L1AuxiliaryProcessorParameters version 4

xml record

Product auxiliary parameters. This DSR contains all of the auxiliary parameters required to process a single product. The parameters are stored in structures that are grouped together by the logical processing steps used during image creation. The parameters within this DSR and its children are not polarisation dependent and in general apply to the entire product; however, in some cases a distinction must be made amongst swaths and when this is necessary the records are indexed with a swath identifier. id field name definition 0 productId xml string Product type identifier as per S1 IPF ICD to which this set of parameters applies. The productId is used to index and find the correct set of auxiliary parameters for each product the IPF is capable of generating. 1 commonProcParams xml record Common processing auxiliary parameters. This record holds the parameters that are common among multiple steps in the image processing chain. id field name definition 0 correctIQBiasFlag ascii uint8 Flag to control the correction of the constant biases from the I and Q channels. IQ bias correction will be performed if and only if this flag is set to "true". mapping: "false" -> 0 mapping: "true" -> 1 1 correctIQGainImbalanceFlag ascii uint8 Flag to control the correction of the IQ gain imbalance. IQ gain imbalance correction will be performed if and only if this flag is set to "true". mapping: "false" -> 0 mapping: "true" -> 1 2 correctIQOrthogonalityFlag ascii uint8 Flag to control the correction of the IQ orthogonality. IQ orthorgonality correction will be performed if and only if this flag is set to "true". mapping: "false" -> 0 mapping: "true" -> 1 3 correctBistaticDelayFlag ascii uint8 Flag to compensate for the bi-static delay. Correction will be performed if and only if this flag is set to "true". mapping: "false" -> 0 mapping: "true" -> 1 4 correctBistaticDelayMethod xml string Method used to compensate for the bi-static delay. If set to "Coarse" then only the coarse bistatic delay correction is applied; otherwise, if set to "Fine" then the full correction is applied. Flag introduced starting from IPF V290. 5 correctRxVariationFlag ascii uint8 Flag to control the correction of the gain variation across the receive window. Receive variation correction will be performed if and only this flag is set to "true". mapping: "false" -> 0 mapping: "true" -> 1 6 computeBurstIdsFlag ascii uint8 Flag to control the computation of the relative and absolute BurstIDs. Computation will be performed if this flag is set to "true" otherwise a fill value (0) will be used. mapping: "false" -> 0 mapping: "true" -> 1 available: optional 7 ellipsoidParams xml record Ellipsoid and DEM parameters. id field name definition 0 ellipsoidName xml string Name of the reference ellipsoid. 1 ellipsoidSemiMajorAxis ascii double Semi-major axis of ellipsoid [m]. unit: "m" 2 ellipsoidSemiMinorAxis ascii double Semi-minor axis of ellipsoid [m]. unit: "m" 3 useDemFlag ascii uint8 This flag is used to control the use of a DEM during processing. Set to true if a DEM is to be used during processing, false otherwise. mapping: "false" -> 0 mapping: "true" -> 1 8 aziProcBlockParamsList xml record Azimuth processing block parameters record indexed by swath. There will be one record per swath. attribute: count xml string id field name definition 0 aziProcBlockParams xml array[dim_0] dim_0: determined automatically from xml file xml record Azimuth processing block parameters record indexed by swath. There will be one record per swath. id field name definition 0 swath xml string Swath identifier. This parameter defines the swath to which this record applies. 1 aziProcBandwidth ascii float Total processing bandwidth [Hz] (excluding any additional bandwidth resulting from the taperBwExtentFraction). This parameter defines the bandwidth (Bw) to use during processing. The processing bandwidth (Bw) must be 0 < Bw <= PRF. 2 aziBlockSize ascii uint32 Azimuth processing block size [lines]. 3 extraAziProcBlockOverlap ascii uint32 Extra azimuth block overlap to account for possible variation of Doppler centroid frequency from azimuth block to azimuth block [lines]. 4 maxFdc ascii array[dim_0] Maximum expected Doppler centroid frequency [Hz]. Used to calculate the SM SLC azimuth matched filter throwaway component of azimuth block overlap as applicable to all azimuth blocks in a segment. dim_0: if(exists(@count), int(str(@count)), 1) attribute: count ascii string available: optional ascii float 9 outputMeanExpected ascii double This parameter specifies the expected mean of the samples in the output image and is used for verifying that the calculated mean of the output samples is within the tolerated threshold. 10 outputMeanThreshold ascii double Threshold for setting the outputDataMeanOutsideNominalRange flag in the output product annotations. This is the value T, such that the measured mean must fall between the outputMeanExpected-T and outputMeanExpected+T. 11 outputStdDevExpected ascii double This parameter specifies the expected standard deviation of the samples in the output image and is used for verifying that the calculated std. dev. of the output samples is within the tolerated threshold. 12 outputStdDevThreshold ascii double Threshold for setting the outputDataStdDevOutsideNominalRange flag in the output product annotations. This is the value D, such that the measured standard deviation must fall between the outputStdDevExpected-D and outputStdDevExpected+D. 13 topsFilterConvention xml string Name of the TOPS filter convention to use during processing. This field controls how the TOPS ramping/de-ramping filters are defined. If set to "Only Echo Lines" then the filter is defined using only the echo lines in a burst; otherwise, if set to "All Lines" then the filter is defined using all the lines in a burst. 14 orbitModelMargin ascii double Additional time to add to the start and end of the orbit model generated by the IPF [s]. This provides margin for performing interpolation near the boundaries of the sensing start and stop times and extrapolation beyond the boundaries of the sensing start and stop times. For example, if the sensing start time is Tstart, the sensing stop time is Tstop and orbitModelMargin is 2.0, then the orbit model generated by the IPF will range from (Tstart - 2.0) .. (Tstop + 2.0) available: optional 2 preProcParams xml record Pre-processing auxiliary parameters. This record contains the auxiliary parameters required during image pre-processing. id field name definition 0 inputMeanExpected ascii double This parameter specifies the expected mean of the input I and Q samples and is used in verifying that the calculated mean of the input samples is within the tolerated threshold. 1 inputMeanThreshold ascii double Threshold for setting the inputDataMeanOutsideNominalRange flag in the output product annotations. This is the value T, such that the measured mean must fall between the inputMeanExpected-T and inputMeanExpected+T. This threshold is used for both the I and Q channels. 2 inputStdDevExpected ascii double This parameter specifies the expected standard deviation of the input I and Q samples and is used in verifying that the calculated std. dev. of the input samples is within the tolerated threshold. 3 inputStdDevThreshold ascii double Threshold for setting the inputDataStdDevOutsideNominalRange flag in the output product annotations. This is the value D, such that the measured std. dev. must fall between the inputStdDevExpected-D and inputStdDevExpected+D. This threshold is used for both the I and Q channels. 4 terrainHeightAziSpacing ascii double Spacing of terrain height estimates along azimuth [s]. The calculation, terrainHeightAziSpacing + terrainHeightAziBlockSize, defines the location (relative to the start of the segment) and size of the azimuth blocks used to generate each terrain height estimate. These two parameters should be set to ensure that there is an overlapping region within each adjacent azimuth block. unit: "s" 5 terrainHeightAziBlockSize ascii double Size of the block along azimuth used to calculate an average terrain height [s]. The calculation, terrainHeightAziSpacing + terrainHeightAziBlockSize, defines the location (relative to the start of the segment) and size of the azimuth blocks used to generate each terrain height. . These parameters should be set to ensure that there is an overlapping region within each adjacent azimuth block. unit: "s" 6 chirpReplicaSource xml string Chirp replica to use during processing. The extracted replica will be used if this parameter is set to "Extracted" and the IPF determines that the reconstructed replica is valid; otherwise, the nominal chirp will be used if this field is set to "Nominal" or the reconstructed replica is deemed invalid. 7 replicaThresholds xml record Thresholds used to assess the quality of the replica reconstruction and the PG product. id field name definition 0 maxXCorrPulseIrw ascii double Maximum allowable IRW (3-dB width) of the cross-correlation with the nominal replica [samples]. Used for setting the replicaReconstructionFailedFlag in the output product annotations. 1 maxXCorrPulsePslr ascii double Maximum allowable PSLR of the cross correlation with the nominal replica [dB]. Used for setting the replicaReconstructionFailedFlag in the output product annotations. unit: "dB" 2 maxXCorrPulseIslr ascii double Maximum allowable ISLR of the cross correlation with the nominal replica [dB]. Used for setting the replicaReconstructionFailedFlag in the output product annotations. unit: "dB" 3 maxPgAmpStdFraction ascii float Maximum deviation from the mean allowed for the PG product amplitude, measured as a fraction of the standard deviation. Relative PG product validation shall fail if this value is exceeded. 4 maxPgPhaseStdFraction ascii float Maximum deviation from the mean allowed for the PG product phase, measured as a fraction of the standard deviation. Relative PG product validation shall fail if this value is exceeded. 5 maxPgAmpError ascii float Maximum deviation allowed for a PG product amplitude from the corresponding PG product model value. Absolute PG product validation shall fail if this value is exceeded. 6 maxPgPhaseError ascii float Maximum deviation allowed for a PG product phase from the corresponding PG product model value [radians]. Absolute PG product validation shall fail if this value is exceeded. unit: "radians" 7 maxNumInvalidPgValFraction ascii float Maximum number of invalid PG product values allowed, expressed as a fraction of the total number of PG values. The PG product model will be used instead of the extracted PG product values if this value is exceeded. 8 missingLinesThreshold ascii double Threshold for setting the missingLinesSignificant flag in the output product annotations. This parameter ranges between 0 and 1 and specifies the percentage of missing lines to total lines [%]. For TOPS products, this threshold is relative to each individual swath, in other words the missingLinesSignificant flag is set to true if the number of missing lines in any of the swaths is above the missingLinesThreshold. unit: "%" 9 linesPerGapThreshold ascii uint32 This parameter specifies the number of consecutive missing lines in the input data which constitute a gap [lines]. 10 missingGapsThreshold ascii uint32 Threshold for setting the significantGapsInInputData flag in the output product annotations. This parameter specifies the number of missing gaps permitted in the input data. For TOPS products, this threshold is relative to each individual swath, in other words the significantGapsInInputData flag is set to true if the number of missing gaps in any of the swaths is above the missingGapsThreshold. 11 performInternalCalibrationFlag ascii uint8 Flag controlling the calculation of the internal calibration from the calibration pulses extracted from the downlink. If this flag is set to true then the internal calibration information will be calculated by the IPF using the calibration pulses extracted from the downlink. If this flag is set to false then the internal calibration information will not be calculated from the calibration pulses extracted from the downlink. In addition, if this flag is set to false, the values provided for chirpReplicaSource and pgSource will be ignored and set to "Nominal" and "Model" espectively. mapping: "false" -> 0 mapping: "true" -> 1 12 pgSource xml string PG source to use during processing. The PG derived from the extracted replica will be used if this parameter is set to "Extracted" and the IPF determines that the reconstructed replica is valid; otherwise, the pgModel from the AUX_INS data will be used if this field is set to "Model" or the reconstructed replica is deemed invalid. 13 estimateNoiseEquivalentPowerFlag ascii uint8 Flag introduced starting from IPF V290 to manage the new L0N products format including also noise-equivalent echoes. If set to true, then the noise power is estimated also from the noise equivalent echoes; otherwise, if set to false only pure noise echoes are used. mapping: "false" -> 0 mapping: "true" -> 1 available: optional 3 rfiProcParams xml record RFI detection and mitigation parameters. id field name definition 0 rfiPreScreeningParams xml record The parameters needed for RFI pre-screening. id field name definition 0 detectRfiFromNoise ascii uint8 Flag to activate the RFI detection from noise echoes. mapping: "false" -> 0 mapping: "true" -> 1 1 thresholdKL ascii double Threshold on KL Divergence. 2 thresholdZ ascii double Threshold on Fisher's Z test. 3 useAndOperatorTests ascii uint8 If true use an AND operator on the result of the tests, otherwise OR. mapping: "false" -> 0 mapping: "true" -> 1 4 maFilterOrder ascii uint32 Order of the moving average filter applied on the spectrum. 5 frequencyBinStep ascii double Width in Hz of the frequency bins used to partition the frequency axis. 6 numPSDHistogramBins ascii uint32 Number of bins used to compute the PSD histogram. 1 rfiTimeDomainParams xml record The parameters needed for RFI mitigation in time domain. id field name definition 0 medianFilterBlockLines ascii uint32 Number of range lines to be used to compute the local median filter. 1 boxFilterAzimuthDimension ascii uint32 Dimension along the azimuth direction of the convolution block used to compute the local percentiles of the signal distribution. 2 boxFilterRangeDimension ascii uint32 Dimension along the range direction of the convolution block used to compute the local percentiles of the signal distribution. 3 percentileThreshold ascii double Percentile of the signal distribution model to be tuned. Lower values imply more false positives. Possible values range from 0.0 to 1.0. 4 morphOpenLineLength ascii uint32 Length of the line patter used for the morphological-open filter. 5 morphCloseLineLength ascii uint32 Length of the line patter used for the morphological-close filter. 6 corrMethod xml string Length of the line patter used for the morphological-close filter. 2 rfiFrequencyDomainParams xml record The parameters needed for RFI mitigation in frequency domain. id field name definition 0 numBlocks ascii uint32 Number of blocks in which the data is split for RFI mitigation. 1 blockOverlapLines ascii uint32 Number of overlap lines between blocks for RFI mitigation. 2 useSyntheticChirp ascii uint8 Elevation antenna pattern correction flag. True if the EAP is to be applied, false otherwise. mapping: "false" -> 0 mapping: "true" -> 1 3 periodogramSize ascii uint32 Size of the single-echo PSD computed using the Welch method for isolated RFI detection. 4 persistentRFIThreshold ascii double Threshold in DB for persistent RFI detection. 5 isolatedRFIThreshold ascii double Threshold in DB for isolated RFI detection. 6 thresholdStd ascii double If the standard deviation of the power difference (in DB) between the echo PSD and the expected echo power for current line is below this threshold, then all the echo is marked as isolated RFI. 7 quantileLow ascii double Minimum quantile used for computing expected echo power. Only the values above this quantile are used for polynomial fitting. 8 quantileHigh ascii double Maximum quantile used for computing expected echo power. Only the values below this quantile are used for polynomial fitting. available: optional 4 dcProcParams xml record Doppler centroid processing auxiliary parameters. This record contains the auxiliary parameters required during Doppler centroid processing. id field name definition 0 dcMethod xml string Doppler centroid estimation method. Although the DCE from both orbit & attitude and data are always performed and the results provided in the output product annotations, this parameter is used to specify exactly which Doppler centroid estimation method to use during the image focusing. 1 dcInputData xml string Type of input data used for Doppler centroid estimation. Options are "Raw" and "Range Compressed". 2 dcPredefinedCoefficients ascii array[dim_0] Pre-defined Doppler centroid coefficients. These Doppler centroid coefficients shall be used during processing if and only if the dcMethod element is set to "Pre-defined". This parameter is an array of floating point numbers separated by spaces. dim_0: int(str(@count)) attribute: count ascii string ascii float 3 dcRmsErrorThreshold ascii float Doppler centroid estimation root mean squared (RMS) error threshold. If theRMS error of the Doppler centroid estimate from data is above this threshold they shall not be used during processing; instead, the Doppler centroid calculated from orbit and attitude shall be used, unless overridden by the dcMethod = Pre-defined. available: optional 5 slcProcParams xml record SLC processing auxiliary parameters. This record contains the auxiliary parameters required during SLC image processing. id field name definition 0 applyElevationAntennaPatternFlag ascii uint8 Elevation antenna pattern correction flag. True if the EAP is to be applied, false otherwise. mapping: "false" -> 0 mapping: "true" -> 1 1 applyRangeSpreadingLossFlag ascii uint8 Apply range spreading loss correction flag. True if the RSL is to be applied, false otherwise. mapping: "false" -> 0 mapping: "true" -> 1 2 estimateThermalNoiseFlag ascii uint8 Thermal noise estimation flag. True if thermal noise estimation is to be performed, false otherwise. mapping: "false" -> 0 mapping: "true" -> 1 3 rfiMitigationPerformed xml string Whether or not to perform the RFI mitigation step: if "Always" the RFI mitigation step is always performed; if "Never" the RFI mitigation step is not performed; if "BasedOnNoiseMeas" the preliminary RFI detection from noise measurements decides whether to perform RFI mitigation. 4 rfiMitigationDomain xml string In case the RFI mitigation step is performed, this flag indicates in what domain it has to be applied: "Time", "Frequency", "TimeAndFrequency". 5 rrfSpectrum xml string The type of range matched filter to use during processing. "Unextended": range reference function is unextended in frequency domain; "Extended Flat": range reference function is extended and flat in frequency domain; and, "Extended Tapered": range reference function is extended and tapered in frequency domain. 6 swathParamsList xml record List of swath-dependent SLC processing parameters. There is one record per swath for each mode. attribute: count xml string id field name definition 0 swathParams xml array[dim_0] dim_0: determined automatically from xml file xml record id field name definition 0 swath xml string Swath identifier. This parameter defines the swath to which this record applies. 1 gain ascii array[dim_0] Product specific gain. This parameter defines the gain that is applied to each output sample during azimuth processing. dim_0: if(exists(@count), int(str(@count)), 1) attribute: count ascii string available: optional ascii double 2 instantaneousBandwidth ascii float Azimuth instantaneous bandwidth [Hz]. This field is applicable only to IW and EW modes. unit: "Hz" 3 nominalBeamWidth ascii double Nominal width of the beam [radians]. unit: "radians" available: optional 6 postProcParams xml record Post processing auxiliary parameters. This record contains the auxiliary parameters required during image post processing. This includes: SLC post-processing, GRD processing and Quick-look image processing. id field name definition 0 rangeParamsList xml record Range processing parameters. This list contains the swath-dependent auxiliary parameters required for range processing. The list contains a separate record for each swath, indexed using the applicable swath identifier. For SM SLC products and SM, IW and EW GRD products there is one entry in the list. For IW and EW SLC products, there is one entry per swath (3 and 5 respectively). For all WV products there are two entries in the list. attribute: count xml string id field name definition 0 rangeParams xml array[dim_0] dim_0: determined automatically from xml file xml record This record contains the set of auxiliary parameters required during range processing. For each product type, there is one record for each applicable swath within the product. There will be one record per swath for each mode. For example, for S1 IW there will be 3 records, and for ASAR IM there will be 7 records. id field name definition 0 swath xml string Swath identifier. This parameter defines the swath to which this record applies. 1 weightingWindow xml string Name of the weighting window to use during processing. 2 windowCoefficient ascii double Value of the weighting window coefficient to use during processing. 3 processingBandwidth ascii double Total processing bandwidth [Hz]. This parameter defines the bandwidth (Bw) to use during processing. For range, the processing bandwidth (Bw) must be 0 < Bw <= pulse Bw, for azimuth the processing bandwidth (Bw) must be 0 < Bw <= PRF. unit: "Hz" 4 lookBandwidth ascii double Look bandwidth [Hz]. This parameter defines the bandwidth to use for each look during processing. unit: "Hz" 5 numberOfLooks ascii uint32 Number of looks. This parameter defines the number of looks to use during multi-look processing. 6 pixelSpacing ascii double Spacing between pixels in the output image [m]. unit: "m" 7 multiLookThrowaway ascii int32 Number of ground range samples to be discarded at both edges. 1 azimuthParamsList xml record Azimuth processing parameters. This list contains the swath-dependent auxiliary parameters required for azimuth processing. The list contains a separate record for each swath, indexed using the applicable swath identifier. For SM SLC products and SM, IW and EW GRD products there is one entry in the list. For IW and EW SLC products, there is one entry per swath (3 and 5 respectively). For all WV products there are two entries in the list. attribute: count xml string id field name definition 0 azimuthParams xml array[dim_0] dim_0: determined automatically from xml file xml record This record contains the set of auxiliary parameters required during azimuth processing. For each product type, there is one record for each applicable swath within the product. There will be one record per swath for each mode. For example, for S1 IW there will be 3 records, and for ASAR IM there will be 7 records. id field name definition 0 swath xml string Swath identifier. This parameter defines the swath to which this record applies. 1 weightingWindow xml string Name of the weighting window to use during processing. 2 windowCoefficient ascii double Value of the weighting window coefficient to use during processing. 3 processingBandwidth ascii double Total processing bandwidth [Hz]. This parameter defines the bandwidth (Bw) to use during processing. For range, the processing bandwidth (Bw) must be 0 < Bw <= pulse Bw, for azimuth the processing bandwidth (Bw) must be 0 < Bw <= PRF. unit: "Hz" 4 lookBandwidth ascii double Look bandwidth [Hz]. This parameter defines the bandwidth to use for each look during processing. unit: "Hz" 5 numberOfLooks ascii uint32 Number of looks. This parameter defines the number of looks to use during multi-look processing. 6 pixelSpacing ascii double Spacing between pixels in the output image [m]. unit: "m" 7 multiLookThrowaway ascii int32 Number of ground range samples to be discarded at both edges. 2 annotationVectorStepSize ascii uint32 The decimation factor used on annotation vectors when written to the output product. Inside the IPF, each annotation vector could have a point for every range sample. To reduce product size, only points every annotationVectorStepSize are written to the output annotation vectors. 3 generateCalibrationLutsFlag ascii uint8 Flag to control the generation of the absolute calibration LUTs. True if the calibration LUTs are to be created, false otherwise. mapping: "false" -> 0 mapping: "true" -> 1 4 applyAzimuthAntennaPatternFlag ascii uint8 Azimuth Antenna Pattern Flag. True if the AAP is to be applied, false otherwise. mapping: "false" -> 0 mapping: "true" -> 1 5 applyTopsDescallopingFlag ascii uint8 Perform de-scalloping for TOPS by applying the Azimuth Antenna Element Pattern. True if TOPS de-scalloping is to be performed by applying the AAEP, false otherwise. This flag is applicable only to IW and EW modes and is ignored for all others. mapping: "false" -> 0 mapping: "true" -> 1 6 detectFlag ascii uint8 True to detect power and square root extract measurement data, false otherwise. mapping: "false" -> 0 mapping: "true" -> 1 7 mergeFlag ascii uint8 True to merge the swaths of output data and annotations, false otherwise. Only valid for IW and EW, not applicable to other modes. mapping: "false" -> 0 mapping: "true" -> 1 8 createInternalSLCFlag ascii uint8 True if the output of post-processing is an internal SLC product, in which case post-processing will pass the input SLC product through without applying further processing. mapping: "false" -> 0 mapping: "true" -> 1 9 grdProcParams xml record GRD processing auxiliary parameters. This record contains the auxiliary parameters required during GRD image processing. id field name definition 0 applySrgrConversionFlag ascii uint8 Slant Range to Ground Range (SRGR) conversion flag. True if SRGR conversion is to be performed, false otherwise. mapping: "false" -> 0 mapping: "true" -> 1 1 removeThermalNoiseFlag ascii uint8 Thermal noise removal flag. True if thermal noise removal is to be performed, false otherwise. mapping: "false" -> 0 mapping: "true" -> 1 10 createQlImageFlag ascii uint8 Create Quick-look image flag. This flag controls the creation of a Quick-look image. It is set to true if a Quick-look image should be created; or, false otherwise. mapping: "false" -> 0 mapping: "true" -> 1 11 qlProcParams xml record Quick-look processing auxiliary parameters. This record contains the auxiliary parameters required during Quick-look image processing. This structure need only be present if the createQlImageFlag is true. id field name definition 0 rangeDecimationFactor ascii uint32 Range decimation factor for the image. 1 rangeAveragingFactor ascii uint32 Range averaging factor for the image. 2 azimuthDecimationFactor ascii uint32 Azimuth decimation factor for the image. 3 azimuthAveragingFactor ascii uint32 Azimuth averaging factor for the image. available: optional

xml record

Application LUT record. This element contains the information required to identify the application scaling LUT specified in the Job Order. The ICD currently defines four application scaling LUTs, one for each mode. However, more can be added, so long as the applicationLutId matches the Application_LUT processing parameter in the Job Order. id field name definition 0 applicationLutId xml string Name of this application scaling LUT. 1 scalingLutList xml record List of application scaling LUTs for this applicationLutId. There is one entry for each output pixel type. attribute: count xml string id field name definition 0 scalingLut xml array[dim_0] dim_0: determined automatically from xml file xml record Application scaling LUT record. This record provides the scaling LUT for products in the format specified by the outputPixels field. id field name definition 0 outputPixels xml string Pixel format. Application scaling LUTs are specific to output pixel data type. This field specifies the output pixel type to which this LUT applies. 1 incidenceAngleStart ascii double Incidence angle of the first value of the LUT [degrees]. unit: "degrees" 2 angleIncrement ascii double Step size of the incidence angle between each value [degrees]. unit: "degrees" 3 values ascii array[dim_0] Application LUT values. This element is a vector containing attribute "count" floating point values separated by spaces [linear]. dim_0: int(str(@count)) attribute: count ascii string ascii float