Server-side use of ECW technology requires a valid, paid license that is issued by ERDAS.
This is true of any type of server product, whether it be commercial, proprietary or "open source".
Typically, the software company that made the product would have purchased a "Software Development Toolkit" from us to allow them to use ECW in their server.
If you have a paid license, you are able, from a legal and licensing stand point, use ECW files and technology on your third-party server application....
I would like to explain, in "plain English", what is required when using the ECW technology in your applications. The ECW technology is contained within a "software development kit", the ECW JPEG 2000 SDK. This kit provides read and write ability for both ECW and JPEG 2000 files.
There is no difference in the license use terms between "code-closed" or "open source" applications. Both types of applications are treated the same under the ECW technology use agreement (the End-User License Agreement or EULA). For desktop applications, at no cost, you can:
- Read any size of ECW file....
If you create web-based GIS websites without using the browser plug-in that provides ECWP ability you need to be aware of something very important.
All modern web browsers impose a security restriction that prevents a script or application from making a connection to any web server other than the one the web page originally came from.
So, if your JavaScript file comes from http://iws.erdas.com/ it can only talk to resources from http://iws.erdas.com/. 
It cannot access resources from another domain like http://www.yahoo.com/ or even http://www.erdas.com/ . 
This can present a challenge when we use a purely HTML and JavaScript front-end to imagery or GIS data. We may have these resources on different servers and domains. For example, I might serve my web page (html, JavaScript, etc) and imagery from one server, but my GIS information from a different server. Given the above limitation, this isn't available by using just a browser. So, how do we get around this.
To be able to request data from a source apart from the scripts orginating domain, we use "server-side proxys". These server-side applications reside on the domain that the javascript is served from....
If you are wondering how to create a website using Optimized Tile Delivery, or OTD, I have some very good news for you.
OTD sites are created using the same website API that are used to create other Image Web Server sites. It is exactly the same as when you are creating DHTML sites, and only marginally different from creating ECWP high-speed streaming sites.
The only real difference is that the file you are passing is a .OTDF file.
So, to create your OTD enabled site, you just need to force the page to use the DHTML control, by setting the correct browser cookie:
setCookie("NCSPluginInstallMethod", "HTML");
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If you are using the "NCSCreateView" function, that is all you need to do.
If you construct the map control directly, you would need to make sure that you instantiate the NCSJSView, for example:
document.ECWView1 = new NCSJSView("100%", "100%"); | document.ECWView1.SetCallbackName("onPercentComplete", "myprogress");
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So, if you have an ECWP enabled website, if you want to experiment, with OTD, you only have to make these simple changes to your code.
The one thing that you will want to be aware of is the "cross-domain scripting" rule. Essentially, when using browsers are limited to calling resources only from their local domain. For example, JavaScript on iws.erdas.com can only call resources from iws.erdas.com. In our situation the resources that we are interested in our the image tiles from IWS, or perhaps a GIS Server. Both of these items may not be on the same server. When using ECWP, we don't have to worry about this, because the ECWP control is able to request information from different servers. It is when you are only using JavaScript that you have this limitation.
So - in order to get around this limitation when working with JavaScript - you need to pass all external requests through a server-side component. IWS has a built in server-side component that makes it very easy to do just this.
In the IWS Admin Console: - Login to the server
- Select > Tools
- Select > Options
- Select > Proxy
In the presented dialog box list all the external websites you would like to access and apply your changes....
Imagery can be stored, and served, from anywhere on your network.
You do need to be aware of some simple network and security considerations.
Just like you "login" to your computer, so does the applications that you use. Sometimes they just "borrow" your login, but other times they use any number of system defined "user details". This is particularly the case for any server application.
Image Web Server operates under a defined user account. This account must have “read” access to the image files in order to serve them....
For Windows based installations, before installing Image Web Server you will want to check that you have Internet Information Services installed.
Internet Information Services is the free web server that is packaged with the windows operating systems....
Once again, Chris Tapley has been busy, and has developed some simple ways to add IWS data to ArcGIS based websites.
The integration is in two parts: - ArcGIS WebADF ImageX/OTDF DataSource
- ECWP and ImageX/OTDF layers for the ArcGIS REST JavaScript API
The “ArcGIS WebADF ImageX/OTDF DataSource” requires the following to be installed on the machine: - ArcGIS Server 9.3 .NET edition
- Microsoft Visual Studio 2005
It is possible to just deploy the Web Mapping Application to an ArcGIS server machine without VS2005 installed, but for development purposes VS2005 needs to be there....
ECWP is a high-speed streaming imagery protocol provided by Image Web Server.
ECWP allows a single, entry-level server, to provide 1000's of gigabytes of image data to thousands of concurrent users that are using different web, desktop, GIS, server or mobile applications....
OpenLayers is an extremely popular framework for creating web-browser based mapping applications.
A developer in our Perth, Australia office, Chris Tapley, has created a "ECWP Layer Type" for OpenLayers. So, if you are using, or want to use, OpenLayers, you can now easily add an ECWP layer.
An example of this can be found at: http://iws.erdas.com/OpenLayers_and_iws.htm
If you want to create your own OpenLayers / ECWP enabled maps you can download the code: openlayers_and_iws.zip....
If you are installing IWS on Windows XP - as a quick evaluation - you might want to increase the connection limits of IWS.
Windows XP Professional runs IIS version 5.1 and comes with a 10 connection limit....
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