Lunar Reconnaissance Orbiter

Lunar Orbiter Laser Altimeter

Archive Volume

Software Interface Specification










Version 2.6

December 15, 2015

SIGNATURE PAGE

Prepared by:



_________

Gregory A. Neumann Date

LOLA Instrument Co-Investigator

GSFC Code 698



Reviewed by:



_________

David E. Smith Date

Principal Investigator, LOLA Instrument

GSFC Code 690.5





Approved by:



_________

Stan Scott Date

LRO Project Science Data Manager

GSFC Code 451



Concurred by:



_________

Susan Slavney Date

PDS Geosciences Discipline Node





_________

Ed Grayzeck Date

GSFC Code 690.1, PDS Program Manager


TABLE OF CONTENTS

1.Introduction 1

1.1.Purpose and Scope 1

1.2.Content Overview 1

1.3.Applicable Documents and Constraints 1

1.4.Relationships with Other Interfaces 2

2.Archive Volume Contents 3

2.1.Root Directory Contents 3

2.2.DATA Directory Contents and Naming 3

2.3.INDEX Directory Contents 6

2.4.DOCUMENT Directory Contents 6

2.5.CATALOG Directory Contents 7

2.6.LABEL Directory Contents 8

2.7.CALIB Directory Contents 8

2.8.GEOMETRY Directory Contents 8

2.9.BROWSE Directory Contents 9

2.10.EXTRAS Directory Contents 9

3.Archive Volume Format 10

3.1.File Formats 10

3.1.1.Document File Format 10

3.1.2.Tabular File Format 11

3.1.3.PDS Label Format 11

3.1.4.Catalog File Format 11

3.1.5.Science Data File Formats 11

4.Archive Volume Generation 15

4.1.Data Transfer and Validation Methods 15

4.2.Data Product Sizes and Delivery Rates 15

4.3.Interface Media Characteristics 15

4.4.Backup and Duplicates 16

4.5.Labeling and Identification 16

5.Support Staff and Cognizant Persons 17

6.Appendices 18

6.1.Contents of the RDRINDEX.LBL file 18



TABLES AND FIGURES

Table 1. LOLA standard Data Product Datasets 1

Table 2. Description of files in ROOT Directory 3

Table 3. Description of files in INDEX Directory 6

Table 4. Description of files in DOCUMENT Directory 6

Table 5. Description of files in CATALOG Directory 7

Table 6. Description of files in LABEL Directory 8

Table 7. Description of files in CALIB Directory 8

Table 8. Description of files in GEOMETRY Directory 9

Table 9. Description of files in BROWSE directory 9

Table 10. Description of files in EXTRAS directory 10

Table 11. Equirectangular map-projected digital elevation models 12

Figure 1: Equirectangular map projection. Lines show notional tiling subdivisions of LDEM_256 (bold), LDEM_512 (fine), and LDEM_1024 (dashed). 13

Table 12. Polar map-projected digital elevation models, N/S 13

Figure 2: Polar stereographic map projection from 45°N to pole. Circles show outlines of LDEMs at various resolutions (innermost circles enclose 10 and 5 meter DEMs). 14

Table 13. Standard Product Sizes and Delivery Rates 15

DOCUMENT CHANGE LOG


Change

Date

Affected Portions

Ward's suggested changes adopted, red text gone.

3/24/08

acronyms, all sections

Revisions by S. Slavney

5/19/08

1.2, 1.3, 2.3, 2.4, 2.5, 2.7, 2.9, 3.1.3, 4.1, 4.2, 4.4, 4.5 revised. BROWSE and EXTRAS directory sections deleted.

Revisions to product descriptions

8/14/08

3.16

Added BROWSE description

10/22/08

2.10

Added description of INDEX table columns

10/26/08

2.3, 6

Added Signature Page

10/26/08

ii

Version updated to October 22, 2008 Version 2

10/26/08

1.3

Section 2.1, second sentence, “are”, removed

10/26/08

2.1

Section 2.11, ISO 9660 standards conformance

10/26/08

2.11

Additions to Applicable Documents

10/26/08

1.3, 3.1.3

Volume ID clarified

10/26/08

4.5

Reference radius choices clarified

10/26/08

3.1.6

Table headings added

10/26/08

all

Table entries are punctuated if sentences.

10/26/08

all

Column for resolution date added to TBD items

11/17/08

v

Description of the PDS NAIF Node and SPICE

11/17/08

vi, 2.9

Figures 1 and 2 - DEM subdivisions added

11/17/08

3.1.6

INDEX table column descriptions clarified

11/17/08

6.1

Explanation of relationships with radio science

11/17/08

1.4

Revised filespecs of EDR, RDR, GDR polar

08/28/09

2.2, Table 13

Edited for readability, kj

02/19/10

All sections

JPEG2000 format for GDR products adopted

02/22/10


Product subdirectories revised

09/16/10


LOLA_GDR product and tiling specs revised

11/10/10

Section 3.1.6, Table 12

Version and filename updates

12/10/10

All

Updated, added SLDEM, FLOAT_IMG, LOLA_RADR – k jha

12/22/15

All

Updated to reflect actual contents of archive – SHS

1/12/16

All

Updated GEOMETRY. SOFTWARE moved to EXTRAS. Renamed instrument kernel file – k jha

02/23/16

2.8, 2.10


TBD ITEMS


Section

Description

Resolution Date





ACRONYMS AND ABBREVIATIONS


ASCII

American Standard Code for Information Interchange

DVD-ROM

Compact Disk or Digital Video Disk – Read-Only Memory

EDR

Experiment Data Record

GB

Giga Byte

GDR

Gridded Data Record, as elevation with respect to a sphere

GSFC

Goddard Space Flight Center

HTML

HyperText Markup Language

ILRS

International Laser Ranging Service

ISO

International Standards Organization 9660/UDF standards

JPEG

Joint Photographic Experts Group image format

JP2

JPEG2000 standard image format suffix

JPL

Jet Propulsion Laboratory

LOLA

Lunar Orbiter Laser Altimeter

LRO

Lunar Reconnaissance Orbiter

MB

Mega Byte

NAIF

Navigation and Ancillary Information Facility of the PDS

NSSDC

National Space Science Data Center

PDF

Portable Document Format

PDS

Planetary Data System

PNG

Portable Network Graphics image format

RADR

Reduced Albedo Data Record

RDR

Reduced Data Record

SHADR

Spherical Harmonic ASCII Data Record

SIS

Software Interface Specification

SLDEM

Selene-LOLA Digital Elevation Model

SOC

Science Operations Center

TBD

To Be Determined

URL

Universal Resource Locator

UTC

Coordinated Universal Time

GLOSSARY


Archive – An archive consists of one or more data sets along with all the documentation and ancillary information needed to understand and use the data. An archive is a logical construct independent of the medium on which it is stored.

Archive Volume, Archive Volume Set – A volume is a unit of media on which data products are stored; for example, one ISO 9660 CD-ROM or DVD-ROM (Applicable document #9). An archive volume is a volume containing all or part of an archive; that is, data products plus documentation and ancillary files. When an archive spans multiple volumes, they are called an archive volume set. Usually the documentation and some ancillary files are repeated on each volume of the set, so that a single volume can be used alone.

Catalog Information – Descriptive information about a data set (e.g. mission description, spacecraft description, instrument description), expressed in Object Description Language (ODL) suitable for loading into a PDS catalog.

Data Product – A labeled grouping of data resulting from a scientific observation, usually stored in one file. A corresponding product label identifies, describes, and defines the structure of the data. An example of a data product is a planetary image, a spectrum table, or a time-series table.

Data Set – An accumulation of data products. A data set together with supporting documentation and ancillary files is an archive.

Digital Elevation Model – A raster map of height with respect to lunar center of mass. The elevation may be shape values (absolute radii) or relative to a sphere of constant radius.

Profile – A time-ordered set of altimetry and allied data.

SPICE – An information system maintained by the PDS NAIF Node to assist scientists in planning and interpreting scientific observations from space-based instruments.

Standard Data Product – A data product generated in a predefined way using well-understood procedures, processed in "pipeline" fashion. (Data products that are generated in a nonstandard way are sometimes called special data products.)

1.Introduction

1.1.Purpose and Scope

This Software Interface Specification is intended to be used by those who wish to understand the format and content of the Lunar Reconnaissance Orbiter (LRO) Lunar Orbiter Laser Altimeter (LOLA) Archive. Typically, these individuals are software engineers, data analysts, or planetary scientists.

The specifications in this document apply to all LOLA standard product archive volumes that are generated by the LOLA investigation for the LRO Project.

Table 1. LOLA standard Data Product Datasets

Product Type

Data Set ID

Description

LOLA_EDR

LRO-L-LOLA-2-EDR-V1.0

Raw altimetry data

LOLA_RDR

LRO-L-LOLA-3-RDR-V1.0

Calibrated geolocated altimetry data

LOLA_RADR

LRO-L-LOLA-3-RADR-V1.0

Calibrated, geolocated active radiometry data

LOLA_GDR

LRO-L-LOLA-4-GDR-V1.0

Gridded (raster) digital elevation and related models

LOLA_SHADR

LRO-L-LOLA-5-SHADR-V1.0

Spherical harmonics gravity/topography models

SLDEM2015

LRO-L-LOLA-4-GDR-V1.0

Gridded LOLA data co-registered with SELENE's Terrain Camera data


1.2.Content Overview

This Software Interface Specification (SIS) describes the format, content, and generation of the LRO LOLA Instrument Data Archive. The Archive Volume is comprised of raw telemetry, calibrated, reduced and resampled, and processed data. RDR and higher level data are continually reprocessed with higher accuracy during the course of the LRO mission, and the updated versions logically supersede earlier versions. Such data include gridded data and spherical harmonic models, each of which are based on the accumulated data as of the close of the corresponding production cycle, approximately quarterly. LOLA data products are generated by the LOLA Science Operations Center (SOC) at GSFC. Section 2, Archive Volume Generation, describes the procedure for transferring data products to archive media. Section 3, Archive Volume Contents, describes the structure of the archive volumes and the contents of each file. Section 4, Archive Volume Format, describes the file formats used on the archive volumes. Finally, Section 5, Support Staff and Cognizant Persons, lists the individuals responsible for generating the archive volumes.

1.3.Applicable Documents and Constraints

This Archive Volume SIS is intended to be consistent with the following documents:

  1. Lunar Reconnaissance Orbiter Project Data Management and Archive Plan, 431-PLAN-00182.

  1. Lunar Reconnaissance Orbiter Lunar Orbiter Laser Altimeter Experiment Data Record Software Interface Specification (LOLA EDRSIS) V2.4, August 28, 2009.

  2. LOLA Science Operations Center Requirements Document, Revision B, October 25, 2006.

  3. LOLA Instrument Team Data Management and Archive Plan, Aug. 31, 2006.

  4. Memorandum of Agreement for Establishment of the LRO LOLA Data Node Between the PDS Geosciences Node, Washington University, St. Louis, Missouri, and the Lunar Reconnaissance Orbiter (LRO) LOLA Instrument Team, Goddard Space Flight Center, Greenbelt, Maryland, October 27, 2006.

  5. LRO LOLA Science Team and PDS Geosciences Node Interface Control Document, October 9, 2006.

  6. Planetary Data System Archive Preparation Guide, August 29, 2006, Version 1.1, JPL D-31224.

  7. Planetary Data System Standards Reference, March 20, 2006, Version 3.7. JPL D-7669, Part 2.

  8. ISO 9660-1988, Information Processing - Volume and File Structure of CD-ROM for Information Exchange, April 15, 1988.

  9. A Standardized Lunar Coordinate System for the Lunar Reconnaissance Orbiter, LRO Project White Paper, 451-SCI-000958, Version 3, January 30, 2008.

  10. Lunar Reconnaissance Orbiter Lunar Orbiter Laser Altimeter Reduced Data Record and Derived Products Software Interface Specification (RDRSIS), V2.53, September 16, 2010.

1.4.Relationships with Other Interfaces

The LOLA instrument is a component of the Laser Ranging system on board LRO. This Archive Volume SIS could be affected by changes to the design of the LRO Data Management System. The LRO radio tracking data are generated by the LRO Ground Data System, but there is no formal Radio Science investigation. These data are received by the LOLA Science Operations Center and are being archived separately from the LOLA Measurement Investigation. The Laser Ranging data will be archived as part of a Radio Science PDS archive on a best-efforts basis, and will also be maintained by the ILRS through the Crustal Dynamics Data Information System.

2.Archive Volume Contents

This section describes the contents of the LOLA Archive volumes, including the file names, file contents, file types, and organization responsible for providing the files.

2.1.Root Directory Contents

Files in the ROOT Directory include an overview of the archive, a description of the volume for the PDS Catalog, and a list of errata or comments about the archive. The following files and directories are contained in the ROOT Directory.

Table 2. Description of files in ROOT Directory

File Name

File Contents

File Provided By

AAREADME.TXT

Volume content and format information

LOLA Instrument Team

ERRATA.TXT

A cumulative listing of comments and updates concerning all archive volumes published to date

LOLA SOC

VOLDESC.CAT

A description of the contents of this volume in a PDS format readable by both humans and computers

LOLA SOC

/BROWSE

Images and hyper/text files related to DATA

LOLA SOC

/CATALOG

Descriptions of the data set, instruments, spacecraft, and mission as found in the PDS Catalog

LOLA SOC and Geosciences

/CALIB

Calibration documents, tables, notes

LOLA SOC

/DATA

Directories for standard product types

LOLA SOC

/DOCUMENT

Software interface specification files and labels

LOLA SOC

/EXTRAS

Tools and useful “value-added” context material such as Celestia textures, not crucial to understanding the dataset

LOLA SOC

/GEOMETRY

Instrument orientation with respect to spacecraft

LOLA SOC

/INDEX

Files provided to help the user locate products on this archive volume and on previously released volumes in the archive

Geosciences

/LABEL

Descriptions of data file formats, referenced by PDS labels

LOLA SOC



2.2.DATA Directory Contents and Naming

Under the DATA directory there is a separate subdirectory for each type of product. The subdirectories may include one or more of the following: LOLA_EDR, LOLA_RDR, LOLA_RADR, LOLA_GDR, LOLA_SHADR, and SLDEM2015. The EDR is the data produced by the instrument, in a form as close as possible to the files recorded on the spacecraft. The RDR data is calibrated, edited, and geolocated in a reversible manner. The RADR data are along-track profiles that contain normal albedo, the radiance of the Moon at zero phase angle. The GDR is a dataset resampled at uniform intervals, in both cylindrical and polar projections. The SHADR is a set of spherical harmonic coefficients describing the lunar shape, selenopotential reference surface, albedo, and static gravitational potential. SLDEM2015 is a gridded dataset in cylindrical projection between 60S and 60N for all longitudes, in which LOLA data are co-registered with Kaguya Terrain Camera data.

The LOLA_EDR, LOLA_RDR, and LOLA_RADR directories are subdivided into LRO_PP_NN, where PP refers to the first two letters of mission phase (CO = Commissioning, NO = Nominal, SM = Science Mission, ES = Extended Science Mission or Second Extended Science Mission), and NN refers to the current monthly orbital cycle, ending with Station Keeping Maneuvers. The RADR directories are initially subdivided by the laser that was firing at the time, laser1 or laser2.

Typical filepaths for the EDR product is

/DATA/LOLA_EDR/LRO_NO_NN/LOLAEDRYYDDDHHMM.DAT.

Likewise the LOLA_RDR directory is subdivided and a typical file path for the RDR product is

/DATA/LOLA_RDR/LRO_NO_NN/LOLARDR_YYDDDHHMM.DAT.

This schematic shows an example of the nesting of directories for an EDR volume for data acquired beginning November 20, 2009 through December 17, 2009, ending at the fourth stationkeeping maneuver.

<Volume Root>

DATA|

| LOLA_EDR

| LRO_NO_03

|<LOLAEDR09dddhhmm.DAT files>

...

This schematic shows an example of the nesting of directories for the RDR, RADR, GDR, SHADR, and SLDEM data. For the gridded data products, <filespecs> are pixels per degree in CYLINDRICAL and meters per pixel in POLAR. Tiles are denoted by latitude range followed by longitude range, i.e., LDEM_512_00N_45N_180_360.IMG, or LDEM_75N_120M.IMG. The FLOAT_IMG floating point format is additionally provided for additional precision where file sizes remain reasonable. The PA subdirectories under LOLA_GDR and LOLA_SHADR contain a shape map and spherical harmonic model of the Moon using the dynamically defined Principal Axis coordinate system for consistency with other lunar gravity spherical harmonic models, including that acquired by the GRAIL mission.

<Volume Root>

-------------------

DATA|

|LOLA_GDR

|POLAR

|FLOAT_IMG

|<LDEM_[<filespecs>]_FLOAT.IMG files>

|IMG

| <LDEM_[<filespecs>].IMG files>

|JP2

| <LDEM_[<filespecs>].JP2 files

|LOLA_GDR

|CYLINDRICAL

|FLOAT_IMG

|<LDEM_[<filespecs>]_FLOAT.IMG files>

|IMG

| <LDEM_[<filespecs>].IMG files>

|JP2

| <LDEM_[<filespecs>].JP2 files

|PA

| <LDEM_[<filespecs>]_PA.IMG files>

|LOLA_RDR

| LRO_NO_03

|<LOLARDR_yydddhhmm.DAT files>

|LOLA_RADR

|LASER1

|LRO_[mission phase]_[orbital cycle]

|LOLARADR_yydddhhmm.TAB

|POLARPATCH_[NP or SP]

|LRO_[mission_phase]_[orbital cycle]

|LOLARADR_yydddhhmm_[NP or SP].TAB

|LASER2

|LRO_[mission phase]_[orbital cycle]

|LOLARADR_yydddhhmm.TAB


|LOLA_SHADR

|LRO_LTM[model number]_[degree and order]_SHA.TAB

|PA

|LRO_LTM[model number]_PA_[degree and order]_SHA.TAB


|SLDEM2015

|GLOBAL

|FLOAT_IMG

|<SLDEM_[<filespecs_lat_lon>]_FLOAT.IMG files>

|JP2

| SLDEM_[<filespecs>].JP2 files

|TILES

|FLOAT_IMG

|<SLDEM_[<filespecs_lat_lon>]_FLOAT.IMG files>

|JP2

| SLDEM_[<filespecs>].JP2 files

Each data file is accompanied by a PDS label file with the same name. JP2 products additionally have an accompanying XML file for use with certain mapping software; see the file JP2INFO.TXT in the DOCUMENT directory.

2.3.INDEX Directory Contents

Files in the INDEX Directory are provided to help the user locate products on this archive volume and on previously released volumes in the archive. The following files are contained in the INDEX Directory.

Table 3. Description of files in INDEX Directory

File Name

File Contents

File Provided By

EDRINDEX.LBL

A PDS detached label that describes EDRINDEX.TAB

LOLA SOC

EDRINDEX.TAB

A table listing all EDR data products in the archive

LOLA SOC

EDRINDEX.LBL

A PDS detached label that describes EDRINDEX.TAB

LOLA SOC

EDRINDEX.TAB

A table listing all EDR data products in the archive

LOLA SOC

RDRINDEX.LBL

A PDS detached label that describes RDRINDEX.TAB

LOLA SOC

RDRINDEX.TAB

A table listing all RDR, RADR, GDR, SHADR, and SLDEM data products in the archive

LOLA SOC

INDXINFO.TXT

A description of the contents of this directory

LOLA SOC

2.4.DOCUMENT Directory Contents

The DOCUMENT Directory contains documentation to help the user understand and use the archive data. The following files are contained in the DOCUMENT Directory.

Table 4. Description of files in DOCUMENT Directory

File Name

File Contents

File Provided By

ARCHSIS.HTM

The Archive Volume SIS (this document) as hypertext

LOLA SOC

ARCHSIS.LBL

A PDS detached label that describes both ARCHSIS.HTM and ARCHSIS.PDF

LOLA SOC

ARCHSIS.PDF

The Archive Volume SIS (this document) as a PDF file

LOLA SOC

ARCHSIS_*.JPG

Images used in ARCHSIS.HTM

LOLA SOC

DOCINFO.TXT

A description of the contents of this directory

LOLA SOC

EDRSIS.HTM

The EDR Data Product SIS as hypertext

LOLA SOC

EDRSIS.LBL

A detached label that describes both EDRSIS.HTM and EDRSIS.PDF

LOLA SOC

EDRSIS.HTM

The EDR Data Product SIS as hypertext

LOLA SOC

EDRSIS.LBL

A detached label that describes both EDRSIS.HTM and EDRSIS.PDF

LOLA SOC

EDRSIS.PDF

The EDR Data Product SIS as a PDF file

LOLA SOC

EDRSIS_*.JPG

Images used in EDRSIS.HTM

LOLA SOC

JP2INFO.TXT

Description of JP2 versions of GDR images and how to use them

LOLA SOC

MISSION_PHASE_TIMES.TAB

Table of start and stop times for LRO orbital mission phases

LOLA SOC

RDRSIS.HTM

The RDR Data Product SIS as hypertext

LOLA SOC

JP2INFO.TXT

Description of JP2 versions of GDR images and how to use them

LOLA SOC

MISSION_PHASE_TIMES.TAB

Table of start and stop times for LRO orbital mission phases

LOLA SOC

RDRSIS.HTM

The RDR Data Product SIS as hypertext

LOLA SOC

RDRSIS.LBL

A detached label that describes both RDRSIS.HTM and RDRSIS.PDF

LOLA SOC

RDRSIS.PDF

The RDR Data Product SIS as a pdf file

LOLA SOC

RDRSIS_*.JPG

Images used in RDRSIS.HTM

LOLA SOC

SLDEM2015.TXT

Description of SLDEM data

LOLA SOC

2.5.CATALOG Directory Contents

The files in the CATALOG Directory provide a top-level understanding of the mission, spacecraft, instruments, and data sets. The files in this directory are coordinated with the PDS data engineer, who is responsible for loading them into the PDS catalog. The following files are found in the CATALOG Directory.

Table 5. Description of files in CATALOG Directory

File Name

File Contents

File Provided By

CATINFO.TXT

A description of the contents of this directory

LOLA SOC

DSMAP.CAT

Map projection information for simple cylindrical projection

LOLA SOC

DSMAP_POLAR.CAT

Map projection information for polar stereographic projection

LOLA SOC

EDR_DS.CAT

EDR data set information for the PDS catalog

LOLA SOC

EDR_VOLDESC.CAT

EDR (raw) altimetry volume catalog (also found in root directory of EDR archive volume)

LOLA SOC

GDR_DS.CAT

Gridded Data Record information for the PDS (including SLDEM2015)

LOLA SOC

INSTHOST.CAT

Instrument host (i.e., spacecraft) information for the PDS

LRO Project

LOLAINST.CAT

Instrument information for the PDS catalog

LOLA SOC

MISSION.CAT

Mission information for the PDS catalog

LRO Project

PERSON.CAT

Personnel information for the PDS catalog (Team and PDS personnel responsible for generating the archive)

LOLA SOC

RADR_DS.CAT

RADR dataset information for the PDS

LOLA SOC

RDR_DS.CAT

RDR dataset information for the PDS

LOLA SOC

RDR_VOLDESC.CAT

RDR, RADR, GDR, SLDEM, and SHADR Volume catalog (also found in root directory of RDR archive volume)

LOLA SOC

REF.CAT

References mentioned in other *.CAT files

LOLA SOC

SHADR_DS.CAT

Spherical Harmonic Data Record information for the PDS

LOLA SOC

2.6.LABEL Directory Contents

The LABEL Directory contains files that describe data format and organization. These files are referred to in the PDS labels that accompany the data products. They are "include" files that are intended to be parsed as if they were part of the PDS labels that refer to them. The following files are contained in the LABEL Directory.

Table 6. Description of files in LABEL Directory

File Name

File Contents

File Provided By

LABINFO.TXT

A description of the contents of this directory

LOLA SOC

LOLAEDR.FMT

LOLA science telemetry 1-Hz data format

LOLA SOC

LOLAHKCT.FMT

LOLA housekeeping telemetry container for 28 Hz data

LOLA SOC

LOLARADR.FMT

LOLA active radiometry data record format

LOLA SOC

LOLARDR.FMT

LOLA reduced science data record format for 28 Hz data

LOLA SOC

LOLASCCT.FMT

LOLA science telemetry container for 28 Hz data

LOLA SOC

2.7.CALIB Directory Contents

The CALIB Directory contains calibration files used to process the data products, or calibration data needed to use the data products. The following files are contained in the CALIB Directory.

Table 7. Description of files in CALIB Directory

File Name

File Contents

File Provided By

CALINFO.TXT

A description of the contents of this directory

LOLA SOC

CALIBRPT.LBL

A PDS detached label that describes both CALIBRPT.HTM and CALIBRPT.PDF

LOLA SOC

CALIBRPT.PDF

Description of instrument and data calibration performed by LOLA team

LOLA SOC

CALIBRPT.HTM

HTML version of instrument and data calibration

LOLA SOC

CALIBRPT_FILES

Directory of images used in CALIBRPT.HTM

LOLA SOC


2.8.GEOMETRY Directory Contents

The GEOMETRY Directory contains files needed to understand observation geometry. Geometry information incorporating refined analyses of the instrument and spacecraft geometry are produced in CK, SPK, and SCLK formats. The C-kernel (CK) system is the component of SPICE concerned with attitude of spacecraft structures or instruments. The SCLK system is the component of SPICE concerned with spacecraft clock correlation data. These are archived separately via the NAIF Node and can be referenced at http://naif.jpl.nasa.gov/pub/naif/pds/data/lro-l-spice-6-v1.0

The SPK system is the component of SPICE concerned with ephemeris data. The LOLA SPKs are precision orbits calculated using a GRAIL-based gravity field, and are archived as part of the Radio Science data archive. These can be found at http://pds-geosciences.wustl.edu/lro/lro-l-rss-1-tracking-v1/lrors_0001/data/spk

The boresight vector is used to geolocate returns measured by the instrument. The unit boresight vectors used for the initial LOLA release were revised (10/06/2010) by a few hundredths of a degree to reflect in-flight improvements in knowledge.

The most recent revision (6/16/2014) implements a separate set of boresight vectors for day and night to account for misalignment of the laser beam expander caused by the contraction of thermal blankets facing the cold night side of the Moon. The LOLA geometry assumes an offset of the laser vector origin (X, Y, Z) = (2.046, 0.961, 0.523) in meters with respect to the spacecraft frame. The precision orbits determine the spacecraft center of mass, relative to which the laser vector origin is (X, Y, Z) = (1.0, 1.14, 0.55) meters. The unit vector of the laser range relative to the SPICE frame LRO_SC (-85000) is given by the time-dependent data statements for each of the five beams. The values used for different data releases are given in this directory in the file BORESIGHT.TXT

Table 8. Description of files in GEOMETRY Directory

File Name

File Contents

File Provided By

GEOMINFO.TXT

A description of the contents of this directory

LOLA SOC

LRO_LOLA_V01.TI

Description of LOLA instrument frames used by SPICE

LOLA SOC

BORESIGHT.TXT

Boresight vector values used for geolocation

LOLA SOC


2.9.BROWSE Directory Contents

The BROWSE Directory contains reduced-size, easily viewed versions of data products to be used to help identify products of interest. The following files are contained in the BROWSE Directory.

Table 9. Description of files in BROWSE directory

File Name

File Contents

File Provided By

BROWINFO.TXT

A description of the contents of this directory

LOLA SOC

BROWINFO.HTM

HTML File linking browse images to products

LOLA SOC

BROWINFO.LBL

PDS label for BROWINFO.TXT and BROWINFO.HTM

LOLA SOC

LOLA_RDR

Directory containing images of topographic profiles organized by mission phases

LOLA SOC

LOLA_GDR

Directory containing images of gridded products

LOLA SOC

The browse information consists of images of profiles for the RDR data products, while that for the GDR products are thumbnail images of topographic shaded relief or ancillary data. Either PNG, GIF or JPEG formats are employed, with images linked to an HTML-based table.

2.10.EXTRAS Directory Contents

The EXTRAS Directory contains documentation, utility programs, or other materials that the user may find helpful, but that are beyond the scope of the required elements of the archive. There are no restrictions on the contents and organization of this directory other than conformance to ISO-9660/UDF standards. The EXTRAS Directory is intended for "value-added" material, handy to have but not crucial for understanding the data. The following files are contained in the EXTRAS Directory.

Table 10. Description of files in EXTRAS directory

File Name

File Contents

File Provided By

EXTRINFO.TXT

A description of the contents of this directory

LOLA SOC

INDEX.HTML

HTML File linking ancillary documentation and utilities

LOLA SOC

CELESTIA

LOLA data textures for use with Celestia 3D simulation software

LOLA SOC

FRACTAL

Maps of coefficients indicating lunar roughness

LOLA SOC

GEOID

Maps of lunar geoid height derived from LOLA data

LOLA SOC

ILLUMINATION

Maps of solar illumination, permanently shadowed regions, solid angle of the sky as visible from the lunar surface, and average visibility of the Earth from the lunar surface

LOLA SOC

SLDEM2015

A redundant version of the files under DATA, to be consistent with location given in published paper

LOLA SOC

SOFTWARE

Software for viewing or extracting data

LOLA SOC


3.Archive Volume Format

This section describes the format of LOLA Archive Volumes. Data that comprise the Archive is formatted in accordance with Planetary Data System specifications [Applicable Document 8].

3.1.File Formats

The following section describes file formats for the kinds of files contained on archive volumes. For more information, see the PDS Archive Preparation Guide §1.3.

3.1.1.Document File Format

Document files with the .CAT or .TXT suffix exist in the ROOT, INDEX, CATALOG, DOCUMENT, and LABEL directories. They are ASCII files that may have embedded PDS labels. Lines in such files end with a carriage return character (ASCII 13) and a line feed character (ASCII 10). This allows the files to be readable under various operating systems.

Documents in the DOCUMENT and CALIB directory may contain formatting and figures that cannot be rendered as ASCII text. Therefore each document is given in two formats, hypertext and PDF. The hypertext file contains ASCII text plus hypertext markup language (HTML) commands that enable it to be viewed in a Web browser such as Mozilla (the successor to Mosaic and Netscape), Safari (the browser for Mac OS X), or IE7 (the default browser for Microsoft Corporation products). The hypertext file may be accompanied by ancillary files such as images and style sheets that are incorporated into the document by the Web browser for the convenience of the user. The second format, PDF (Portable Document Format) is a proprietary format of Adobe Systems Incorporated that is frequently used for distributing documents. Adobe offers free software, Acrobat Reader, for viewing PDF files.

3.1.2.Tabular File Format

Tabular files (.TAB suffix) exist in the INDEX directory. They are ASCII files formatted for direct reading into many database management systems on various computers. All fields are separated by commas, and character fields are enclosed in double quotation marks ("). (Character fields are padded with spaces to keep quotation marks in the same columns of successive records.) Character fields are left justified, and numeric fields are right justified. The "start byte" and "bytes" values listed in the labels do not include the commas between fields or the quotation marks surrounding character fields. The records are of fixed length, and the last two bytes of each record contain the ASCII carriage return and line feed characters. This allows a table to be treated as a fixed length record file on computers that support this file type and as a text file with embedded line delimiters on those that don't.

All tabular files are described by PDS labels, either embedded at the beginning of the file or detached. If detached, the PDS label file has the same name as the data file it describes, with the extension .LBL; for example, the file EDRINDEX.TAB is accompanied by the detached label file EDRINDEX.LBL in the same directory.

3.1.3.PDS Label Format

All data files in the archive have PDS labels, either embedded at the beginning of the file or, in the case of the EDR data product, detached in a separate file. For examples of PDS labels for each type of data product, see the Data Product SISs [Applicable Documents 2 and 11].

A PDS label, whether embedded or detached from its associated file, consists of lines of ASCII text in the form of keyword = value statements that provide descriptive information about the data file. The label is intended to be readable both by humans and by software. Details of the syntax and semantics of PDS labels can be found in the PDS Standards Reference (Applicable Document 8), and definitions of the keywords used in the label can be found by using the PDS Data Dictionary Lookup web service at URL https://pds.nasa.gov/tools/dd-search/.

Lines of text in detached labels end with a carriage return character (ASCII 13) and a line feed character (ASCII 10). This allows the files to be read under various operating systems.

3.1.4.Catalog File Format

Catalog files (suffix .CAT) exist in the Root and CATALOG directories. Like PDS labels, they are text files formatted as “keyword = value statements”. They contain descriptions of the data set, instrument, spacecraft, and mission, as well as personnel contact information and references to published literature. They are called Catalog Files because they are loaded into the PDS online catalog to make the information available to users searching for data.

3.1.5.Science Data File Formats

The LOLA EDR data products are in the form of binary time-ordered tables representing engineering telemetry and laser time-of-flight data in counts. Each file corresponds to a single file downloaded from the spacecraft solid-state recorder. The binary tables include columns with multi-byte integers in both most-significant-byte-first and least-significant-byte-first order, as well as nonstandard triplets representing 24-bit integers. One file contains approximately 5 minutes of engineering and science data, including Earth ranges from the Laser Ranging experiment. Information about the format and content of the data products is given in the EDR Data Product SIS [Applicable Document 2].

The LOLA RDR data products are maintained in the form of binary time-ordered tables for ease of manipulation. All columns consist of 2-byte and 4-byte, signed or unsigned LSB integers that may be translated into ASCII tables for the end users by means of provided software in /EXTRAS/SOFTWARE. Each RDR product will be aggregated on orbital boundaries into a product name with extension “.DAT” and provided with a detached label with the same product name and an extension “.LBL”. The detached label will reference Format files contained in the archive's LABEL directory.

The LOLA RADR data products are maintained in the form of ascii time-ordered tables. The LOLARADR.FMT file, found in the LABEL directory, specifies the format for each field in the data product. A detached label with the same product name and an extension “.LBL” is provided alongside each file.

The primary LOLA GDR data products consists of raster Digital Elevation Models (shape models)and Digital Elevation Counts (samples per pixel) as binary images with detached labels. Additional GDR products include slope and roughness grids, albedo grids, and elevation maps derived from the cross-registration of LOLA and Kaguya data (SLDEM grids). The file type of the GDR products is “IMG”. The larger _FLOAT.IMG, in decimal format, is also provided for smaller grids. The JPEG2000 lossless compressed file format, with a file extension of “JP2”, are also employed using Geospatial Data Abstraction Library headers (www.gdal.org). This format provides smaller file sizes and is compatible with many Geographical Information Systems. The global JP2 files have a projection center longitude of 0 degrees, following GIS practice, as distinct from the 0-360 convention used for the IMG products, as recommended by the LRO Project.

A pixel in the GDR product represents the mean value at the center of a region bounded by lines of constant longitude and latitude at integral numbers of degrees or fractions thereof, scaled and interpolated where necessary. The size of the products at higher resolutions requires that they be aggregated in subsets of global coverage. Global standard products use the Equirectangular map projection, also known as Simple Cylindrical, while the higher-resolution products afforded by dense polar coverage use the Polar Stereographic projection. Tiling is employed to limit the size of individual products to less than 2 GB to facilitate electronic data transfer. Binary elevation data consists of 16-bit integers, scaled by 0.5 meters to a dynamic range of ±16 km relative to datum. The resolution of equirectangular pixels is in powers of two pixels per degree of longitude and latitude. The resolution of polar projected pixels is in integral numbers of meters at a radius of 1737400 m, true at the pole. The pole is a point surrounded by the four central pixels, and the colatitude of a pixel at a distance r meters from the north pole is simply 2 arctan (0.5 r /1737400). Anticipated tiles and product sizes are as follows, while tiling is shown in Figure 1.

Table 11. Equirectangular map-projected digital elevation models

Product

Product Size

Pixel size

Number/size of tiles

bits per pixel

LDEM_4

2 MB

7.5808 km in latitude

Global, 0-360

16

LDEM_16

32 MB

1.895 km in latitude

Global, 0-360

16

LDEM_64

512 MB

0.4738 km in latitude

Global, 0-360

16

LDEM_128

2 GB

0.2369 km in latitude

Global, 0-360

16

LDEM_256

4x2GB

118.45 m in latitude

4 tiles, longitudes 0:180:360 by N/S

16

LDEM_512

16x2GB

59.225 m in latitude

longitudes 0:90:180:270:360 by 45° latitude bands

16

LDEM_1024

* 64x2GB

29.612 m in latitude

longitudes 0:45:90:135:180:225:270:315:360 by 22.5° latitude bands

16

Note: Product size is limited to 2GB for compatibility with most platforms. Geospatial products may be generated in larger sizes as special products.

Figure 1: Equirectangular map projection. Lines show notional tiling subdivisions of LDEM_256 (bold), LDEM_512 (fine), and LDEM_1024 (dashed).


Polar stereographic projections are produced at latitudes from 45 degrees to the poles. These consist of a single image file at each pole, roughly 1.8 GB in size, as well as subsampled images, i.e. LDEM_75S_120M is 4x4 coarser than LDEM_75S_30M. Those products with * were not generated in earlier deliveries due to the lack of data density. They were generated at full resolution once data density permitted.

Table 12. Polar map-projected digital elevation models, N/S

Product

dimensions

Pixel size

Latitude range

bits per pixel

LDEM_45S_100M

28800x28800

100x100m

+/-45° to pole

16

*LDEM_60S_60M

31040x31040

60x60 m

+/-60° to pole

16

LDEM_75S_30M

30496x30496

30x30 m

+/-75° to pole

16

*LDEM_80S_20M

30400x30400

20x20 m

+/-80° to pole

16

LDEM_85S_10M

30336x30336

10x10 m

+/-85° to pole

16

*LDEM_87S_5M

30336x30336

5x5 m

+/-87.5° to pole

16

Figure 2: Polar stereographic map projection from 45°N to pole. Circles show outlines of LDEMs at various resolutions (innermost circles enclose 10 and 5 meter DEMs).


Special map products are also generated to describe surface properties such as albedo, slope, and roughness, in formats consisting of a subset of the DEM products. Algorithms for producing these products depend on performance of the instrument, research and development. Ancillary special map products will be generated to show data density or interpolation quality.

The LOLA SHADR data products consist of ASCII tables, preceded by PDS labels. The form of these tables will be that of Comma-Separated Values. The tables will closely resemble that of the Lunar Prospector gravity archives. Spherical harmonic shape and bidirectional reflectance models will complete the SHADR dataset. The gravity potential coefficients are customarily normalized so that the spherical harmonic functions each have unit mean variance on a sphere, in accordance with geophysical practice, and are further normalized to a reference equatorial radius of 1,738,000 meters. This choice of radius is for compatibility with legacy datasets, and with observation equations - “normal equations” - used in orbital and potential analysis that, for compact storage, are summed with respect to a particular radius. The derived potential coefficients may be transformed to any other choice of reference radius.

4.Archive Volume Generation

4.1.Data Transfer and Validation Methods

All LOLA products and labels are generated by the Lunar Orbiter Laser Altimeter Science Team at GSFC. The LOLA Team validates the products for scientific integrity in conjunction with other LRO instrument teams. The EDR products are checked for transmission errors and correctness of associated labels. The RDR products undergo editing steps and pipeline processing, with subsequent analysis to validate their measurement accuracy. The RDR products undergo monthly revisions after each orbit maintenance cycle. Standard methods are used to create the GDR and SHADR products, whose revisions are associated with that of the cumulative RDR dataset. The entire archive is hosted at the LOLA SOC as a Data Node of the PDS, per Applicable Document #6. According to the schedule set by the LRO Project, the LOLA Team makes a delivery of completed archive volumes to PDS every three months, beginning six months after the start of the mapping mission. The Geosciences Node validates sample EDR and RDR products and completed archive volumes for compliance with PDS standards. Delivery to PDS is performed in accordance with Applicable Document #6.

4.2.Data Product Sizes and Delivery Rates

Table 2 summarizes expected sizes and production rates for the LOLA EDR and RDR Standard Products, as well as estimates of the higher level product volumes.

Table 13. Standard Product Sizes and Delivery Rates


Product

Product Size

Production Rate

Expected Number of Products for Nominal Mission

Expected Total Data Volume for Nominal Mission

LOLA_EDR

23-24 MB

12.1-12.4 per day, average

4700

113 GB

LOLA_RDR

~50 MB

same

4700

235 GB

LOLA_GDR

<2 GB

monthly revisions of ~100 data products

100

200 GB

LOLA SHADR

5 MB

release at quarterly intervals

4

<1 GB


4.3.Interface Media Characteristics

All removable volumes in the LOLA Standard Product Archive, whether CD, DVD-ROM, or electronic archive, conform to ISO 9660 standards [ISO 9660, 1988].

4.4.Backup and Duplicates

Backup copies of LOLA EDR, RDR, RADR, SLDEM, GDR, and SHADR products will be stored at the LOLA Data Node at GSFC and at the Department of Earth, Atmospheric, and Planetary Sciences of the Massachusetts Institute of Technology until the final versions of products have been archived on physical media with the PDS. Duplicate copies of LOLA archive volumes will be stored on physical media at the PDS Geosciences Node and the National Space Science Data Center.

4.5.Labeling and Identification

There are two LOLA archive volumes. They will be identified by a unique VOLUME_ID formed according to the scheme LROLOL_dXXX where:

LRO is the mission ID

LOL is the instrument ID

d is the data set stored on the archive volume, where

d = 0 for EDR only;

d = 1 for RDR, RADR, GDR, SHADR, SLDEM, and special products.

Should it become necessary to rerelease the archives, the VOLUME_ID will be incremented. XXX represents an online volume of unlimited size. In the event that the PDS ever repackages the archive on smaller media units such as DVDs, the XXX is replaced by a volume sequence number starting with 001.

5.Support Staff and Cognizant Persons

David E. Smith, LOLA Principal Investigator, NASA Goddard Space Flight Center

Maria T. Zuber, LOLA Deputy P.I., Massachusetts Institute of Technology

Gregory A. Neumann, LOLA co-Investigator, NASA Goddard Space Flight Center

Mark H. Torrence, LOLA Science Operations Manager, NASA Goddard Space Flight Center

Kopal Jha, LOLA Support Scientist, NASA Goddard Space Flight Center

Susan Slavney, PDS Geosciences Node, Washington University, St. Louis, Missouri

Jennifer G. Ward, Mission Archivist, PDS Geosciences Node, Washington University, St. Louis, Missouri

6.Appendices

6.1.Contents of the RDRINDEX.LBL file

PDS_VERSION_ID = PDS3

RECORD_TYPE = FIXED_LENGTH

RECORD_BYTES = 293

FILE_RECORDS = 4637

^INDEX_TABLE = "RDRINDEX.TAB"

VOLUME_ID = LROLOL_1XXX

DATA_SET_ID = "LRO-L-LOLA-3-RDR-V1.0"

MISSION_NAME = "LUNAR RECONNAISSANCE ORBITER"

INSTRUMENT_NAME = "LUNAR ORBITER LASER ALTIMETER"

DESCRIPTION = "This index file lists information

about each of the LRO LOLA RDR data products contained on

this archive volume."


OBJECT = INDEX_TABLE

INDEX_TYPE = SINGLE

INTERCHANGE_FORMAT = ASCII

ROWS = 4637

ROW_BYTES = 293

COLUMNS = 13

DESCRIPTION = "

This table contains the volume index of all data files on

this volume.


Each record of this index consists of comma delimited data

columns followed by an ASCII carriage-return and line-feed.

The ROW_BYTES value includes not only the lengths of

the values themselves, but also any quotes, the commas, and

the row terminating characters (carriage-return,line-feed).

The BYTES value in each column definition includes only the

value, not surrounding quotation marks or commas."


OBJECT = COLUMN

NAME = VOLUME_ID

COLUMN_NUMBER = 1

START_BYTE = 2

BYTES = 12

DATA_TYPE = CHARACTER

DESCRIPTION = "The PDS VOLUME_ID: LROLOL_1XXX"

END_OBJECT = COLUMN


OBJECT = COLUMN

NAME = FILE_SPECIFICATION_NAME

COLUMN_NUMBER = 2

START_BYTE = 17

BYTES = 57

DATA_TYPE = CHARACTER

DESCRIPTION = "Fully qualified name of the data file, relative to

the volume root directory"

END_OBJECT = COLUMN

/* Note that the file specification originates at the root, so no */

/* logical volume path name is included. */


OBJECT = COLUMN

NAME = MISSION_PHASE_NAME

COLUMN_NUMBER = 3

START_BYTE = 77

BYTES = 30

DATA_TYPE = CHARACTER

DESCRIPTION = "The mission phase during which the observations

were obtained."

END_OBJECT = COLUMN


OBJECT = COLUMN

NAME = TARGET_NAME

COLUMN_NUMBER = 4

START_BYTE = 110

BYTES = 12

DATA_TYPE = CHARACTER

DESCRIPTION = "The target observed."

END_OBJECT = COLUMN


OBJECT = COLUMN

NAME = PRODUCT_ID

COLUMN_NUMBER = 5

START_BYTE = 125

BYTES = 24

DATA_TYPE = CHARACTER

DESCRIPTION = "PRODUCT_ID from the PDS label"

END_OBJECT = COLUMN


OBJECT = COLUMN

NAME = PRODUCT_VERSION_ID

COLUMN_NUMBER = 6

START_BYTE = 152

BYTES = 5

DATA_TYPE = CHARACTER

DESCRIPTION = "PRODUCT_VERSION_ID from the PDS label"

END_OBJECT = COLUMN


OBJECT = COLUMN

NAME = PRODUCT_CREATION_TIME

COLUMN_NUMBER = 7

START_BYTE = 159

BYTES = 19

DATA_TYPE = TIME

DESCRIPTION = "Creation time from the PDS label"

END_OBJECT = COLUMN


OBJECT = COLUMN

NAME = DATA_SET_ID

COLUMN_NUMBER = 8

START_BYTE = 180

BYTES = 23

DATA_TYPE = CHARACTER

DESCRIPTION = "DATA_SET_ID from the PDS label."

END_OBJECT = COLUMN


OBJECT = COLUMN

NAME = STANDARD_DATA_PRODUCT_ID

COLUMN_NUMBER = 9

START_BYTE = 206

BYTES = 9

DATA_TYPE = CHARACTER

DESCRIPTION = "STANDARD_DATA_PRODUCT_ID from the PDS label.

Identifies the data product in the volume archive."

END_OBJECT = COLUMN


OBJECT = COLUMN

NAME = START_TIME

COLUMN_NUMBER = 10

START_BYTE = 217

BYTES = 23

DATA_TYPE = TIME

DESCRIPTION = "The UTC START_TIME value from the PDS label"

END_OBJECT = COLUMN


OBJECT = COLUMN

NAME = STOP_TIME

COLUMN_NUMBER = 11

START_BYTE = 241

BYTES = 23

DATA_TYPE = TIME

DESCRIPTION = "The UTC STOP_TIME value from the PDS label"

END_OBJECT = COLUMN


OBJECT = COLUMN

NAME = SPACECRAFT_CLOCK_START_COUNT

COLUMN_NUMBER = 12

START_BYTE = 265

BYTES = 13

DATA_TYPE = ASCII_INTEGER

DESCRIPTION = "The SPACECRAFT_CLOCK_START_COUNT value from the PDS

label. This is the MET of the beginning of the observation."

END_OBJECT = COLUMN


OBJECT = COLUMN

NAME = SPACECRAFT_CLOCK_STOP_COUNT

COLUMN_NUMBER = 13

START_BYTE = 279

BYTES = 13

DATA_TYPE = ASCII_INTEGER

DESCRIPTION = "The SPACECRAFT_CLOCK_STOP_COUNT value from the PDS

label. This is the MET of the end of the observation."

END_OBJECT = COLUMN


END_OBJECT = INDEX_TABLE

END