Magellan F-BIDR Restoration Release Notes

Users are encouraged to provide comments to the PDS Geosciences Node if errors
are found either in data or in documentation in this archive. Please send
comments by e-mail to the PDS Geosciences Node at geosci@wunder.wustl.edu.



TODO FIX ME FROM HERE ON DOWN (ABOUT MIDRs NOW)

This document contains processing notes and errata concerning the restoration of the original PDS3 Magellan F-BIDR (Full-Resolution Basic Image Data Record) dataset. Section A of this document contains general notes and errata about the state of this PDS4 bundle, and Section B notes per release (most recent first).

******** SECTION A: General Notes/Errata ********

For more details of the conversion process and the notes here, see the User's Guide in this bundle (its LID is urn:nasa:pds:magellan_fbidr:document:fbidr_userguide).

1. F-BIDRs not converted

The PDS3 dataset consists of 5,948 F-BIDRs total. The current contents of this archive correspond to 4,157 of them. There were 568 F-BIDRs excluded because they were superseded (i.e., another F-BIDR for the same orbit but with a higher internal version number was migrated instead), 1,133 excluded because necessary files within them were corrupted (i.e., a tape-reading error or other data transfer problem renders them completely unrecoverable), and 90 excluded because necessary files within them are non-conformant (i.e., not fully matching the F-BIDR Software Interface Specification but containing data that might be recoverable). For details of which F-BIDRs fall into which category, see the Orbit Inclusion Table product in this bundle's miscellaneous collection (LID urn:nasa:pds:magellan_fbidr:miscellaneous:orbit_inclusion_table).

Future updates to this bundle may include migrated versions of the non-conformant F-BIDRs if data can be recovered from them.

2. Spatial Registration

Features on the Venusian surface are not perfectly registered from one map-projected F-BIDR image to another map-projected F-BIDR image or F-MIDR image. Imprecision, likely introduced by the ways these images were collected (e.g., left-looking vs. right-looking) or by imperfect knowledge of spacecraft pointing during the original F-BIDR creation, means that in some cases a known geographic feature will appear to be hundreds of meters to several kilometers displaced from one F-BIDR image to another. This discrepancy is largest when comparing left-looking orbits to right-looking orbits. It is recommended to coregister to a common base map, like the FMAP mosaic, to be sure of the correspondence between locations.

3. Individual Flipped Bits

It is possible that some individual bits in the PDS3 F-BIDR product data files might have been flipped at some time preceding migration to PDS4. In fbidr_4186_v2_eq, nearly all logical records list projection_origin_lon value 15.712 (corresponding to VAX floating-point value with bytes 0x659e427b). However, two of its records, those with burst_counter values 1236 and 1589, list longitude 4022.351 (corresponding to VAX bytes 0x659e467b, differing from the correct value in only one bit). (In this case, due to the redundancy of the metadata field affected, the incorrect values did not damage the integrity of the product fbidr_4186_v2_eq.)
It is unclear whether these errors originated during the original processing or while at rest on one of the many storage media this archive occupied (see Appendix A). Be warned that this may indicate that bit-level corruption occurred in the dataset, which we cannot in general detect and mitigate against (except in cases of redundant values as seen above).

4. Manually-Corrected Metadata

There were two F-BIDRs whose internal version number as recorded in FILE_12 ("Per-orbit parameters") did not match the version numbers embedded in their directory names. In these cases, we judge the numbers in the directory names to be more likely to be correct and have used them in this bundle.

 - fbidr_0025_v2_*: FILE_12 said version 1, directory name had version 2
 - fbidr_3495_v2_*: FILE_12 said version 1, directory name had version 2


******** SECTION B: Releases ********

June 26, 2026. Initial Release
------------------------------

This release contains migrated versions of the following components of 4,157 PDS3 F-BIDRs:

- FILE_12: Per-Orbit Parameters
- FILE_13: Image Data in Oblique Sinusoidal Projection
- FILE_15: Image Data in Sinusoidal Projection

Documents collection: contains scanned versions of the F-BIDR SIS and all documents the PDS Geosciences Node possesses that are referenced from it, and a new User's Guide for this bundle.

Miscellaneous collection: contains orbit_summary_table, which has the parameters from FILE_12 of all F-BIDRs, and orbit_inclusion_table, which lists the status of all F-BIDRs and why each one not in this bundle is not here.