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 Intergraph part of Hexagon AB. The lossy compression format efficiently compresses very large images with fine alternating contrast while retaining their visual quality.

In 1998 ER Mapper Ltd in Perth, Western Australia company founder Stuart Nixon, and two software developers Simon Cope and Mark Sheridan were researching rapid delivery of terabyte sized images over the internet using inexpensive server technology. The outcome of that research was two products, Image Web Server (IWS) and ECW. ECW represented a fundamental mathematical breakthrough enabling Discrete Wavelet Transforms (DWT) and inverse-DWT operations to be performed on very large images very quickly, while only using a tiny amount of RAM. For ECW patents, see US 6201897  and US 6442298 . For IWS patent, see US 6633688 . These patents were assigned to ERDAS (under a former name of Leica Geosystems Geospatial Imaging) July 29, 2007.

After JPEG2000 became an image standard, ER Mapper added tools to read and write JPEG2000 data into the ECW SDK to form the ECW JPEG2000 SDK. After subsequent purchase by ERDAS (themselves subsequently merged into Intergraph), the software development kit was renamed to the ERDAS ECW/JP2 SDK. v5 of the SDK was released on 2 July 2013.