PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM SPACECRAFT_NAME = "CLEMENTINE 1" TARGET_NAME = MOON OBJECT = DATA_SET DATA_SET_ID = "CLEM1-L-U-5-DIM-BASEMAP-V.10" OBJECT = DATA_SET_INFORMATION DATA_SET_NAME = "CLEMENTINE BASEMAP MOSAIC" DATA_SET_COLLECTION_MEMBER_FLG = "N" START_TIME = 1994-01-25 STOP_TIME = 1994-05-07 DATA_SET_RELEASE_DATE = 1996-03-01 PRODUCER_FULL_NAME = "DR. ALFRED S MCEWEN" DETAILED_CATALOG_FLAG = "N" DATA_OBJECT_TYPE = "IMAGE" DATA_SET_DESC = " Data Set Overview ================= The Clementine Basemap Mosaic is a full-resolution (100 meters per pixel) global mosaic produced by the U.S. Geological Survey from Clementine EDR Data. The 750 nanometer filter imaging data acquired by the Ultraviolet/Visible Camera were used to create the single-band basemap mosaic. The Clementine Basemap Mosaic is partitioned on the CD collection in the Sinusoidal Equal-Area Projection as 12 'zones', each 30 degrees wide in longitude and ranging from 70 degrees south latitude to 70 degrees north latitude. All tiles in a zone have the same center longitude of projection. Both polar regions between 70 degrees to 90 degrees latitude exist both as Sinusoidal and polar stereographic projections. Each zone and each polar region exist on one CD-ROM volume. This results in a 14-volume archive set containing the full resolution (0.1 km/pixel) mosaic. A fifteenth volume, containing reduced-resolution planetwide coverage at .5, 2.5, and 12.5 km/pixel and other ancillary data, complete the archive collection. For each full- and reduced- resolution image product, a sub-sampled 'browse' image is provided in Joint Photographic Experts Group (JPEG) format. Each 30 degree zone is further divided into smaller tiles. The tiling scheme, basic to digital cartography design, is similar to previous planetary global mosaics, and maintains reasonably sized image products. In general, this design consists of rectangular tiles that are roughly 2100 pixels on a side. The actual tile size varies with latitude. Near the equator, each tile covers 7 degrees of latitude and 6 degrees of longitude. A typical full-resolution tile required ~9 megabytes of digital storage and may contain approximately 35 raw Clementine images. Parameters ========== N/A Processing ========== The Integrated Software for Imaging Spectrometers (ISIS) processing system, developed by the U.S. Geological Survey was used to generate the basemap mosaic. Processing within ISIS includes radiometric and geometric correction, spectral registration, photometric normalization, and image mosaicking. Radiometric correction applies 'flat fielding', dark current subtraction, non-linearity correction, and conversion to radiometric units. Geometric transformations tie each raw image with a ground control network and convert from raw image coordinates to the Sinusoidal Equal-Area projection. Photometric normalization is applied to balance brightness variations due to illumination differences among the images in a mosaic. Images are then mosaicked together to form a global map of continuous image coverage for the entire planet. Media/Format ============ The Clementine basemap is delivered to the Planetary Data System using CD media. Formats are based on standards for such products established by the Planetary Data System (PDS) [PDSSR1992]. " CONFIDENCE_LEVEL_NOTE = " Overview ======== The Clementine Basemap Mosaic is the result of an exhaustive Lunar cartography project based on data from the Clementine EDR image collection. Systematic calibration and processing enable global, full-resolution scientific analysis of the Clementine Datasets. A first major step in the systematic processing of the imaging data is the production of an accurate basemap to which all products are geometrically registered. Previous maps and ground control points of he Moon is not sufficiently accurate The previous RAND control network is accurate to 500 meters in the area covered by the Apollo mapping frames (15% of the Moon's surface), and is accurate to about 1-2 kilometers for regions covered by telescopic, Galileo, and Mariner 10 observations. However, most of the far side is not included in the network, and the only other positional dataset for these regions contains errors as large as tens of kilometers. Based on best effort measurements of the spacecraft orbit and pointing, UVVIS geometric distortions, and time tags for each observation, the SPICE data alone provides positional accuracies better than 1 kilometer over most of the Moon. With residuals primarily small random pointing errors, then accuracies approaching the UVVIS scale becomes achievable. The goal of the basemap is for 99% of the Moon (excluding the oblique observation gap fills) to be 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. To achieve these goals we required camera alignment and pointing data accurate to a few hundredths of a degree. We determined the absolute alignment of the UVVIS with respect to spacecraft-fixed axes (A and B Star Tracker Camera quaternions) by analyzing a major subset of the over 17,000 images of Vega, over 6,000 images of the Southern Cross and a few hundred images of the Pleiades, taken during the approach to the Moon and throughout the lunar mapping mission phase. Multiple star images within a single picture were used to determine the UVVIS focal length and optical distortion parameter values. Approximately 265,000 match points were collected at the USGS from ~43,000 UVVIS images providing global coverage. About 80% of these points were collected via autonomous procedures, whereas the 20% required the more time consuming but highly accurate pattern-recognition capability of the human eye-brain. We also developed streamlined procedures for the supervised collection of match points. The new procedures saved several person-years of effort and represents new capabilities useful with other planetary datasets. The automated success rate exceeded 90% along each spacecraft orbit track, where the overlap regions of successive images are highly correlated, but failed when the overlap regions is narrow and/or nearly featureless. ('Failure' is defined as less than 3 points per image with correlation coefficients grater than 0.85; thus, many good match points were rejected because we could not be certain that the matches were valid without verification.) Across-track matching was more difficult due to changes in scale and illumination angle, but a fair success rate (~60%) was nevertheless achieved via the use of 'window-shaping' (local geometric reprojections). The 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 overlaps 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 UVVIS images. A constant lunar radius of 1737.4 kilometers was assumed, 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 triangulation was first computed on 'packets' of match points (each covering ~1/8-th of the Moon), then checked and rechecked at the USGS via plots and test mosaics to fix and add match points as needed. 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 will be tied." END_OBJECT = DATA_SET_INFORMATION OBJECT = DATA_SET_TARGET TARGET_NAME = MOON END_OBJECT = DATA_SET_TARGET OBJECT = DATA_SET_HOST INSTRUMENT_HOST_ID = CLEM1 INSTRUMENT_ID = UVVIS END_OBJECT = DATA_SET_HOST OBJECT = DATA_SET_REFERENCE_INFORMATION REFERENCE_KEY_ID = "PDSSR1992" END_OBJECT = DATA_SET_REFERENCE_INFORMATION END_OBJECT = DATA_SET END