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CoastWatch Utils v3.4.0

Package noaa.coastwatch.util

Provides a number of data container, earth coordinate transformation, and polynomial approximation classes for use with earth locatable data.

See: Description

Package noaa.coastwatch.util Description

Provides a number of data container, earth coordinate transformation, and polynomial approximation classes for use with earth locatable data.

In order to manipulate satellite data in a generic way, it is useful to have the notion of a data variable -- a container that holds the data and any attributes it might have. The DataVariable class and its subclasses function as generic data containers. They allow the data values, name, units, scaling factors, and other attributes to be associated together in a single structure. The dimensions of a data variable depend on the specific subclass. Specifically, the Line class handles 1D data such as ship track, while the Grid class handles 2D gridded data such as satellite imagery with navigational corrections. The DataLocation class specifies coordinates that may be used to set and retrieve values within a data variable. The EarthDataInfo class binds a number of common DataVariable objects by providing the originating satellite, sensor, date, time, geolocation, and other common attributes.

The EarthTransform and subclasses DataProjection, MapProjection, and SwathProjection provide coordinate transformations between data coordinates such as (row, column) represented by the DataLocation class and geographic latitude and longitude coordinates represented by the EarthLocation class. The MapProjection class uses GCTP to provide cartographic transformations for some of the most commonly used map projections such as mercator, polar stereographic, and so on. Generic coordinate transforms are a required component of any data registration or resampling procedure. An EarthTransform object is typically used in conjunction with a number of DataVariable objects to translate between data and geographic coordinates. The EarthArea class may be used in conjunction with an EarthTransform to represent irregularly shaped areas on the Earth.

In some cases it may be necessary to approximate the value of a smooth function between a number of known function data values. The UnivariateEstimator, BivariateEstimator, and VariableEstimator provide polynomial estimation methods for this purpose. The VariableEstimator in particular is useful for approximating the value of a smoothly changing DataVariable such as latitude, longitude, satellite zenith, and other angle data. To aid in approximating smooth data fields with an appropriate number of known data points, the EarthPartition can be used to divide earth locatable data variables into subsections of a specified physical size.

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CoastWatch Utils v3.4.0