ECW (file format)

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Enhanced Compression Wavelet

Filename extension	.ecw
Developed by	Earth Resource Mapping
Latest release	3.3
Type of format	Image 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.

Contents 1 Properties 2 Packages offering support 3 References 4 External links

[edit] 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.^[1] The source code is available, but you are granted the rights for evaluation purposes only.^[2] For other purposes you are required to pay royalties if the encoding capability is greater than 500 MBytes.^[3]

[edit] 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 and 9.x
• 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

[edit] References

1. ↑ "ECW JPEG2000 Codec SDK". Erdas, Inc.. http://www.ermapper.com/tabid/84/currentid/1142/default.aspx. Retrieved 2009-05-23. 
2. ↑ Erdas, Inc. (Plain text file). ER MAPPER IMAGE COMPRESSION SDK USAGE AGREEMENTS. Erdas, Inc.. "You are granted the rights to use the ER Mapper Image Compression SDK for evaluation purposes only." 
3. ↑ Erdas, Inc. (Microsoft Word). ECW JPEG 2000 SDK Royalty Agreement. Erdas, Inc.. "... End Applications for Commercial Use, which requires You to pay royalties to Erdas on your copies of the Software and on certain distributed End Applications." 

[edit] External links

• GISdevelopment.net - ECW (Wavelet compression for Digital Imagery and Image Web server)
• Ueffing - Wavelet based ECW image compression (PDF)
• Large (over 100 GByte) ECW files displayed online

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