NASA - National Aeronautics and Space Administration

+ NASA Homepage
+ NASA en Español
+ Contact NASA
PDS Geosciences Node, Washington University in St. Louis
Geosciences Node Data
Scheduled Maintenance
This site may be down on Thursdays between 7:00 and 9:30 pm Central Time for maintenance.

Mars Global Surveyor: MOLA PEDRs

Precision Experiment Data Records

PEDRs are generated from the raw altimetry profile data (AEDRs) with precision orbit corrections applied. They are time-ordered binary tables with attached PDS labels.

Tools for Use with PEDR Products

Mars Orbital Data Explorer - accepts queries of PEDR products by latitude, longitude, altitude, orbit, and time, and returns the selected altimetry data in tabular form, as a binned image, or as shapefiles for use with GIS tools.

IDL and Fortran software is available to read and extract data from PEDR files.

PEDR Data Online

Use the links below for direct access to any part of the MOLA PEDR archive.

AAREADME.TXT Introduction to the archive
ERRATA.TXT Notes and errata for the archive
INDEX directory An index to all PEDR products
DOCUMENT directory PEDR documentation
CATALOG directory PDS catalog information, including descriptions of the data set and instrument, along with references
SOFTWARE directory Software to read PEDR binary data files
LABEL directory Descriptions of data columns in PEDR files
DATA directories PEDR data directories

Note on PEDR Processing Versions

The processing software used to generate MOLA PEDRs was updated as better orbit information became available during the mission. The processing version of a given PEDR is indicated by the last character of the file name (before the period). For example, AP10146L.B is version L. (Versions increase alphabetically.) PEDRs processed with different software versions have only minor differences, but users should be aware that the multiple versions exist. Processing version L is the last version, released May 27, 2003. Version L uses IAU2000 planetocentric coordinates, incorporates crossover analysis of individual profiles, and is referenced to the latest Mars gravity model.

All PEDR products on this web site have been reprocessed to version L, to provide a complete set of PEDRs with a consistent processing history. These products are intended to replace previously released PEDRs, found on CD-ROM volumes MGSL_0001 through MGSL_2054.

The first two MOLA CD-ROM volumes, MGSL_0001 and MGSL_0002, and the MGS Sampler CD contained versions of PEDRs in ASCII tables as well as binary. This proved to be an impractical storage format, so later volumes did not include the ASCII versions. The data in the ASCII files have been superseded by the present PEDR data set.

Back to MOLA page


PDS Nodes PDS Atmospheres Geosciences Imaging NAIF PPI Rings Small Bodies
FirstGov Logo
+ Freedom of Information Act
+ NASA Strategic Plans
+ NASA Privacy Statement, Disclaimer, and
   Accessibility Certification

+ Copyright/Image Use Policy
Curator: Jennifer Ward
NASA Official: Paul Byrne
Last Updated:
+ Comments and Questions