对网格文件采样

利用 pygmt.grdtrack() 对网格文件进行采样。

Out:

gmtwhich [NOTICE]: Remote data courtesy of GMT data server OCEANIA [https://oceania.generic-mapping-tools.org]
gmtwhich [NOTICE]: Earth Relief at 1x1 arc degrees from Gaussian Cartesian filtering (111 km fullwidth) of SRTM15+V2.1 [Tozer et al., 2019].
gmtwhich [NOTICE]:   -> Download grid file [115K]: earth_relief_01d_p.grd
gmtwhich [NOTICE]:   -> Download cache file: @ridge.txt

<IPython.core.display.Image object>

import pygmt

# 从 GMT 服务器加载地形数据
grid = pygmt.datasets.load_earth_relief()
# 从 GMT 服务器加载洋中脊数据
points = pygmt.datasets.load_ocean_ridge_points()
# 沿轨迹点对洋中脊测深
track = pygmt.grdtrack(points=points, grid=grid, newcolname="bathymetry")

fig = pygmt.Figure()
fig.basemap(region="g", frame=True, projection="Cyl_stere/150/-20/15c")
fig.grdimage(grid=grid, cmap="gray")
fig.coast(land="#666666")

fig.plot(
    x=track.longitude,
    y=track.latitude,
    style="c0.15c",
    cmap="terra",
    color=(track.bathymetry - track.bathymetry.mean()) / track.bathymetry.std(),
)
fig.show()