Frequently Asked Questions

If you don't see your question here, check the Geosciences Node Forums to see if it's been discussed there. There are forums for announcements, data users, data providers, Analyst's Notebook users, and Orbital Data Explorer users. You may post your question in one of the forums (after signing up for a free account), or you may email it to geosci@wunder.wustl.edu. 

What is PDS?

PDS is the Planetary Data System, a NASA-funded organization that archives and distributes planetary data to the science community. It exists as a geographically distributed set of Nodes, each responsible for a particular kind of data. Read more on the Background page at this site and on the PDS Home Page.

How much does it cost to obtain PDS data?

Data sets archived in the PDS are in the public domain. Almost all PDS data sets are online and may be downloaded by anyone for free.

Can I use FTP to download data?

Yes. Read about Anonymous FTP Access.

What if the data set I want is not online?

Ask the PDS Node responsible for the data set to put it online for you.

What if the data set I want is too big to download?

Ask the PDS Node responsible for the data set whether you can receive the data another way. For example, the Geosciences Node can sometimes ship data on a user-provided disk drive.

I downloaded some files but I think they may have been corrupted during the transfer. How can I tell?

Compare the checksums of the files on your end to the checksums on the Geosciences Node server. Read more about checksums here.

Are there any restrictions on the use of PDS data?

PDS data sets are classified TSPA (Technology and Software Publicly Available) by the U.S. Department of Commerce, Bureau of Export Administration, and may be exported outside the United States as public open literature. When PDS data sets are used in published literature or other applications, they should be cited appropriately (see below).

Documents in PDS archives are also freely available for downloading. Documents by JPL authors may carry a copyright statement, which is not intended to restrict access. These documents are covered by the JPL Data and Documentation Use Policy for PDS.

How should PDS data sets be cited in scientific literature?

PDS data sets should be cited in the same way that published research is cited. See Citing PDS4 Data or Citing PDS3 Data on the general PDS web site. If you need a DOI to include in a citation, see Geosciences Node DOIs.

I don't understand the archives I see online. What are all these files?

Please read Help for Data Users, which explains the standard structure followed by all PDS archives.

How do I display a PDS image?

A PDS image is stored as a binary array with a plain-text PDS label either embedded at the beginning of the file or in a separate file. The label contains the information needed to enable image display programs to read and display the image. PDS4 Viewer is a free visualization tool produced by the PDS Small Bodies Node (SBN) for PDS4 data that supports viewing images, tables, spectra, and arrays. NASAView is a free program for viewing PDS3 images. PDS deliberately does not use any commercial or proprietary formats to archive image data, in order to ensure the long-term viability of the data.

A guide to viewing PDS Images and exporting them to common image formats is available here: Viewing PDS Images and Exporting to Other Formats.

An example Jupyter Notebook that uses Python to view a PDS image and save it as a browse image can be found here.

I have heard that PDS does not archive data that have been compressed, as in JPEG images. Why not?

In general data products that have been lossy-compressed -- that is, compressed in such a way that some of the original data are not recoverable -- are not suitable for PDS archives. There are exceptions. Please read the Policy for Use of Compression in PDS Archives. Sometimes compressed data such as JPEG images may appear in an archive but not as the primary archive product. 

 I have been asked to help review a new PDS data set. What do I do?

The input of peer reviewers is very important to us. Please read the Help for Data Reviewers, and if you still have questions, email us at geosci@wunder.wustl.edu. 

I am writing a proposal that includes using PDS data and/or submitting new data to PDS. What do I do?

Please read Help for Proposers for some guidelines.

I have to put my science data in a public repository so that my article can be published. Will PDS take my data?

If you are the author of an article for a journal that requires you to archive your data in a public repository, you may not wish to undertake the steps involved in submitting the data to the PDS, steps that include labeling, documenting, and possibly reformatting the data products. The effort involved may not be justified for a small, simple data set. In this case we recommend that you submit the data to one of the many available online data repositories, such as figshare (figshare.com) or Dataverse (dataverse.org). On the other hand, if you believe your data would be a useful addition to the PDS, and you are willing to put in the work and submit the data to a peer review, please send your request to geosci@wunder.wustl.edu.

I have some questions about LOLA data from the Lunar Reconnaissance Orbiter mission.

Visit the LOLA Frequently Asked Questions page.

I'm having trouble displaying Mars Global Surveyor MOLA map products in ENVI and in ArcGIS.

ENVI header files are available for use with MOLA map products (MEGDRs). Look in the EXTRAS directory of the MOLA MEGDR archive.

Last updated December 11, 2019.