[seiscomp, scanloc] Install, add .gitignore

include/seiscomp/processing/amplitudes/iaspei.h

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+/***************************************************************************
+ * Copyright (C) gempa GmbH                                                *
+ * All rights reserved.                                                    *
+ * Contact: gempa GmbH (seiscomp-dev@gempa.de)                             *
+ *                                                                         *
+ * GNU Affero General Public License Usage                                 *
+ * This file may be used under the terms of the GNU Affero                 *
+ * Public License version 3.0 as published by the Free Software Foundation *
+ * and appearing in the file LICENSE included in the packaging of this     *
+ * file. Please review the following information to ensure the GNU Affero  *
+ * Public License version 3.0 requirements will be met:                    *
+ * https://www.gnu.org/licenses/agpl-3.0.html.                             *
+ *                                                                         *
+ * Other Usage                                                             *
+ * Alternatively, this file may be used in accordance with the terms and   *
+ * conditions contained in a signed written agreement between you and      *
+ * gempa GmbH.                                                             *
+ ***************************************************************************/
+
+
+#ifndef SEISCOMP_PROCESSING_IASPEI_H_INCLUDED
+#define SEISCOMP_PROCESSING_IASPEI_H_INCLUDED
+
+
+#include <vector>
+
+
+namespace Seiscomp {
+namespace Processing {
+namespace IASPEI {
+
+
+// IASPEI Amplitude Measurement Procedure
+//
+// From:
+// Summary of Magnitude Working Group Recommendations on Standard Procedures
+// for Determining Earthquake Magnitudes From Digital Data - 2013 March 27
+//
+// Amplitudes [...] to be measured as one-half the maximum deflection of the
+// seismogram trace, peak-to-adjacent- trough or trough-to-adjacent-peak,
+// where peak and trough are separated by one crossing of the zero-line: the
+// measurement is sometimes described as "one-half peak-to-peak amplitude."
+// None of the magnitude formulas presented in this article are intended to
+// be used with the full peak-to-trough deflection as the amplitude. The
+// periods are to be measured as twice the time-intervals separating the
+// peak and adjacent-trough from which the amplitudes are measured.
+
+
+struct AmplitudePeriodMeasurement
+{
+	// Amplitudes
+	//
+	// Note that "peak" here refers to both maxima and minima and
+	// thus can also refer to a trough. So peak-to-peak is either
+	// peak-to-trough or trough-to-peak. Just to avoid confusion.
+	//
+	// - az2p Max. zero-to-peak amplitude found at index iz2p
+	// - ap2p1 first peak of the max. peak-to-peak amplitude pair
+	// - ap2p2 second peak
+	//
+	// Note that az2p is the larger of ap2p1 and ap2p2.
+
+	double az2p;
+	double ap2p1;
+	double ap2p2;
+
+	// Sample indices corresponding the above peaks
+	std::size_t iz2p;
+	std::size_t ip2p1;
+	std::size_t ip2p2;
+
+	// From the above numbers we can now derive:
+	//
+	// - Period in sampling intervals:
+	//
+	//   (ip2p2 - ip2p1)*2
+	//
+	//   To be divided by the sampling rate in order to get the period
+	//   in seconds.
+	//
+	//
+	// - One half of the max. peak-to-peak amplitude in data units:
+	//
+	//   (ap2p1 + ap2p2)/2
+	//
+	//
+	// - Time of measurement as offset from first sample of the middle
+	//   of the two peaks:
+	//
+	//   (ip2p1 + ip2p2)/2
+	//
+	//   To be divided by the sampling rate in order to get the time
+	//   in seconds.
+};
+
+
+// Compute amplitude and dominant period for the given data vector.
+//
+// The data may have an offset to be removed during the amplitude measurement.
+// If dealing with demeaned data the offset should be zero.
+//
+// We only work on the time window between samples istart and iend.
+//
+// A reference to a struct AmplitudePeriodMeasurement is speciefied, where the
+// result will be written to. See above for details.
+bool measureAmplitudePeriod(
+	const std::vector<double> &data,
+	double offset,
+	std::size_t istart,
+	std::size_t iend,
+	AmplitudePeriodMeasurement &measurement
+);
+
+
+// Interface for raw pointer.
+bool measureAmplitudePeriod(
+	std::size_t ndata,
+	const double *data,
+	double offset,
+	std::size_t istart,
+	std::size_t iend,
+	AmplitudePeriodMeasurement &measurement
+);
+
+
+/**
+ * @brief Finds a zero crossing within the data portion.
+ * @param n The number of samples
+ * @param data The data pointer
+ * @param offset An optional data offset which is removed from each sample checked.
+ * @param istart Index to start from
+ * @param iend Index before to end
+ * @return The zero crossing index or -1 if none was found.
+ */
+double findZeroCrossing(
+	std::size_t n,
+	const double *data,
+	double offset,
+	std::size_t istart,
+	std::size_t iend
+);
+
+
+/**
+ * @brief Finds a zero crossing within the data portion.
+ * @param data The data vector
+ * @param offset An optional data offset which is removed from each sample checked.
+ * @param istart Index to start from
+ * @param iend Index before to end
+ * @return The zero crossing index or -1 if none was found.
+ */
+double findZeroCrossing(
+	const std::vector<double> &data,
+	double offset,
+	std::size_t istart,
+	std::size_t iend
+);
+
+
+// Compute the WWSSN-SP displacement amplitude response needed for the
+// mb amplitude correction.
+//
+// The response is based on the poles and zeros specified in the IASPEI
+// Magnitude Working Group Recommendations.
+double wwssnspAmplitudeResponse(double frequency_hz);
+
+
+} // namespace IASPEI
+} // namespace Processing
+} // namespace Seiscomp
+
+
+#endif