THE CLEMENTINE HIRES MOSAIC CONTENTS 1 - INTRODUCTION 2 - CLEMENTINE MISSION 3 - HIGH RESOLUTION CAMERA (HiRes) 4 - LUNAR ORBIT SUMMARY 5 - GEOMETRIC REGISTRATION 6 - RADIOMETRIC ISSUES 7 - DATA PROCESSING 8 - FILE, DIRECTORIES AND DISK CONTENTS 9 - IMAGE FILE ORGAINZATION 10 - INDEX FILES 11 - REFERENCES APPENDIX A - KEYWORD ASSIGNMENT INTRODUCTION ============ This compact disk (CD) is one of 20 which comprise mosaics of the Clementine I high resolution (HiRes) camera images of the moon. These mosaics were produced through semi-automated registration and calibration against the recently released geometrically and photometrically controlled Ultraviolet/Visible (UV/Vis) Basemap Mosaic. The HiRes mosaics were compiled from non-uniformity corrected, 750 nanometer ("D") filter high resolution nadir-looking observations from the HiRes imaging system onboard the Clementine Spacecraft. The images were spatially warped using the sinusoidal equal-area projection at a scale of 20 m/pixel. To avoid the necessity of iterative reprojection, which was beyond the scope of the present effort, only images with emission angles less than approximately 5 degrees were used. Similarly, images from non-mapping cross-track slews, which tended to have large SPICE errors, were generally omitted. The locations of the resulting image population were offset from the UV/Vis basemap by up to 13 km (0.4 deg). The geometric control was provided by the 100 m/pixel U. S. Geological Survey (USGS) Clementine Basemap Mosaic compiled from the 750 nm Ultraviolet/Visible Clementine imaging system. Calibration was achieved by removing the image nonuniformity dominated by the HiRes system's light intensifier. Also provided are offset and scale factors, achieved by a fit of the HiRes data to the corresponding photometrically calibrated UV/Vis basemap, that approximately transform the 8-bit HiRes data to photometric units. The mosaics are divided into tiles that cover approximately 1.75 degrees of latitude and span the longitude range of the mosaicked frames. Images from a given orbit are map projected using the orbit's nominal central latitude. This CD also contains ancillary data files that support the HiRes mosaic. These files include browse images with UV/Vis context stored in a Joint Photographic Experts Group (JPEG) format, index files ('imgindx.tab' and 'srcindx.tab') that tabulate the contents of the CD, and documentation files. For more information on the contents and organization of the CD volume set refer to the "FILES, DIRECTORIES AND DISK CONTENTS" section of this document. The Clementine HiRes Mosaic was compiled for the National Aeronautics and Space Administration (NASA) by Malin Space Science Systems personnel under the direction of Dr. Michael C. Malin, principal Investigator. Jeff Warren and Rick Adair comprised the technical group responsible for its compilation. Much of the background text in this document draws heavily on McEwen et al. [1997]. CLEMENTINE MISSION =================== The Clementine Mission [Nozette et al., 1994] was a technology demonstration jointly sponsored by the Ballistic Missile Defense Organization (BMDO) and the National Aeronautics and Space Administration (NASA). Clementine was launched on 1994-01-25 aboard a Titan IIG rocket from Vandenburg Air Force Base. The mission included two months of systematic lunar mapping (1994-02-26 through 1994-04-21), which was to have been followed by a flyby of the near-Earth asteroid Geographos (1994-08-31). However, an onboard software error combined with improbable hardware conditions on 1994-05-07 led to accidental spin-up of the spacecraft and loss of attitude control gas. This precluded the flyby of Geographos. Clementine's primary objective was the qualification of light weight imaging sensors and component technologies for the next generation of Department of Defense spacecraft. A second objective was the return of data about the Moon and Geographos to the international civilian scientific community. For more information on the Clementine Mission refer to the 'mission.cat' file located in the 'catalog' directory. The HiRes mosaic was created using the Clementine EDR Image Archive [Eliason, et al., 1995] produced by the Clementine mission. The EDR (Engineering Data Record) data are raw images. The archive also includes tabulations of the unprocessed and uncorrected data properties. The Clementine EDR Image Archive contains more than 1.9 million images acquired during active mission operations. For information on how to obtain this archive contact the PDS Imaging Node or visit their world wide web site at the URL: http://pdsimage.jpl.nasa.gov/PDS. HIGH RESOLUTION (HiRes) IMAGING CAMERA ====================================== The HiRes camera combined a lightweight beryllium telescope with an image intensifier-coupled frame transfer CCD imager. Image shuttering was accomplished through voltage gating of the image intensifier. Maximum integration time was 733 milliseconds in 10.67 microsecond increments. The spectral response was limited in the system by the S-2 photocathode between 0.4 and 0.8 microns. Five spectral bands were available using a filter wheel that was controlled through the serial-addressable synchronous interface (SASI). A sixth filter position was allocated to an opaque filter for the imager intensifier's protection. Additional information on the HiRes camera is in the 'hresinst.cat' file in the 'catalog' directory. The post-FPA electronic circuitry was identical to that used in the UV/Vis camera: three gains states were allowed, followed by 5 bits of offset that span 248 counts in the analog regime to augment the basic 8-bit A/D conversion. Images of the Moon's day side used relatively low gain settings and intensifier gate times on the order of 1 ms. Lifetime concerns about the photocathode and microchannel plates in the intensifier unit drove operations settings to low exposures. This resulted in photon shot noise contributing significantly to the overall noise in the HiRes sensor. Further, the image intensifier imposed a non-uniform, but predictable, artifact within the images. LUNAR ORBIT SUMMARY =================== The Clementine spacecraft maintained a polar orbit during the systematic mapping of the surface of the Moon. Mapping of virtually 100% of the lunar surface was accomplished in two lunar days (two Earth months). In order to obtain full coverage during these two months, the required image overlap for the UV/Vis and NIR cameras was ~15% in the down-track and ~10% in the cross-track directions. This required an orbit inclination of 90 degrees plus-or- minus 1 degree with reference to the lunar equator, and that the periselene of the orbit be maintained at an altitude of 425 plus-or-minus 25 km. To provide the necessary cross-track separation for the alternating imaging strips to cover the entire surface of the moon, the orbital period was approximately 5 hours, during which the moon rotated approximately 2.7 degrees beneath the spacecraft. Images were generally taken and recorded only in the region of periselene, leaving sufficient time to replay the data to Earth. The best data for lunar mineral mapping is obtained if the solar phase angle is less than 30 degrees. The solar phase angle is defined as the angle between the vector to the Sun and the vector to the spacecraft from a point on the Moon's surface. To maximize the time period in which the solar phase angle is less than 30 degrees, the plane of the orbit should contain the Moon-Sun line half way through the two-month lunar mapping period. Therefore, insertion into orbit was selected so that, as the Moon-Sun line changed with Earth's motion about the Sun, the Moon-Sun line was initially close on the orbital plane, and then in the orbital plane half-way through the mapping mission. The angle between the Moon-Sun line and the orbital plane was close (less than 5 degrees) for approximately five weeks before becoming zero. The table shown below contains a list of Clementine's orbital parameters. For more information on the Lunar orbit refer to the 'mission.cat' file located in the 'catalog' directory. Clementine Orbital Parameters =========================================================== Orbital Period: 4.970 hr < P < 5.003 hr Altitude of Periselene: 401 km < radius < 451 km Eccentricity: 0.35821 < e < 0.37567 Right Ascension: -3 deg < Omega < +3 deg (referred J2000) Inclination: 89 deg < i < 91 deg Argument of Periselene: -28.4 deg < w < -27.9 deg (1st month) 29.6 deg < w < 29.2 deg (2nd month) GEOMETRIC ACCURACY ================== The geometric placement of the HiRes mosaics is based primarily on registration with the Clementine Basemap Mosaic, which has accuracies approaching the UV/Vis scale. Thus, an overview of Basemap Mosaic is appropriate. The UV/Vis Basemap Mosaic ------------------------- The goal of the UV/Vis basemap was for 95% of the Moon (excluding the oblique observation gap fills) to have better than 0.5 km/pixel absolute positional accuracy and to adjust the camera angles so that all frames match neighboring frames to within an accuracy of 2 pixels. Approximately 265,000 match points were collected at the USGS from ~43,000 UV/Vis images, providing global coverage. About 80% of these points were collected via autonomous procedures, whereas 20% required the more time consuming but highly accurate manual pattern-recognition. Oblique gap-fill images were the most difficult to match, and required substantial human intervention. Matching the polar regions was time-consuming because each frame overlapped many other frames. Most match points were found to a precision of 0.2 pixels. The USGS match points were sent to RAND Corporation for analytical triangulations. Using these match points, control points from the Apollo region, and the latest NAIF/SPICE information, RAND determined improved camera orientation angles for the global set of UV/Vis images. A spherical Moon of constant radius (1737.4 kilometers) was assumed, which was a significant source of error near the oblique gap fills. The analytical triangulation is a least-squares formulation designed to adjust the latitude and longitude of the control points and the camera orientation angles to best fit the match points. The final (global) analytical triangulation required solving ~660,000 normal equations. The mean error is less than 1 pixel. This is by far the largest analytical triangulation ever applied to a planetary body other than Earth. The results fully define the planimetric geometry of the basemap, to which future systematic products, including the HiRes mosaic, should be tied. The HiRes Mosaic ---------------- Accurate placement of the map-projected HiRes images was accomplished by combining registration to the UV/Vis basemap at the basemap's resolution (100 m/pixel) with registration of overlapping HiRes pairs at five times this resolution (20 m/pixel). The registrations were facilitated with automated image correlation. These registrations were combined in a Least Absolute Deviation fit (Barrodale and Roberts, 1980) constrained to stray no further than some small amount from the basemap-scale registration. Use of the least absolute deviation gives outliers less importance than does a least squares fit. Further manual placement of 1-5 percent of the images was required; these were due either to poor initial placement, particularly when the scene was featureless and provided few or no overlapping features with the UV/Vis basemap, or to mismatches of scene, resolution or illumination across seams in the UV/Vis mosaic. Some misregistration of adjacent HiRes images remains in the final mosaic because the paramount goal was registration with the underlying UV/Vis Basemap Mosaic. RADIOMETRIC UNITS ================= To date, absolute photometric calibration of the HiRes image data remains elusive. This seems particularly problematic for the bulk of HiRes images, which were noisy due to the low gain setting intended to extend the life of the imaging system. For this product, piece-wise intensity matching of the HiRes mosaics to the UV/Vis Basemap Mosaic was adopted as an approximate radiometric calibration. The further decision was made to use 750 nm ("D") filter HiRes images in order to best match the UV/Vis Basemap Mosaic, which dominantly comprises 750 nm ("B") filter images. A more detailed description of the UV/Vis basemap photometric calibration may be found on the UV/Vis basemap volumes CL_30XX. Since the photometric level of the underlying UV/Vis basemap was observed to be approximately constant over the 1.75-degrees latitude bins of each HiRes mosaic tile, a single linear scaling of the HiRes tiles provides an approximate photometric calibration to an accuracy commensurate with the quality of the HiRes images. Thus, following mosaicking, the DN values of reduced-resolution 1.75-degree HiRes mosaic tiles were least-squares fit to the corresponding UV/Vis basemap values to estimate this linear scaling. The result is a scale and offset applied to the 8-bit HiRes DN in exactly the same manner as the UV/Vis scale and offset to provide approximate HiRes fractional reflectances. In each tile header, then, the OFFSET and SCALING_FACTOR entries define HiRes fractional reflectances for that tile and that tile only: HIRES MOSAIC FRACTIONAL_REFLECTANCE = (SCALING_FACTOR * DN) + OFFSET where: DN = 8-bit pixel value of HiRes mosaic image array. SCALING_FACTOR units are fractional reflectance per DN OFFSET units are fractional reflectance The calibration in every case included correction for the non-uniformity of the raw HiRes images due to the light intensifier (Robinson, personal communication, 1997). DATA PROCESSING =============== Image processing tools developed at Malin Space Science Systems were used for image map projection, registration, tone matching and mosaicking. MapMaker was used to generate context images from the UV/Vis Basemap Mosaic. Processing proceeded on an orbit and latitude "bin" basis, reflecting the organization of the Clementine EDR CDs. A latitude bin consists of all images of a given orbit deemed to fall within a 10 degree latitude range based on SPICE information. The latitude ranges are defined to fall on 10-degree boundaries from -90 to +90. Map projection of images from a given orbit used the same central longitude, taken to be the orbit's longitude at the lunar equator. The HiRes mosaic was processed in 5 steps: 1. image calibration, map project, and basemap generation 2. lores registration 3. HiRes registration 4. constrained registration 5. mosaic and estimate photometric calibration Step 1 ------- Following calibration for image non-uniformity, each image is warped with the sinusoidal equal-area projection [Snyder, 1982], using the SPICE information in the EDR's PDS header. Only "D" filter (750 nm) images are considered. Images with no apparent content, indicated by MINIMUM = MAXIMUM (DN) header entries, or low intensifier gains (< 10) are rejected. Also rejected are images with excessive emission angles. The HiRes SPICE information is erroneous to some degree, necessitating further effort to register them with the UV/Vis Basemap Mosaic. Both high resolution (20 m/pixel) and low-resolution (100 m/pixel) versions are generated. For this purpose, an appropriate UV/Vis context is generated, reprojecting as needed to match the central longitude of a given orbit's images. Step 2 ------ Step 2 registers the HiRes images at UV/Vis basemap resolution. The HiRes images generally have some small systematic deviation away from a geometrically controlled position. This deviation is of order 10-200 pixels at 100 m/pixel, tending to be largest near the poles. Correlation of the HiRes images to the UV/Vis basemap permits estimation of HiRes image offsets relative to the UV/Vis basemap. Provisional image placements that failed the correlation effort are estimated from neighboring "good" images that did not fail. Very rarely, "holes" in the underlying basemap, due to absence of valid UV/Vis data, result in stretches of HiRes data which lack geometric constraint to the basemap. Step 3 ------ Overlapping "good" images are correlated against each other to provide a "full-resolution" placement constraint. Step 4 ------ The results of the reduced and full resolution registrations are combined to define a constrained, least absolute-deviation problem for the image placement. Like the more familiar least-squares fit procedure, this seeks to minimize deviation away from specified targets, in this case the nominal absolute and relative HiRes image placements. However, least-squares tends to weight outlying locations in a manner considered undesirable. An additional constraint is imposed by not allowing the any placement solution to stray further than 3 UV/Vis-resolution pixels from the nominal location. Occasionally, this constraint must be relaxed to accommodate relatively severe UV/Vis mosaic seam offsets. Step 5 ------ Using the estimated placements, the full resolution HiRes images are provisionally mosaicked, laying frames down from south to north. This provisional mosaic is manually examined to detect misplaced and invalid (no significant content) images, due in some cases to an image taken while gain states were transitioning to different values. Misplaced images are manually mosaicked, and invalid images flagged for exclusion. Because the UV/Vis Basemap Mosaic is the de facto control network for lunar cartography, HiRes images are permitted to mismatch each other when forced by UV/Vis scene content which is mismatched across mosaic seams. Following the manual quality review, a final mosaic is produced as tiles that span 2 degrees of latitude. Low resolution versions with UV/Vis context are also generated to estimate an approximate photometric calibration. This calibration is computed as the least-squares linear fit of the 1.75-degree tile's DN values to those of the underlying UV/Vis basemap, an 8-bit version generated from the 16-bit versions provided on CD. This chain of linear scalings is then combined to provide a nominal scaling of the tile DNs to physical photometric (fractional reflectance) values. FILES, DIRECTORIES, AND DISK CONTENTS ===================================== The files on CD volume set are organized starting at the root or 'parent' directory. Below the parent directory is a directory tree containing data, documentation, and index files. In the table below directory names are indicated by brackets (<...>), upper-case letters indicate an actual directory or file name, and lower-case letters indicate the general form of a set of directory or file names. 4. CD CONTENTS, DIRECTORY, AND FILENAMING CONVENTION The files on this CD are organized starting at the root or 'parent' directory. Below the parent directory is a directory tree containing data, documentation, and index files. In the table below directory names are indicated by brackets (<...>), upper-case letters indicate an actual directory or file name, and lower-case letters indicate the general form of a set of directory or file names. DIRECTORY/FILE CONTENTS ------------------- ------------------------------------------ <root> | |-INDEX.HTM Starting point for web-browsing CD contents. | |-AAREADME.TXT The file you are reading (ASCII Text). | |-ERRATA.TXT Description of known anomalies and errors | present on the volume set(optional file). | |-VOLDESC.CAT A description of the contents of this | CD volume in a format readable by | both humans and computers. | |-<CATALOG> Catalog Directory | | | |-CATINFO.TXT Describes Contents of the Catalog directory | | | |-DATASET.CAT Clementine HiRes Mosaic description. | | | |-DSMAP.CAT Map Projection description. | | | |-INSTHOST.CAT Clementine Spacecraft description. | | | |-MISSION.CAT Clementine Mission description. | | | |-PERSON.CAT Contributors to Clementine HiRes mosaic. | | | |-REFS.CAT References for Clementine HiRes mosaic. | | | |-HRESINST.CAT HiRes Camera description. | |-<DOCUMENT> Documentation Directory. The files in this | | directory provide detailed information | | regarding the Clementine HiRes Mosaic. | | | |-DOCINFO.TXT Description of files in the DOCUMENT | | directory. | | | |-VOLINFO.TXT Documentation regarding the | | contents of this CD Volume Set. | | | |-VOLINFO.HTM Documentation regarding the | | contents of this CD Volume Set in HTML format. | | | |-VOLINFO.LBL PDS Label file describing the VOLINFO | | documents. | |-<INDEX> Directory for the image index files. | | | |-INDXINFO.TXT Description of files in <INDEX> directory. | | | |-IMGINDX.TAB Image Index table. | | | |-IMGINDX.LBL PDS label for IMGINDX.TAB. | | | |-SRCINDX.TAB Table of source images used in the | | production of the Clementine HiRes mosaic. | | | |-SRCINDX.LBL PDS Label for SRCINDX.TAB | | |-<tile directory> Data directory names indicating center longitude of each orbit | | number encoded as floor(longitude*10), and has form HXXXmmmm, | | where mmmm is defined below. | | | |-<Hnnemmmm.IMG> Strip mosaic data product in PDS format. Filename | | is coded as follows: | | | | nn = two digit center latitude (i.e. INT(lat)). | | e = N (North Latitude) | | S (South Latitude) | | mmmm = projection center longitude * 10 | | | |-<BROWSE> Subdirectory containing browse images for HTML interface. | | | | | |-<Hnnemmmm.JPG> Browse image in JPEG format with UV/Vis context for | | | corresponding PDS image. | | | | | |-<Hnnemmmm.HTM> Browse HTML file for for corresponding PDS image. IMAGE FILE ORGANIZATION ======================= The image files are stored in a PDS compliant format. An image file contains an label area (header) at the beginning of the file followed by the image data. The number of bytes of the label area is a multiple of the number of bytes that make up an image line (number of samples * 1 bytes/pixel). The image label area contains ASCII text data that contains information about the image file (see Image Labels section below). The label area can be viewed with a simple ASCII editor on most computer systems. Pixel Representation -------------------- The Clementine HiRes mosaic is stored as image files with 8-bit unsigned integer pixels. Image Labels ------------ The label area of a image file contains descriptive information about the image. The label consists of keyword statements that conform to version 3 of the Object Description Language (ODL) developed by NASA's PDS project. There are three types of ODL statements within a label: structural statements, keyword assignment statements, and pointer statements. Structural statements provide a shell around keyword assignment statements to delineate which data object the assignment statements are describing. The structural statements are: 1) OBJECT = object_name 2) END_OBJECT 3) END The OBJECT statement begins the description of a particular data object and the END_OBJECT statement signals the end of the object's description. All keyword assignment statements between an OBJECT and its corresponding END_OBJECT statement describe the particular object named in the OBJECT statement. The END statement terminates a label. A keyword assignment statement contains the name of an attribute and the value of that attribute. Keyword assignment statements are described in more detail in Appendix B of this document. These statements have the following format: name = value Values of keyword assignment statements can be numeric values, literals, and text strings. Pointer statements are a special class of keyword assignment statements. These pointers are expressed in the ODL using the following notation: ^object_name = location If the object is in the same file as the label, the location of the object is given as an integer representing the starting record number of the object, measured from the beginning of the file. The first label record in a file is record 1. Pointers are useful for describing the location of individual components of a data object. Pointer statements are also used for pointing to data or label information stored in separate files. An example of a detached label (i.e., label information stored in a separate file) is shown below: By convention, detached labels are found in the LABEL directory. ^STRUCTURE = 'logical_file_name' The value of 'logical_file_name' is the name of the detached label file containing the description. The keyword statements in the label are packed into the fixed-length records that make up the keyword label area. Each keyword statement is terminated by a carriage-return and line-feed character sequence. An example of a Clementine HiRes strip mosaic image label is shown below. Descriptions of the keywords used in the mosaic label are found in Appendix A. Example PDS Label for Clementine HiRes Strip Mosaic =================================================== PDS_VERSION_ID = PDS3 /* FILE FORMAT AND LENGTH */ RECORD_TYPE = FIXED_LENGTH RECORD_BYTES = 158 FILE_RECORDS = 2677 LABEL_RECORDS = 24 INTERCHANGE_FORMAT = BINARY /* POINTERS TO START RECORDS OF OBJECTS IN FILE */ ^IMAGE = 25 /* IMAGE DESCRIPTION */ DATA_SET_ID = "CLEM1-L-H-5-DIM-HIRES-V1.0" PRODUCT_ID = "H49S0378" PRODUCER_INSTITUTION_NAME = "MALIN SPACE SCIENCE SYSTEMS" PRODUCT_TYPE = MDIM MISSION_NAME = "DEEP SPACE PROGRAM SCIENCE EXPERIMENT" SPACECRAFT_NAME = "CLEMENTINE 1" INSTRUMENT_NAME = "HIGH RESOLUTION CAMERA" INSTRUMENT_ID = "HIRES" TARGET_NAME = "MOON" FILTER_NAME = "D" CENTER_FILTER_WAVELENGTH = 750.0000 BANDWIDTH = 50.0000 START_TIME = "N/A" STOP_TIME = "N/A" SPACECRAFT_CLOCK_START_COUNT = "N/A" SPACECRAFT_CLOCK_STOP_COUNT = "N/A" PRODUCT_CREATION_TIME = 1998-09-02T00:00:00 NOTE = "LUNAR HIRES MOSAIC" /* DESCRIPTION OF OBJECTS CONTAINED IN FILE */ OBJECT = IMAGE BANDS = 1 BAND_STORAGE_TYPE = BAND_SEQUENTIAL BAND_NAME = "N/A" LINES = 2653 LINE_SAMPLES = 158 SAMPLE_TYPE = UNSIGNED_INTEGER SAMPLE_BITS = 8 SAMPLE_BIT_MASK = 2#11111111# OFFSET = 1.78846745E-01 SCALING_FACTOR = 5.01661140E-04 VALID_MINIMUM = 1 NULL = 0 LOW_REPR_SATURATION = 0 LOW_INSTR_SATURATION = 0 HIGH_INSTR_SATURATION = 255 HIGH_REPR_SATURATION = 255 MINIMUM = 0 MAXIMUM = 125 CHECKSUM = 17038302 END_OBJECT = IMAGE OBJECT = IMAGE_MAP_PROJECTION ^DATA_SET_MAP_PROJECTION = "DSMAP.CAT" COORDINATE_SYSTEM_TYPE = "BODY-FIXED ROTATING" COORDINATE_SYSTEM_NAME = "PLANETOGRAPHIC" MAP_PROJECTION_TYPE = "SINUSOIDAL" MAP_RESOLUTION = 1516.1666667 MAP_SCALE = 0.0200000 MAXIMUM_LATITUDE = -49.0002199 MINIMUM_LATITUDE = -50.7493679 EASTERNMOST_LONGITUDE = 37.1729801 WESTERNMOST_LONGITUDE = 37.0093190 LINE_PROJECTION_OFFSET = -74290.5000000 SAMPLE_PROJECTION_OFFSET = 760.5000000 A_AXIS_RADIUS = 1737.4000000 B_AXIS_RADIUS = 1737.4000000 C_AXIS_RADIUS = 1737.4000000 FIRST_STANDARD_PARALLEL = "N/A" SECOND_STANDARD_PARALLEL = "N/A" POSITIVE_LONGITUDE_DIRECTION = EAST CENTER_LATITUDE = 0.0 CENTER_LONGITUDE = 37.8000000 REFERENCE_LATITUDE = "N/A" REFERENCE_LONGITUDE = "N/A" LINE_FIRST_PIXEL = 1 SAMPLE_FIRST_PIXEL = 1 LINE_LAST_PIXEL = 2653 SAMPLE_LAST_PIXEL = 158 MAP_PROJECTION_ROTATION = 0.0000000 VERTICAL_FRAMELET_OFFSET = "N/A" HORIZONTAL_FRAMELET_OFFSET = "N/A" END_OBJECT = IMAGE_MAP_PROJECTION END INDEX FILES =========== Each CD volume in the Clementine HiRes mosaic contains an image index file ('imgindx.tab') with catalog information about the entire basemap. The image index file and it's associated PDS label file ('imgindx.lbl') are located in the 'index' directory. The catalog information in the index table includes the file names, CD volumes, and mapping parameter information. An additional source file index table ('srcindx.tab' and corresponding PDS label 'srcindx.lbl')contains information about the EDR image collection used to assemble the basemap. This file contains an entry for each EDR image that was used in the mosaic. For more information on the contents of the index files refer to the label files. REFERENCES ========== Acton, C.H., Ancillary Data Services of NASA's Navigation and Ancillary Information Facility: Planetary and Space Sciences, Vol. 44, No. 1, pp. 65-70, 1996. Barrodale, I. and Roberts, F.D.K., Algorithm 552: Solution of the Constrained L1 Linear Approximation Problem, ACM TOMS 6 (2), 231-235, 1980 Batson, R.M., Digital Cartography of the Planets: New Methods, its status, and its Future: Photogrammetric Engineering and Remote Sensing, Vol. 53, No. 9, p. 1211-1281. Batson, R.M., 1990, Cartography: in Greeley, Ronald, and Batson, eds. Planetary Mapping: New York, Cambridge University Press, pp. 60-95. Eliason, E.M., E.R. Malaret, and G. Woodward, Clementine Mission, The Archive of Image Data Products and Data Processing Capabilities (Abstract): Proceedings of the 26-th Lunar and Planetary Conference, pp. 369-370, 1995. McEwen, A., E.M.Eliason, C. Isbell, E. Lee, T. Becker, M. Robinson (1997). The Clementine Basemap Mosaic. volinfo.txt, CLEM1-L-U-5-DIM-BASEMAP-V1.0. JPL, PDS Standards Reference: JPL Document D-7669, JPL , Pasadena, California, 1992. Kordas, J.R., I.T. Lewis, R.E. Priest, W.T. White, D.P. Nielsen, H. Park, B.A. Wilson, M.J. Shannon, A.G. Ledebuhr, and L.D. Pleasance, UV/visible Camera for the Clementine Mission: Proceedings of the Society of Photo-optical Instrumentation Engineers (SPIE), 2478, pp. 175-186, 1995. Nozette, S., P. Rustan, L.P. Pleasance, D.M. Horan, P. Regeon, E.M. Shoemaker, P.D. Spudis, C.H. Acton, D.N. Baker, J.E. Blamont, B.J. Buratti, M.P. Corson, M.E. Davies, T.C. Duxbury, E.M. Eliason, B.M. Jakosky, J.F. Kordas, I.T. Lewis, C.L. Lichtenberg, P.G. Lucey, E. Malaret, M.A. Massie, J.H. Resnick, C.J. Rollins, H.S. Park, A.S. McEwen, R.E. Priest, C.M. Pieters, R.A. Reisse, M.S. Robinson, D.E. Smith, T.C. Sorenson, R.W. Vorder Breugge, and M.T. Zuber; The Clementine Mission to the Moon: Scientific Overview: Science, 266, 1835-1839, 1994. Snyder, J.P, Map Projections Used by the U.S. Geological Survey: Geological Survey Bulletin 1532, U.S. Government Printing Office, Washington D.C., 313 pp., 1982. APPENDIX A - KEYWORD ASSIGNMENTS ================================ This section defines the keywords used in the image label area of the Clementine basemap mosaic. PDS_VERSION_ID = PDS3 This dataset conforms to version 3 of the PDS standards. RECORD_TYPE = FIXED_LENGTH This keyword defines the record structure of the file as fixed- length record files. RECORD_BYTES = xxxx Record length in bytes for fixed-length records (number of samples) FILE_RECORDS = xxxx Total number of fixed-length records contained in the file LABEL_RECORDS = x Number of fixed-length label records in the file INTERCHANGE_FORMAT = BINARY Data are organized as BINARY values ^IMAGE = x Pointer to the first record that contains image data. (The first record in the file is designated as record 1.) DATA_SET_ID = "CLH-002" The PDS defined data set identifier for the Clementine HiRes mosaic PRODUCT_ID = "xxxxx" Unique product identifier for this image file. This value is the same as the file name. (Format described in the "FILES, DIRECTORIES, AND DISK CONTENTS" section above.) PRODUCER_INSTITUTION_NAME = "MALIN SPACE SCIENCE SYSTEMS" Identifies the producer organization of this data product. PRODUCT_TYPE = MDIM This keyword identifies the image product as a Mosaicked Digital Image Model (MDIM). MISSION_NAME = "DEEP SPACE PROGRAM SCIENCE EXPERIMENT" The keyword identifies the product name of the mission. (This is the official name of the Clementine Mission.) SPACECRAFT_NAME = "CLEMENTINE 1" Name of the spacecraft that acquired the data. INSTRUMENT_NAME = "HIGH RESOLUTION CAMERA" Name of the instrument that acquired the image data. INSTRUMENT_ID = "HiRes" Abbreviated name of the instrument that acquired the image data. TARGET_NAME = "MOON" Target of the data product. FILTER_NAME = "D" Designation of the 750 nm HiRes filter, chosen because virtually all images that make up the Clementine Basemap Mosaic were acquired using the filter "B", also a 750 nm filter. (Filter "C" (900 nm) UV/Vis images were used when filter "B" data were not available.) CENTER_FILTER_WAVELENGTH = 750.0000 The center filter wavelength of filter "D" is 750 nanometers. BANDWIDTH = 50.0000 The bandwidth of the filter "D" is 50 nanometers. START_TIME = "N/A" STOP_TIME = "N/A" SPACECRAFT_CLOCK_START_COUNT = "N/A" SPACECRAFT_CLOCK_STOP_COUNT = "N/A" Start_Time, Stop_Time, and clock counts are not applicable (N/A) for this data product but are required keywords. PRODUCT_CREATION_TIME = 1998-06-16T00:00:00 Time at which the image product was produced. NOTE = "LUNAR HiRes MOSAIC" Note field always says LUNAR HiRes MOSAIC. OBJECT = IMAGE BANDS = 1 There is only one spectral band in the HiRes mosaic. BAND_STORAGE_TYPE = BAND_SEQUENTIAL Storage order is band sequential BAND_NAME = "N/A" Band name keyword is not applicable. LINES = xxxx Number of lines (rows) in image array LINE_SAMPLES = xxxx Number of samples (columns) in image array. SAMPLE_TYPE = UNSIGNED_INTEGER Data are stored as unsigned, two's complement integers. SAMPLE_BITS = 8 There are 8 bits per sample (1 byte) SAMPLE_BIT_MASK = 2#11111111# This keyword indicates all bits within a 8-bit byte are used in the expression of the value. OFFSET = xxxxx SCALING_FACTOR = xxxxx The OFFSET and SCALING_FACTOR keywords contain values used to convert the 8-bit integer pixel value to radiometric units. FRACTIONAL_REFLECTANCE = (PIXEL* SCALING_FACTOR) + OFFSET VALID_MINIMUM = 1 Lowest valid value that can be stored in pixel (always 1). NULL = 0 Value of empty pixels or missing data (always 0). LOW_REPR_SATURATION = 0 Value of pixel if processing caused a low-end value pixel to go outside dynamic range of a 8-bit unsigned integer (always 0). LOW_INSTR_SATURATION = 0 Value if pixel was low-end saturated (always 0). For example, if the bias of the camera was set so that low DN values could not be stored in the pixel. HIGH_INSTR_SATURATION = 255 Value of pixel if processing caused a high-end value pixel to go outside dynamic range of a 8-bit unsigned integer (always 255). HIGH_REPR_SATURATION = 255 Value if pixel was high-end saturated (always 255). For example, if the scene was too bright for the image to record at the pixel value became saturated. MINIMUM = xxxx Minimum value in image array. MAXIMUM = xxxx Maximum value in image array. CHECKSUM = xxxxxxxx Sum of all bytes in the image object. Used to validate that an image file was properly stored on the media. END_OBJECT = IMAGE OBJECT = IMAGE_MAP_PROJECTION ^DATA_SET_MAP_PROJECTION = "DSMAP.CAT" Name of file containing additional information about the map projection. DSMAP.CAT is located in the 'catalog' directory. COORDINATE_SYSTEM_TYPE = "BODY-FIXED ROTATING" COORDINATE_SYSTEM_NAME = "PLANETOGRAPHIC" Coordinate system used in the map projection. MAP_PROJECTION_TYPE = "SINUSOIDAL" Name of map projection. MAP_RESOLUTION = xxx.xxxxx Map resolution (pixels per degree) at the reference point of the projection. MAP_SCALE = x.xxxxxx Map scale (kilometers per pixel) at the reference point of the projection. MAXIMUM_LATITUDE = xx.xxxxxxx Maximum latitude of the image file MINIMUM_LATITUDE = xx.xxxxxxx Minimum latitude of the image file. EASTERNMOST_LONGITUDE = xxx.xxxxxxx Easternmost longitude of the image file. WESTERNMOST_LONGITUDE = xxx.xxxxxxx Westernmost longitude of the image file LINE_PROJECTION_OFFSET = xxxxx.xxxxxxx SAMPLE_PROJECTION_OFFSET = xxxxx.xxxxxxx Projection offsets are used to define the relationship between line and sample of the image array and the latitude and longitude coordinate on the surface of the planet. See 'dsmap.cat' file located in the 'catalog' directory for information on these keywords. A_AXIS_RADIUS = 1737.4000000 B_AXIS_RADIUS = 1737.4000000 C_AXIS_RADIUS = 1737.4000000 Three axis radius of the Moon used in the derivation of the map products that make up the basemap mosaic. FIRST_STANDARD_PARALLEL = "N/A" SECOND_STANDARD_PARALLEL = "N/A" Standard parallels of map, not used in this sinusoidal equal-area projection. POSITIVE_LONGITUDE_DIRECTION = EAST The Moon coordinate system uses a positive longitude direction of east. Longitude values increase in the eastern direction. CENTER_LATITUDE = 0.0 Center latitude of the map projection. CENTER_LONGITUDE = xxxx.xxxx Center longitude of the map projection. REFERENCE_LATITUDE = "N/A" REFERENCE_LONGITUDE = "N/A" Reference latitude and longitudes are not used in the sinusoidal equal-area projection. LINE_FIRST_PIXEL = 1 SAMPLE_FIRST_PIXEL = 1 The first pixel (upper left) in the image array is defined as line 1, sample 1. LINE_LAST_PIXEL = xxxx SAMPLE_LAST_PIXEL = xxxx The last pixel (lower right) in the image arrays is defined by these keywords. MAP_PROJECTION_ROTATION = 0.0000000 Map projection rotation always 0 for the Clementine Basemap Mosaic. VERTICAL_FRAMELET_OFFSET = "N/A" HORIZONTAL_FRAMELET_OFFSET = "N/A" These keywords are not applicable for the sinusoidal equal-area projection. END_OBJECT = IMAGE_MAP_PROJECTION END