Glossary: CTX

ALL

  • Center Lat
    • Center areographic latitude
  • Center Lon
    • Center longitude
  • Data Quality
    • 'OK' if all fragments of the image are received without detected checksum or sequence errors, and 'ERROR' otherwise.
  • Description
    • A text description of the scientific purpose for the acquisition of this image. For routine mapping operations, this will most likely be the goal of the image as targeted (which may not be met if the image missed its target significantly, the atmosphere was cloudy, etc.)
  • Emission Angle
    • Measured from the center of the image, this is the angle between CTX and a "normal" drawn perpendicular to the planet's surface. In most cases, CTX is looking "straight down", thus, the emission angle is close to 0°.
  • File Specification Name
    • File name
  • Focal Plane Temperature
    • Focal plane temp in Kelvins
  • Image ID
    • Product id
  • Image Skew Angle
    • The image skew angle is the absolute value, in degrees, of the angle between the left edge (a line between the lower left and upper left corners) and the bottom edge (a line between the lower left and lower right corners) of the image, where the edges are projected on the target body. For images whose footprints are exactly rectangular, this angle will be 90 degrees. Departures from 90 degrees indicate a non-rectangular image footprint, caused by slews of the spacecraft during imaging outside the orbit plane or off-nadir pointing, or both.
  • Image Time
    • SCET time at start of image
  • Incidence Angle
    • Incidence angle at center of image
  • Instrument Id
    • Instrument id (abbreviated name or acronym)
  • Instrument Mode ID
    • Command mode (ITL or NIFL) in which this image was acquired
  • Line Exposure Duration
    • Line integration time in milliseconds
  • Lines
    • Image height
  • Line Samples
    • Image width
  • Local Time
    • Local True Solar Time in decimal hours from midnight at the center of the image, as computed by the method in 'Accurate analytic representations of solar time and seasons on Mars with applications to the Pathfinder/Surveyor missions', Michael Allison, Geophysical Reseach Letters 24, 16, pp 1967-1970 (August 15, 1997). An 'hour' in this context is an angular measure of 15 degrees of solar motion.
  • Lower Left Latitude
    • Lower left areographic latitude
  • Lower Left Longitude
    • Lower left longitude
  • Lower Right Latitude
    • Lower right areographic latitude
  • Lower Right Longitude
    • Lower right longitude
  • Mission Phase
    • Mission phase name
  • North Azimuth
    • The angle in degrees clockwise from the reference axis of the image (a line from the center to the right edge of the image) to the direction to the north pole of the target body. If the USAGE_NOTE described previously is 'F', the image should be flipped prior to applying this angle.
  • Offset Mode Id
    • Offset mode (see documentation)
  • Orbit
    • Orbit number as defined by the MRO Project
  • Original Product Id
    • Original product id
  • Phase Angle
    • Phase angle at center of image
  • Pixel Aspect Ratio
    • Pixel aspect ratio (pixel height/pixel width) at center of image. The image's center pixel is projected on the ground and its linear extents are ratioed, so any effects of emission angle and line time are modelled. To recover an image with 'square' pixels, the image should be resampled to a height of aspect_ratio * input height.
  • Sample First Pixel
    • First pixel stored from detector, zero-based
  • Scaled Image Height
    • Image height from first line to last line in km
  • Scaled Image Width
    • Image width from left to right image edge in km
  • Scaled Pixel Width
    • Image resolution in meters/pixel at center of image
  • Slant Distance
    • Range from s/c to intersection of view vector with target body in km
  • Solar Distance
    • Distance from the center of the image on the target body to the center of the sun in km
  • Solar Longitude
    • Solar longitude ('L sub s') at time of image in degrees from martian vernal equinox, as computed by the method in 'Accurate analytic representations of solar time and seasons on Mars with applications to the Pathfinder/Surveyor missions', Michael Allison, Geophysical Reseach Letters 24, 16, pp 1967-1970 (August 15, 1997)
  • Spacecraft Altitude
    • Distance from s/c to closest point on surface in km
  • Spacecraft Clock Start Count
    • Spacecraft clock value at start of image
  • Spatial Summing
    • Spatial summing
  • Subsolar Azimuth
    • The angle in degrees clockwise from the reference axis of the image (a line from the center to the right edge of the image) to the direction to the subsolar point on the target body. If the USAGE_NOTE described previously is 'F', the image should be flipped prior to applying this angle.
  • Subsolar Latitude
    • Planetographic latitude of subsolar point in degrees
  • Subsolar Longitude
    • West longitude of subsolar point in degrees
  • Subspacecraft Latitude
    • Planetographic latitude of subspacecraft point in degrees
  • Subspacecraft Longitude
    • West longitude of subspacecraft point in degrees
  • Target Center Distance
    • Distance from s/c to target body center in km
  • Target Name
    • Target name (e.g., MARS, PHOBOS, STAR, SPACE)
  • Upper Left Latitude
    • Upper left areographic latitude
  • Upper Left Longitude
    • Upper left longitude
  • Upper Right Latitude
    • Upper right areographic latitude
  • Upper Right Longitude
    • Upper right longitude
  • Usage Note
    • Because of the CTX's line-scan nature, depending on the orientation and sense of rotation of the spacecraft, CTX images can either be normal or flipped left-for-right (independent of whether the image is north up or south up.) This flag will be 'F' if the image should be flipped left-to-right, and 'N' if it is already in normal form.
  • Volume ID
    • Volume id