ECW ( Wavelet compression for digital imagery and image web server from earth resource mapping pty. Ltd.)


Using Compressed Imagery with GIS/CAD/Office application
When disturbing imagery, an important consideration is the ultimate ability of users to access and effectively use the imagery.

Studies have continually shown that the ability to be able to directly access imagery, without having to import it first, and which geographic information preserved, consistently ranks as the highest requirement by imagery users in the GIS, CAD and office software environments.

There is a range of free plugins for common GIS/CAD/MS office applications, which directly read compressed ECW image files. Plugins are available than enable products to directly read compressed image files, for products including:

AutoCAD and AutoCAD MAP 3
Arc View 3.1
MapInfo 4.0/4.5/5.0
Microsoft Office (Word, Excel, etc)
ER Mapper
Photoshop
Standalone image viewing


When distributing imagery, these plugins can be distributed with your imagery, free of charge. Each plugin is typically 2MB to 3MB in size prior to installation, and is available as a single .EXE file that uses InstallShield to install the plugin.

The Image Web Server (IWS)

The Image Web Server has been designed by Earth Resource Mapping for the following:
  1. Serve large GB or TB (1,000 GB) sized) images via the Internet or Intranet
  2. Enable users to access the imagery via heir existing applications including web browsers, MS Office, GIS and CAD Software Products.
  3. Enable users to access the imagery via slow modem links.
  4. E-Commerce revenue by charging access subscription fees or charging for image sub-set downloads
  5. Tightly integrate imagery with your existing web based HTML and database applications.
The Image Web Server can serve many different types of imagery including airphotos, high-resolution satellite images, digital terrain models, Radar etc.



The need for the Image Web Server
Currently the large size of image data and network bandwidth limitations preclude making imagery available over a network, in particular the Internet. Typically, sites with imagery would post thumbnail JPEG compressed images for viewing on-line. Distribution of larger images is done via CD. Apart from the time taken and inconvenience, other problems are
  • If the original image is updated, it has to be re-distributed via CD. Users can never be certain that they have the latest version. This is not very satisfactory for industries that rely on up to date information.
  • Users can generally not request subsets of the image. At best they can ask for set portions of the image that contain the part they require. This means that they often pay for data that they do not need.
The Image Server uses ER Mapper's ECW V2.0 wavelet compression technology to minimize the size of images so that they can easily be propagated over a network with no discernable loss in quality. On the client side, the user can access the data via Internet Explorer and Netscape web browsers, or from within applications like ER Mapper, MapInfo, and Microsoft Office Tools.

Various organizations like Image Data Sales and Distribution, Real Estate Agencies, local Govt. Bodies, Defense forces, Govt. regulatory bodies etc. could benefit from usage of ECW and IWS.

The Internet Web Server makes it possible to supply up to data imagery to many different types of recipients over diverse media. Also, since the imagery is encapsulated, it can be encrypted and sent over secure links with no degradation or corruption.

Solutions using Image Web Server Technology
The image Web Server solves the problems of serving large image on the Internet or Intranet by combining the powerful ECW compression with image sub setting. It not only compresses the images, but also only transfers the portion of the image currently being displayed by the client.

Compression Products

You can use any of the following products to compress imagery for the Image Web Server.
  • ER Mapper 6.1. This enables you to compress very large (TB sized) images, and can also perform image registration, balancing, mosacing and enhancement as part of the compression process.
  • ECW compression. This is a free compression program available from the ER Mapper web site www.ermapper.com that can compress images upto 500 MB in size.
  • ECW V2.0 plugin for photoshop is available from www.ermapper.com and can compress images upto 500 MB in size.
  • Custom application developers can use the ECW v2.0 Compression SDK, available at no fee and royalty free, from www.ermapper.com to create custom compression applications.
Various companies have announced support for a range of applications to compress imagery into the ECW Vr.0 format. See www.ermapper.com for the latest list of products known to support the format.

All brands, company names and product names are trademarks or registered tardemarks of their respective holders.


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