limited memory and processing capabilities of avionics computers.

FME considers a single CADRG TOC file to be a dataset.

The CADRG TOC file contains the location and name of the frame files. The frame files are raster files containing pixel data.