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Web Services


3.7 Segments

The segment class represents a spectrum of SED itself. It has fields to describe sky and time coverage and spectral points, bins etc.

class Segment

The Segment class has the following members:

TextParam Type
Type of the segment, which can be spectrum, sed or timeseries according to the data model specifications.

TextParam Derivation
Derivation method of the SED, which can be observed, simulated, synthetic etc.

Frame Frame
Gives information about the sky coordinate system and time system of the observation.

Coverage Coverage
Gives information about the spatial, time and spectral coverage of the observation.

Curation Curation
Gives information about the observers and creators of the SED.

DataId DataId
Gives meta information about the SED. It has the PublisherID and CreatorID fields, which identify SEDs uniquely within the publishers and the creators database.

DerivedData DerivedData
Represents informations derived from the SED by scientific data analysis, such as redshift and signal-to-noise ratio.

Points Points

Gives information about the spectral points, bins, etc. It's not the array representing the points themselves, they're are stored in double arrays, see below.

Param[] Custom
Array of Param classes for custom parameters. Can store any number of parameters of any type.

The following arrays represent the spectral points. All arrays can be null except SpectralCoord_Value, Flux_Value, Flux_Accuracy_StatErrLow and Flux_Accuracy_StatErrorHigh, these are required by the functions of the Util web service.

double[] SpectralCoord_Value
Array of double values representing spectral coordinates, ie. wavelength, frequencies or energies. Spectrum Services currently support wavelength in Angstroms only.

double[] SpectralCoord_Accuracy_BinLow
double[] SpectralCoord_Accuracy_BinHigh
double[] SpectralCoord_Accuracy_BinSize
Arrays of double values representing the coverage of the bins of the spectral grid.

double[] SpectralCoord_Accuracy_StatErrLow
double[] SpectralCoord_Accuracy_StatErrHigh
Array of double values representing the absolute statistical error of the spectral coordinate values.

double[] Time_Value
Array of double values representing the elapsed time in seconds since an epoch defined in the Coverage object.

double[] Time_Accuracy_BinLow
double[] Time_Accuracy_BinHigh
double[] Time_Accuracy_BinSize
Arrays of double values representing the coverage of the bins of the time grid.

double[] Time_Accuracy_StatErrLow
double[] Time_Accuracy_StatErrHigh
Array of double values representing the absolute statistical error of the time coordinate values.

double[] Flux_Value
Array of double values representing the flux or flux density in the given spectral/time bin. Spectrum Services currently support flux density values with the following unit: 10-17 erg cm-2 s-1 A-1

double[] Flux_Accuracy_StatErrLow
double[] Flux_Accuracy_StatErrHigh
Arrays of double values representing the absolute statistical error of flux or flux density values. Both are required when pasing SEDs to the Util web service.

long[] Flux_Quality
Array of long (int64) values representing a quality mask of the spectrum. 0 means OK, all other values mean some kind of error of the measurement, depending on the data provider. The suggested way to use bit mask, like SDSS does.