An ECW file consists of an image designed for use with geospatial data. The containing image is actually compressed image created in the Enhanced Compression Wavelet format. ECW files are generally used for storing satellite map projection and aerial images. To support geospatial applications, map projection information can be embedded into the ECW files.
ECW file format
ECW is a proprietary image format based on wavelet compression; optimized for satellite imagery and aerial photography. This format is now owned by Intergraph part of Hexagon AB but basically it was developed by Earth Resource Mapping. ECW is a lossy compression format which compresses large size images with fine alternating contrast while retaining their visual quality.
Here are some typical properties of ECW format:
Map projection information can be added into the ECW file format to support geospatial applications.
Image data of up to 65,535 bands including layers or colors can be compressed into the ECW file format at a rate of over 25 MB per second.
The ECWP protocol is an efficient streaming protocol used to transmit ECW and JPEG2000 images over networks.
A fast SDK supporting ECW and JPEG2000 is available for no charge for desktop implementation for Linux, Windows and MacOSX