ECW (file format)

ECW (Enhanced Compression Wavelet) is a proprietary wavelet compression image format optimized for aerial and satellite imagery. It was developed by Earth Resource Mapping, and is now owned by Leica Geosystems. The lossy compression format efficiently compresses very large images with fine alternating contrast.

Properties
It has the following properties:


 * Embeds map projection information
 * Fast compression (about 1.5 MBytes of compressed file per second on 1 GHz processor)
 * Typical compression ratios between 1:10 and 1:100
 * Possible decompression of selected regions without the need to decompress the whole file
 * Data flow compression allows for compression of big files with small RAM requirements

There is a free library to compress images up to 500 MBytes in size. The source code is available, but you are granted the rights for evaluation purposes only. For other purposes you are required to pay royalties if the encoding capability is greater than 500 MBytes.

Packages offering support
The software packages offering support include:


 * IrfanView allows one to read and write (even bulk translated) ECW files.
 * FalconView has been enhanced by the Australian Defence Force to fully support ECW mapping. (used by US DoD and 23 allied nations)
 * Aegis3 a GIS for schools used in the UK
 * ArcGIS 8.x,9.x,10.x
 * Quantum GIS 1.8, 2.0, 2.2, 2.4
 * ArcPad v6.0
 * ArcReader
 * ArcView 3
 * AutoCAD (from version R14)
 * Carmenta Engine
 * Carmenta Engine Lite
 * ECW Header Editor 2.5
 * ERDAS IMAGINE 8.5, 8.6, 8.7, 9.2, 9.3
 * ERDAS ViewFinder 2.1
 * MapImagery Plug-in for MapInfo 6
 * Bentley MicroStation
 * Pitney Bowes MapInfo Professional
 * Paint Shop Pro
 * Adobe Photoshop 4.0, 7.0
 * ESRI ArcPad v6.0 E
 * CDA Manifold System 8.0
 * WavGen Pro by WavGen - Terratracer
 * progeCAD 2009
 * Safe Software FME
 * CARIS Easy View