Magellan SAR Mosaic Image Data Record (MIDR) Description

Extracted from the PDS Data Set Catalog File.

  Data Set Description 
  ==================== 

    This dataset is derived from the Magellan Mosaic Image Data Record (MIDR)
    dataset produced by the Magellan project and distributed originally on CD-
    ROM in the 1990s. The original dataset had each mosaic divided into 56
    1024x1024 pixel framelets that were compatible with display technology
    available at the time. The original dataset were migrated to the PDS4
    standard. In the process of migration the individual framelets were
    reconstructed into a single image and new PDS labels for the reconstructed
    mosaic were created. There are four types of MIDRs: Full Resolution (F-
    MIDRs); Compressed one time (C1-MIDRs); Compressed two times (C2-MIDRs); and
    Compressed three times (C3-MIDRs).
    
    Full resolution Mosaic Image Data Records (F-MIDR) consist of SAR mosaics
    generated from F-BIDRs (i.e., with 75 meters/pixel). Each F-MIDR is in a
    sinusoidal equal area projection and has an origin at 0 degrees latitude,
    with the central meridian defined as the longitude bisecting the mosaic.
    Each F-MIDR has 7168 lines (aligned with latitude) by 8192 samples. F-
    MIDRs, with 75m pixl widths, have been generated for key terrains on the
    planet, regions where highest spatial resolution is required for analysis.
    
    Compressed Once Mosaic Image Data Records (C1-MIDRs) consist of mosaics
    generated from compressed basic image data records (C-BIDRs). C-BIDRs
    have been generated by computing 3x3 pixel arithmetic moving averages
    from the F-BIDRs. Each C1-MIDR is in a sinusoidal equal area projection
    and has an origin at 0 degrees latitude, with the central meridian
    defined as the longitude bisecting the mosaic. Each C1-MIDR has 7168
    lines (aligned with latitudes) and 8192 samples. C1-MIDRs, with their
    225m pixel widths, are designed to cover the planet at reasonably high
    resolution and high signal to noise ratio.
    
    Compressed Twice Mosaicked Image Data Records (C2-MIDRs) consist of
    mosaics generated by computing 3x3 pixel arithmetic moving averages from
    the C1-MIDRs. Each C2-MIDR is in a sinusoidal equal area projection and
    has an origin at 0 degrees latitude, with the central meridian defined as
    the longitude bisecting the mosaic. Each C2-MIDR has 7168 lines (aligned
    with latitudes) and 8192 samples. C2-MIDRs, with their 675 m pixel
    widths, are designed to cover the planet at reasonably high resolution
    and high signal to noise ratio.
    
    Compressed Thrice Mosaicked Image Data Records (C3-MIDRs) consist of
    mosaics generated by computing 3x3 pixel arithmetic moving averages from
    the C2-MIDRs. Each C3-MIDR is in a sinusoidal equal area projection and
    has an origin at 0 degrees latitude, with the central meridian defined as
    the longitude bisecting the mosaic. Each C3-MIDR has 7168 lines (aligned
    with latitudes) and 8192 samples. C3-MIDRs, with their 2.025 km pixel
    widths, are designed to cover the planet at reasonably high resolution
    and high signal to noise ratio. One C3-MIDR mosaicframe covers 137.5
    degrees in latitude and 157 degrees in longitude, at the equator.
                                                                              
    Please refer to the F-BIDR and C-BIDR dataset description for more
    details on radiometric and geometric processing of Magellan SAR data.
                                                                              
  References
  ==========
  
    Lewicki, S., Mosaicked Image Data Record (MIDR) Software Interface
    Specification, IDPS-109, Jet Propulsion Laboratory, Pasadena, Calif.,
    1991.

    Pettengill, G. H., Ford, P. G., Johnson, W. T. K., Raney, R. K.,
    Soderblom, L. A., Magellan: Radar Performance and Data Products, Science,
    V. 252, pp. 260-265, 1991.

    Saunders, R.S., G.H. Pettengill, R.E. Arvidson, W.L. Sjogren, W.T.K.
    Johnson, L. Pieri, The Magellan Venus Radar Mapping Mission, Journal of
    Geophysical Research, vol. 95, no. B6, pp. 8339-8355, June 10, 1990.
    
    Saunders, R. S., Pettengill, G. H., Magellan: Mission Summary, Science,
    V. 252, pp. 247-249, 1991.