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PDS Geosciences Node, Washington University in St. Louis
Geosciences Node Data
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This site may be down on Thursdays between 7:00 and 9:30 pm Central Time for maintenance.

About PDS4

PDS4 is a revision to the PDS standards for archiving, replacing PDS3 which had been in place for many years. PDS4 is designed to produce higher quality, more accessible archives using modern software capabilities.

Both PDS3 and PDS4 specify the contents of a quality archive, including data, documentation, and ancillary material, with metadata for each product stored in a PDS label.

PDS4 data types are fewer, simpler, and more rigorously defined as compared to PDS3. While PDS3 labels used a keyword=value format, PDS4 labels are written in XML (eXtensible Markup Language), enabling more complete and consistent metadata, and allowing the use of existing XML software tools.

Planetary missions confirmed for flight after November 1, 2011 are required to archive in PDS4. Active missions that were archiving in PDS3 before that date have continued to use the PDS3 standard. These archives will be converted to PDS4 according to the PDS migration policy. Proposals to new R&A programs should include archiving in PDS4.

PDS4 archives on this web site are indicated by "(PDS4)" next to the link to the archive, and by an archive directory name beginning with "urn-nasa-pds".

Data processing levels are specified differently in PDS4. In PDS3 processing levels were given numbers, but there was confusion because two different sets of numbers were in common use. PDS4 uses the following descriptive terms.

Processing Level



An encoded byte stream used to transfer data from one or more instruments to temporary storage where the raw instrument data will be extracted. PDS does not archive telemetry data.


Original data from an instrument. If compression, reformatting, packetization, or other translation has been applied to facilitate data transmission or storage, those processes will be reversed so that the archived data are in a PDS-approved archive format.

Partially Processed

Data that have been processed beyond the raw stage but which have not yet reached calibrated status.


Data converted to physical units, which makes values independent of the instrument.


Results that have been distilled from one or more calibrated data products (for example, maps, gravity or magnetic fields, or ring particle size distributions). Supplementary data used to interpret observational data, such as calibration tables or tables of viewing geometry, should also be classified as derived data if not easily matched to one of the other categories.

For more information:

PDS Concepts Document – The view from 10,000 feet. Read this first.

PDS4 Data Standards – The primary web page for PDS4 information.

The Data Provider’s Handbook – Step-by-step detailed instructions for building a PDS4 archive.

The PDS Small Bodies Node Wiki for PDS4 – Even more detailed instructions on specific topics.

Please contact us with questions or if you need assistance:


PDS Nodes PDS Atmospheres Geosciences Imaging NAIF PPI Rings Small Bodies
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Curator: Jennifer Ward
NASA Official: Paul Byrne
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