torsten
77c67c12ca
Entire-Metadata: .entire/metadata/fb87247f-2a75-407e-b336-cbc8c20ba5a6 Entire-Session: fb87247f-2a75-407e-b336-cbc8c20ba5a6 Entire-Strategy: manual-commit
46 lines
1.5 KiB
C++
46 lines
1.5 KiB
C++
// Write the coefficient files needed for approximating the normal gravity
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// field with a GravityModel. WARNING: this creates files, wgs84.egm.cof and
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// grs80.egm.cof, in the current directory.
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#include <cmath>
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#include <fstream>
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#include <iostream>
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#include <GeographicLib/NormalGravity.hpp>
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#include <GeographicLib/Utility.hpp>
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using namespace std;
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using namespace GeographicLib;
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int main() {
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try {
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Utility::set_digits();
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const char* filenames[] = {"wgs84.egm.cof", "grs80.egm.cof"};
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const char* ids[] = {"WGS1984A", "GRS1980A"};
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for (int grs80 = 0; grs80 < 2; ++grs80) {
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ofstream file(filenames[grs80], ios::binary);
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Utility::writearray<char, char, false>(file, ids[grs80], 8);
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const int N = 20, M = 0,
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cnum = (M + 1) * (2 * N - M + 2) / 2; // cnum = N + 1
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vector<int> num(2);
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num[0] = N; num[1] = M;
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Utility::writearray<int, int, false>(file, num);
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vector<Math::real> c(cnum, 0);
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const NormalGravity& earth(grs80 ? NormalGravity::GRS80() :
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NormalGravity::WGS84());
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for (int n = 2; n <= N; n += 2)
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c[n] = - earth.DynamicalFormFactor(n) / sqrt(Math::real(2*n + 1));
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Utility::writearray<double, Math::real, false>(file, c);
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num[0] = num[1] = -1;
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Utility::writearray<int, int, false>(file, num);
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}
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}
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catch (const exception& e) {
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cerr << "Caught exception: " << e.what() << "\n";
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return 1;
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}
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catch (...) {
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cerr << "Caught unknown exception\n";
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return 1;
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}
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}
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