org.esa.snap.core.datamodel

Class Stx

java.lang.Object

org.esa.snap.core.datamodel.Stx

public class Stx
extends Object

Provides statistic information for a raster data node at a given image resolution level. Instances of the Stx class are created using the StxFactory.

Important note: This class has been revised in BEAM 4.10. All behaviour has been moved to StxFactory leaving behind this class as a pure data container. Statistics are now furthermore derived upon geo-physically interpreted image data (before it operated on the raw, unscaled data). Thus, it is not required to scale the returned statistical properties, e.g. we used to write band.scale(stx.getMean). This is not required anymore.

Since:

BEAM 4.2, full revision in 4.10

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_BIN_COUNT
static Scaling	LOG10_SCALING

Constructor Summary

Constructors

Constructor and Description
Stx(double minimum, double maximum, double mean, double standardDeviation, double coeffOfVariation, double enl, boolean logHistogram, boolean intHistogram, javax.media.jai.Histogram histogram, int resolutionLevel) Constructor.

Method Summary

Modifier and Type	Method and Description
double	getCoefficientOfVariation()
double	getEquivalentNumberOfLooks()
javax.media.jai.Histogram	getHistogram() Gets the histogram computed from image samples.
int	getHistogramBinCount()
double	getHistogramBinMaximum(int binIndex) Gets the (exclusive) maximum value of the histogram bin given by the bin index.
double	getHistogramBinMinimum(int binIndex) Gets the (inclusive) minimum value of the histogram bin given by the bin index.
int[]	getHistogramBins()
double	getHistogramBinWidth() Gets the width of any histogram bin.
double	getHistogramBinWidth(int binIndex) Gets the width of the histogram bin given by the bin index.
Scaling	getHistogramScaling()
double	getMaximum()
double	getMean()
double	getMedian()
double	getMinimum()
int	getResolutionLevel()
long	getSampleCount()
double	getStandardDeviation()
boolean	isIntHistogram()
boolean	isLogHistogram()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DEFAULT_BIN_COUNT

public static final int DEFAULT_BIN_COUNT

See Also:

Constant Field Values

LOG10_SCALING

public static final Scaling LOG10_SCALING

Constructor Detail

Stx

public Stx(double minimum,
           double maximum,
           double mean,
           double standardDeviation,
           double coeffOfVariation,
           double enl,
           boolean logHistogram,
           boolean intHistogram,
           javax.media.jai.Histogram histogram,
           int resolutionLevel)

Constructor. Avoid using it directly. instead, use the StxFactory since the constructor may change in the future.

Parameters:

minimum - the minimum value, if it is Double.NaN the minimum is taken from the histogram

maximum - the maximum value, if it is Double.NaN the maximum is taken from the histogram

mean - the mean value, if it is Double.NaN the mean is taken from the histogram

standardDeviation - the value of the standard deviation, if it is Double.NaN it is taken from the histogram

coeffOfVariation - the Coefficient of Variation

enl - Equivalent number of looks

logHistogram - true if the histogram has been computed on logarithms, see getHistogram()

intHistogram - true if the histogram has been computed from integer samples, see getHistogram()

histogram - the histogram

resolutionLevel - the resolution level this Stx is for

Method Detail

getMinimum

public double getMinimum()

Returns:

The minimum value.

getMaximum

public double getMaximum()

Returns:

The maximum value.

getMean

public double getMean()

Returns:

The mean value.

getMedian

public double getMedian()

Returns:

The median value (estimation based on Gaussian distribution).

getStandardDeviation

public double getStandardDeviation()

Returns:

The standard deviation value.

getCoefficientOfVariation

public double getCoefficientOfVariation()

getEquivalentNumberOfLooks

public double getEquivalentNumberOfLooks()

getHistogram

public javax.media.jai.Histogram getHistogram()

Gets the histogram computed from image samples.

The returned histogram may have been computed on the logarithms of image samples. In this case isLogHistogram() returns true and it is expected that the histogram has been computed from logarithms (base 10) of image samples. Therefore, any statistical property retrieved from the returned histogram object such as low value, high value, bin low value, mean, moment, entropy, etc. must be raised to the power of 10. Scaling is best done using the getHistogramScaling() object.

The returned histogram may furthermore be computed from integer image data. In this case isIntHistogram() returns true and the high value of the histogram is by one higher than the value returned by getMinimum().

The numBands property of the histogram will always be 1.

Returns:

The histogram.

See Also:

isIntHistogram(), isLogHistogram(), getHistogramScaling()

isIntHistogram

public boolean isIntHistogram()

Returns:

true if the histogram is computed from integer samples.

See Also:

getHistogram()

isLogHistogram

public boolean isLogHistogram()

Returns:

true if the histogram is computed from log-samples.

See Also:

getHistogram(), getHistogramScaling()

getHistogramBinMinimum

public double getHistogramBinMinimum(int binIndex)

Gets the (inclusive) minimum value of the histogram bin given by the bin index.

The value returned is in units of the image samples, histogram scaling is already applied

Parameters:

binIndex - The bin index.

Returns:

The (inclusive) minimum value of the bin given by the bin index.

getHistogramBinMaximum

public double getHistogramBinMaximum(int binIndex)

Gets the (exclusive) maximum value of the histogram bin given by the bin index.

The value returned is in units of the image samples, histogram scaling is already applied

Parameters:

binIndex - The bin index.

Returns:

The (exclusive) maximum value of the bin given by the bin index.

getHistogramBinWidth

public double getHistogramBinWidth()

Gets the width of any histogram bin.

The method's return value is undefined if isLogHistogram() returns true. In this case you will have to use getHistogramBinWidth(int).

Returns:

The width of any histogram bin.

getHistogramBinWidth

public double getHistogramBinWidth(int binIndex)

Gets the width of the histogram bin given by the bin index.

The value returned is in units of the image samples, histogram scaling is already applied

Parameters:

binIndex - The bin index.

Returns:

The width of the bin given by the bin index.

getHistogramBins

public int[] getHistogramBins()

Returns:

The histogram bins (sample counts).

getHistogramBinCount

public int getHistogramBinCount()

Returns:

The number of bins.

getHistogramScaling

public Scaling getHistogramScaling()

Returns:

The image sample scaling used for deriving the histogram.

getSampleCount

public long getSampleCount()

Returns:

The total number of samples seen.

getResolutionLevel

public int getResolutionLevel()

Returns:

The image resolution level.