OBJECT = DATASET DATA_SET_ID = 'MGN-V-RDRS-5-BIDR-FULL-RES-V1.0' OBJECT = DATASETINFO DATA_SET_NAME = 'MGN V RDRS DERIVED BASIC IMAGE DATA RECORD FULL RES V1.0' DATA_SET_COLLECTION_MEMBER_FLG = 'N' EVENT_START_TIME = 1990-09-16 EVENT_STOP_TIME = 1994-01-12 NATIVE_START_TIME = 'N/A' NATIVE_STOP_TIME = 'N/A' DATA_OBJECT_TYPE = 'IMAGE' DATA_SET_RELEASE_DATE = 'UNK' PROCESSING_LEVEL_ID = 5 PRODUCER_FULL_NAME = 'N/A' PRODUCER_INSTITUTION_NAME = "Multimission SAR Processing Facility, Jet Propulsion Lab" SOFTWARE_FLAG = 'N' DETAILED_CATALOG_FLAG = 'N' PROCESSING_START_TIME = 1990-09-16 PROCESSING_STOP_TIME = 'UNK' DATA_SET_DESC = "Full resolution basic image data records (F-BIDR) consist of SAR image data acquired along one orbit. Pixel widths are 75m. Data are presented as 8 bit pixel brightness values where the brightness is in proportion to the radar scaled backscatter cross section. Scaling is accomplished by dividing the specific cross section value (i.e. cross section/area) for each pixel by the value estimated from the Muhleman Law for the relevant incidence angle, converting the ratio to decibels, and scaling to a 1 to 251 output range. The 1 value corresponds to -20 dB and 251 to +30 dB, with a linear quantization of 0.2 dB in between. Data have at least 4 looks. Specifically, the scaled radar backscatter cross section is generated by: 1. Dividing the radar cross section / pixel area by the Muhleman Law. Muhleman Law is sigma naught = 0.0118 cos(i) / ((sin(i) + 0.111 cos(i))**3) where i = incidence angle. (Note: A value of 0.0188 was intended for the multiplicative constant, but 0.0118 was used by mistake. Also, the incidence angles used to compute the Muhleman Law are systematically low by 0.5 degrees.) 2. Converting to dB by taking 10 times log base 10 of the ratio generated in the first step. 3. Scaling output to a byte DN value using the expression: DN = 1 + INT ({MIN [MAX(RV,-20), 30] + 20} * 5) where RV = value produced in step 2, and INT = nearest integer function. F-BIDRs are presented as image files containing two integers at the beginning of each line. The first integer specifies the pixel offset to the first valid pixel; the second specifies the pixel offset to the last valid pixel. The remainder of the line consists of scaled backscatter cross section values. Regions within 89 degrees of the equator have F-BIDRs in sinusoidal equal area projection; F-BIDR data located more than 80 degrees of the equator are also in oblique sinusoidal equal area projections. For the sinusoidal equal area projection, the origin is at 0 degrees latitude and the central meridian is the sub-spacecraft longitude at the equator, adjusted to the nearest multiple of 75m, relative to a pixel centered at 0 degrees longitude. For details of use of the oblique sinusoidal equal area projection see Magellan Software Interface Specification (SIS) Document by John Gilbert, Full Resolution Basic Image Data Record, SDPS-101, October 1990. The first mapping cycle F-BIDRs extend from the north pole to approximately 60 degrees south latitude for northern strips and from just below the north pole to about 70 degrees south latitude for intervening F-BIDR strips. Images sizes are approximately 350 samples by 220,000 lines. Each F-BIDR file is located, together with a number of other, ancillary files, on one 6250 BPI 2400 foot 9 track tape. Each F-BIDR consists of approximately 106 million bytes of image data and 39 million bytes of ancillary data. Included in the ancillary files are processing parameters, orbital information, and radar operational information. Each F-BIDR tape contains 19 separate files." CONFIDENCE_LEVEL_NOTE = "Unknown" END_OBJECT = DATASETINFO OBJECT = DATASETTARG TARGET_NAME = 'VENUS' END_OBJECT = DATASETTARG OBJECT = DSPARMINFO SAMPLING_PARAMETER_NAME = 'PIXEL' SAMPLING_PARAMETER_RESOLUTION = 0.150 MINIMUM_SAMPLING_PARAMETER = 'N/A' MAXIMUM_SAMPLING_PARAMETER = 'N/A' SAMPLING_PARAMETER_INTERVAL = 0.075 MINIMUM_AVAILABLE_SAMPLING_INT = 'N/A' SAMPLING_PARAMETER_UNIT = 'KILOMETER' DATA_SET_PARAMETER_NAME = 'RADAR SCALED BACKSCATTER CROSS SECTION' NOISE_LEVEL = 'UNK' DATA_SET_PARAMETER_UNIT = 'DIMENSIONLESS' END_OBJECT = DSPARMINFO OBJECT = SCDSHOST INSTRUMENT_HOST_ID = 'MGN' INSTRUMENT_ID = 'RDRS' END_OBJECT = SCDSHOST OBJECT = DSREFINFO REFERENCE_KEY_ID = 'SAUNDERSETAL1990' END_OBJECT = DSREFINFO OBJECT = DSREFINFO REFERENCE_KEY_ID = 'GILBERT1990' OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = 'SOFTWARE INTERFACE SPECIFICATION' JOURNAL_NAME = 'N/A' PUBLICATION_DATE = 1990 REFERENCE_DESC = "Gilbert, John, Full Resolution Basic Image Data Record, Project Magellan Software Interface Specification Document SDPS-101, Jet Propulsion Laboratory, Pasadena, Calif., 1990." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = 'JOHN GILBERT' END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO END_OBJECT = DATASET END