Python: Drop Pandas row if function returns false, utilizing is _land check through Cartopy

Question

我想根据函数 returns 是否为真来删除一行，该函数检查纬度和经度值是否在陆地上。我想删除 lat/long returns 错误的行。

这是我目前所拥有的，但我卡住了：

def LAND_SHAPE_READER():
    land_shp_fname = shpreader.natural_earth(resolution='10m',
                                             category='physical', 
name='land')

    land_geom = unary_union(list(shpreader.Reader(land_shp_fname).geometries()))
    land = prep(land_geom)

def IS_LAND(x, y):
    return land.contains(sgeom.Point(x, y))

def MAP_PLOT_CHECK():
    if IS_LAND(df['Longitude'], df['Latitude']):
        return
    else:  
        #drop row here

Answer 1

我认为最安全的方法是创建一个新列来存储您的 IS_LAND 值。

# Apply this function to every row, where x is the row
# Save the True/False return value as a column
df['IS_LAND_RETURN'] = df.apply(lambda x: IS_LAND(x['Longitude'], x['Latitude']), axis=1)

之后过滤就很简单了：

# Select df rows where IS_LAND_RETURN is true
land_only = df[df['IS_LAND_RETURN']]

Python: Drop Pandas row if function returns false, utilizing is _land check through Cartopy

Python: Drop Pandas row if function returns false, utilizing is _land check through Cartopy

python

python-3.x

pandas

cartopy