What is a CDF file?
A file with .cdf extension is an XLM based information distribution file format that was used to publish frequent updates as “channels”. The information is published from any web server and is automatically delivered to computers with compatible receiving programs such as web browsers. Users subscribe to active channels and have scheduled updates delivered to their desktop. CDF files were earlier used in conjunction with Microsoft’s Active Channel, Active Desktop and Smart Offline Favorites technologies.
CDF File Format
CDF files are saved as XML files that is a generic web file format for exchange of information. CDF file format is an old format now and was never widely adopted. In comparison to this, the Netscape’s RSS was more famous and widely used.
CDF File Format Example
The following is a generic exmaple of the CDF file format.
<?xml version="1.0" encoding="UTF-8"?>
<CHANNEL HREF="http://domain/folder/pageOne.extension"
BASE="http://domain/folder/"
LASTMOD="1998-11-05T22:12"
PRECACHE="YES"
LEVEL="0">
<TITLE>Title of Channel</TITLE>
<ABSTRACT>Synopsis of channel's contents.</ABSTRACT>
<SCHEDULE>
<INTERVALTIME DAY="14"/>
</SCHEDULE>
<LOGO HREF="wideChannelLogo.gif" STYLE="IMAGE-WIDE"/>
<LOGO HREF="imageChannelLogo.gif" STYLE="IMAGE"/>
<LOGO HREF="iconChannelLogo.gif" STYLE="ICON"/>
<ITEM HREF="pageTwo.extension"
LASTMOD="1998-11-05T22:12"
PRECACHE="YES"
LEVEL="1">
<TITLE>Page Two's Title</TITLE>
<ABSTRACT>Synopsis of Page Two's contents.</ABSTRACT>
<LOGO HREF="pageTwoLogo.gif" STYLE="IMAGE"/>
<LOGO HREF="pageTwoLogo.gif" STYLE="ICON"/>
</ITEM>
</CHANNEL>
Key Characteristics of the CDF File Format
| Characteristic | Description |
|---|---|
| File Extension | .cdf |
| Dual Identity | The .cdf extension represents two major, unrelated formats: one for scientific data storage (NASA) and one for interactive technical documents (Wolfram). |
| Self-Containment | Both formats aim to be self-contained. NASA’s CDF bundles data with its metadata; Wolfram’s CDF bundles content with its computation engine. |
| Standardization in Science | NASA’s CDF is an enduring, community-supported standard in space and geophysical sciences, ensuring long-term data accessibility and interoperability. |
| Interactivity Paradigm | Wolfram’s CDF redefines a document from a static snapshot into an interactive application, bridging the gap between publication and software. |
| Library-Dependent Access | Both formats generally require specific software libraries (NASA CDF Library or Wolfram CDF Player/Mathematica) for full creation, reading, and manipulation, though some data can be exported to more common formats. |
FAQ
Q1: How do I know which type of CDF file I have?
A: Context is key. If it’s from a scientific dataset or NASA mission, it’s likely the Common Data Format. If it’s an interactive textbook, report, or dashboard, it’s probably the Wolfram Computable Document Format. You can also try opening it with the respective free viewer.
Q2: What program opens a NASA CDF file?
A: Use the free CDF Toolkit (including the CDF Library and tools like cdfedit), or specialized scientific software like IDL, MATLAB, or Python with the spacepy or cdflib libraries.
Q3: Can I open a Wolfram CDF without Mathematica?
A: IYes, using the free Wolfram CDF Player, which allows you to view and interact with, but not edit, CDF documents.
Q4: Is the CDF format secure?
A: Wolfram CDFs run in a sandboxed environment for safety. As with any file that can contain executable code, you should only open CDFs from trusted sources.
Q5: Can I convert a CDF file to a PDF?
A: For Wolfram CDF, you can export a static snapshot to PDF, but all interactivity will be lost. For NASA CDF, you would extract and plot the data, then save the plot as a PDF; the raw data structure itself doesn’t convert directly.
