Data Compression

Data Compression: possibilities and differences

Data compression is indispensable for managing and processing geodata. There are several compression techniques and formats, each with their own advantages and disadvantages. Below you will find an overview. To make things easy, we have already put together a software package that enables you to create every commonly used format.   

MrSID

MrSID is a compression format from Lizardtech and is based on the Wavelet compression technique. There are different versions of the MrSID format. The latest is MrSID version 3, which can be accessed by most GIS applications. The advantage of MrSID 3 over MrSID 2 is support for coordinate systems and the possibility of lossless compression. An advantage of MrSID3 over ECW is the higher quality / compression ration and the possibility of lossless compression. MrSID can be produced by the MrSID Encoder module for ERDAS IMAGINE. 

ECW

ECW is an ERDAS compression format (formerly ER Mapper) and is based on the Wavelet compression technique. ECW can be accessed by most GIS applications. The  advantage of  ECW over MrSID is teh speed with which ECW files can be created, but also read. At this moment, ECW is the fastest wavelet compression format available on the market. The wavelet technique inside ECW allows for a streaming service of the data, inside ERDAS APOLLO IWS or ADVANTAGE.  ECW files can be created using  ERDAS IMAGINE and ERDAS ER Mapper.

JPEG2000

JPEG2000 is an OGC compliant wavelet compression format. Because JPEG2000 is an open format, it can be created and read by a variety of GIS applications. JPEG2000 can be compressed and decompressed (read) faster than MrSID, but slower that ECW.  JPEG2000 has a higher quality / compression ratio than ECW, but lower than MrSID. The wavelet technique inside JPEG2000 allows for a streaming service of the data, inside ERDAS APOLLO IWS or ADVANTAGE. JPEG2000 files can be created using ERDAS IMAGINE and ERDAS ER Mapper.

NITF

NITF stands for National Imagery Transmission Format and is a standard developed by the U.S. Department of Defense (DoD) and the Federal Intelligence Community (IC). The NITF standard is comprised of multiple standards for exchanging, storing and sending raster products and raster related products. An NITF collection can consist of the raster image itself, along with related files such as overlays, subimages, symbols, vectors, labels and text. The NITF standard is included in the ISO/IEC 15444-1 standard for raster compression, because a JPEG2000 wavelet compression is possible for all raster formats inside an NITF collection. NITF can be produced using the NITF 2.1 module for ERDAS IMAGINE.

Would you like more information? Please contact us at: info@imagem.nl or +31(0)10-4200830.