セミ・ダイナミック補正

地殻変動補正パラメータファイルを読み込む

地殻変動補正パラメータファイル を読み込む

def load_par(filename):
    par = pd.read_csv(filename, delim_whitespace=True, skiprows=15, index_col=0)
    return par

※モジュールのimport は割愛

補正値を計算

def semi_dyna_diff(par, lat, lon):
    phi_pitch = 2/3 / 8 / 2
    lamda_pitch = 1 / 8 / 2
    down  = np.floor(lat / phi_pitch  ) * phi_pitch
    up    = np.ceil( lat / phi_pitch  ) * phi_pitch
    left  = np.floor(lon / lamda_pitch) * lamda_pitch
    right = np.ceil( lon / lamda_pitch) * lamda_pitch
    
    z00 = latlon2mesh(down,  left) # 格子左下
    z01 = latlon2mesh(down, right) # 格子右下
    z10 = latlon2mesh(  up,  left) # 格子左上
    z11 = latlon2mesh(  up, right) # 格子右上
    
    p00 = par.loc[z00]
    p01 = par.loc[z01]
    p10 = par.loc[z10]
    p11 = par.loc[z11]

    t = (lat - down) / phi_pitch
    u = (lon - left) / lamda_pitch

    b00 = p00['dB(sec)'].to_numpy()
    b01 = p01['dB(sec)'].to_numpy()
    b10 = p10['dB(sec)'].to_numpy()
    b11 = p11['dB(sec)'].to_numpy()

    l00 = p00['dL(sec)'].to_numpy()
    l01 = p01['dL(sec)'].to_numpy()
    l10 = p10['dL(sec)'].to_numpy()
    l11 = p11['dL(sec)'].to_numpy()

    h00 = p00['dH(m)'].to_numpy()
    h01 = p01['dH(m)'].to_numpy()
    h10 = p10['dH(m)'].to_numpy()
    h11 = p11['dH(m)'].to_numpy()
    
    tu00 = (1 - t) * (1 - u)
    tu01 = (1 - t) * u
    tu10 = t * (1 - u)
    tu11 = t * u
    
    dB = tu00 * b00 + tu01 * b01 + tu10 * b10 + tu11 * b11
    dL = tu00 * l00 + tu01 * l01 + tu10 * l10 + tu11 * l11
    dH = tu00 * h00 + tu01 * h01 + tu10 * h10 + tu11 * h11
    
    return dB / 60 / 60, dL / 60 / 60, dH

セミダイナミック補正

def semi_dyna(par, lat, lon, alt=None, sokuchi=0):
    """
    sokuchi:補正方向  =0:元期→今期, =1:今期→元期
    """
    
    dB, dL, dH = semi_dyna_diff(par, lat, lon)
    if sokuchi == 1:
        # 今期→元期
        dB, dL, dH = -dB, -dL, -dH
    
    if alt is None:
        return lat + dB, lon + dL
    else:
        return lat + dB, lon + dL, alt + dH

とりあえず、見よう見まねで下記を計算。
いくつかサンプルでは同じになっていたけど。あってそう？

https://www.gsi.go.jp/sokuchikijun/semidyna.html
https://vldb.gsi.go.jp/sokuchi/surveycalc/semidyna/web/index.html