PDS_VERSION_ID            = PDS3
RECORD_TYPE               = FIXED_LENGTH
FILE_RECORDS              = 259200
RECORD_BYTES              = 58
^TABLE                    = "IEG050_A.TAB"

DATA_SET_ID               = "MGS-M-MOLA-5-IEGDR-L3-V1.0"
PRODUCT_ID                = "MOLA-IEG050_A.TAB"
SPACECRAFT_NAME           = MARS_GLOBAL_SURVEYOR
INSTRUMENT_ID             = MOLA
INSTRUMENT_NAME           = MARS_ORBITER_LASER_ALTIMETER
TARGET_NAME               = MARS
START_TIME                = 1997-09-15T19:10:00.000
STOP_TIME                 = 1999-08-31T23:59:59.999
START_ORBIT_NUMBER        = 3
STOP_ORBIT_NUMBER         = 12153
PRODUCT_CREATION_TIME     = 2000-03-03T12:02:00.000
PRODUCER_ID               = MGS_MOLA_TEAM
PRODUCER_FULL_NAME        = "DAVID E. SMITH"
PRODUCER_INSTITUTION_NAME = "GODDARD SPACE FLIGHT CENTER"
DESCRIPTION               = "This data set is a topographic
   map of Mars at a resolution of 0.5 by 0.5 degrees, based on 
   altimetry data acquired by the Mars Global Surveyor MOLA 
   instrument and accumulated over the course of the mission so far. 
   The MOLA Precision Experiment Data Records (PEDRs) are the source
   for this data set. The map is in the form of an ASCII table with 
   one row for each 0.5 by 0.5 degree latitude-longitude bin, from 90 to 
   -90 degrees latitude and from 0 to 360 degrees longitude. The binned 
   data include all MOLA nadir observations from the Orbit Insertion
   phase, plus Mapping Phase nadir observations from the beginning of
   mapping through the end of August 1999. Additionally, off-nadir 
   observations of the north pole are included from 87 N latitude and 
   northward, taken during the spring of 1998, and of both poles taken
   in July of 1999, from 87 N and S to the poles.  Orbits 355 and 358 of 
   the Orbit Insertion Phase and parts of orbits 10709 through 10716, 
   inclusive, of the Mapping Phase are excluded because solutions for 
   these orbits are deemed to be poor. (Note: subtract 10000 from a MOLA 
   mapping phase orbit number to determine the equivalent MGS Project 
   orbit number.) Also excluded are shots more than 1 degree off-nadir 
   (except as noted above), channel 4 returns, and any returns not 
   classified as ground returns, e.g. clouds or noise, according to the 
   SHOT_CLASSIFICATION_CODE. A total of approximately 123 million 
   observations are represented."

OBJECT                    = TABLE
 INTERCHANGE_FORMAT       = ASCII
 ROWS                     = 259200
 ROW_BYTES                = 58
 COLUMNS                  = 6

 OBJECT                   = COLUMN
  NAME                    = AREOCENTRIC_LONGITUDE
  DATA_TYPE               = REAL
  START_BYTE              = 1
  BYTES                   = 8
  FORMAT                  = "F8.2"
  UNIT                    = DEGREE
  MINIMUM                 = 0.25
  MAXIMUM                 = 359.75
  DESCRIPTION             = "Areocentric east longitude of the center
    of the 0.5 by 0.5 degree area of observation. The rows in the table
    are in order by increasing longitude (0.25 to 359.75) and
    decreasing latitude (89.75 to -89.75), with longitude varying
    first."
 END_OBJECT               = COLUMN

 OBJECT                   = COLUMN
  NAME                    = AREOCENTRIC_LATITUDE
  DATA_TYPE               = REAL
  START_BYTE              = 9
  BYTES                   = 8
  FORMAT                  = "F8.2"
  UNIT                    = DEGREE
  MINIMUM                 = -89.75
  MAXIMUM                 = 89.75
  DESCRIPTION             = "Areocentric latitude of the center of
    the 0.5 by 0.5 degree area of observation. The rows in the table
    are in order by increasing longitude (0.25 to 359.75) and
    decreasing latitude (89.75 to -89.75), with longitude varying
    first."
 END_OBJECT               = COLUMN

 OBJECT                   = COLUMN
  NAME                    = MEAN_PLANETARY_RADIUS
  DATA_TYPE               = REAL
  START_BYTE              = 17
  BYTES                   = 12
  FORMAT                  = "F12.2"
  UNIT                    = METER
  MINIMUM                 = 3373300
  MAXIMUM                 = 3417028
  DESCRIPTION             = "Mean observed planetary radius within 
    the 0.5 by 0.5 degree area. Where no observations lie within the 
    area, an interpolated value is supplied. The mean of the observations
    is provided as an areodetically useful average, while the median is
    used for topography."
 END_OBJECT               = COLUMN

 OBJECT                   = COLUMN
  NAME                    = AREOID_RADIUS
  DATA_TYPE               = REAL
  START_BYTE              = 29
  BYTES                   = 12
  FORMAT                  = "F12.2"
  UNIT                    = METER
  MINIMUM                 = 3378182
  MAXIMUM                 = 3397477
  DESCRIPTION             = "Areoid radius at the center of the 0.5 by 0.5
    degree area of observation. The areoid radius lies on an 
    equipotential surface whose mean radius at the equator is 3396000 
    meters. The surface is defined by the Goddard Mars Potential 
    Model MGM0964C20, evaluated to degree and order 50."
 END_OBJECT               = COLUMN

 OBJECT                   = COLUMN
  NAME                    = MEDIAN_TOPOGRAPHY
  DATA_TYPE               = REAL
  START_BYTE              = 41
  BYTES                   = 10
  FORMAT                  = "F10.2"
  UNIT                    = METER
  MINIMUM                 = -7626.81
  MAXIMUM                 = 21017.03
  DESCRIPTION             = "Median observed topography within the 0.5
    by 0.5 degree area.  Where no observations lie within the area, 
    an interpolated value is supplied. The minimum and maximum topography 
    observations within the current data set are -7626.81 and 21017.03.
    Topography is the planetary radius minus the areoid radius at a
    longitude and latitude. The areoid radius at the center of the area 
    is not, in general, the same as the mean of the areoid radii at the 
    individual observations. Moreover, the median observed topography 
    follows sharp transitions in height more rapidly than the mean. Thus, 
    the median topography added to the areoid radius is not exactly equal
    to the mean planetary radius."
 END_OBJECT               = COLUMN

 OBJECT                   = COLUMN
  NAME                    = OBSERVATIONS
  DATA_TYPE               = INTEGER
  START_BYTE              = 51
  BYTES                   = 6
  FORMAT                  = "I6"
  MINIMUM                 = 0
  MAXIMUM                 = 1501
  DESCRIPTION             = "Number of observations in the 0.5 by 0.5 degree 
    area."
 END_OBJECT               = COLUMN

END_OBJECT                = TABLE

END