imageDescription: imageDescription
In cboettig/build.eml: Build Ecological Metadata Language Files

imageDescription

imageDescription(illuminationElevationAngle = NULL,
  illuminationAzimuthAngle = NULL, imageOrientationAngle = NULL,
  imagingCondition = NULL, imageQualityCode = NULL,
  cloudCoverPercentage = NULL, preProcessingTypeCode = NULL,
  compressionGenerationQuality = NULL, triangulationIndicator = NULL,
  radiometricDataAvailability = NULL,
  cameraCalibrationInformationAvailability = NULL,
  filmDistortionInformationAvailability = NULL,
  lensDistortionInformationAvailability = NULL, bandDescription = NULL)

`illuminationElevationAngle`	Illumination elevation measured in degrees clockwise from the target plane at intersection of the optical line of sight with the earth's surface. See `illuminationElevationAngle()`
`illuminationAzimuthAngle`	Illumination azimuth measured in degrees clockwise from true north at the time the image is taken. See `illuminationAzimuthAngle()`
`imageOrientationAngle`	Angle from the first row of the image to true north in degrees, clockwise. See `imageOrientationAngle()`
`imagingCondition`	Code which indicates conditions which affect the quality of the image. See `imagingCondition()`
`imageQualityCode`	Specifies the image quality. See `imageQualityCode()`
`cloudCoverPercentage`	Area of the dataset obscured by clouds, expressed as a percentage of the spatial extent. See `cloudCoverPercentage()`
`preProcessingTypeCode`	Image distributor's code that identifies the level of radiometric and geometric processing applied against the image. See `preProcessingTypeCode()`
`compressionGenerationQuality`	Counts the number of lossy compression cycles performed on the image. See `compressionGenerationQuality()`
`triangulationIndicator`	Code which indicates whether or not triangulation has been performed upon the image. See `triangulationIndicator()`
`radiometricDataAvailability`	Code which indicates whether or not Standard Radiometric Product data is available. See `radiometricDataAvailability()`
`cameraCalibrationInformationAvailability`	Code which indicates whether or not constants are available which allow for camera calibration corrections. See `cameraCalibrationInformationAvailability()`
`filmDistortionInformationAvailability`	Code which indicates whether or not Calibration Reseau information is available See `filmDistortionInformationAvailability()`
`lensDistortionInformationAvailability`	Code which indicates whether or not lens aberration correction information is available See `lensDistortionInformationAvailability()`
`bandDescription`	Description of the wavelength domain that the sensor operates in. See `bandDescription()`