在ogr或geopandas python中的shapefile中创建FID列

Question

我需要形状文件中FID列的信息。不知何故，在加载shapefile时，该列并没有“显示”。我需要该专栏的信息，因为我需要说：

^{tb1}$

我需要知道哪些FID属于ids X、Y、Z等。我在geopandas中尝试了以下方法。有没有更有效的方法使用osgeo的geopandas或OGR？谢谢

import os
import geopandas as gpd
import numpy as np
from osgeo import ogr

# open the training data
train_cl_fn = os.path.join(src, "train.shp")

# read the column "id" that already exists. This id column says that feature X belongs to id Y
X_train_G = gpd.read_file(train_cl_fn)
class_ids = X_train_G["id"].unique()
print('class ids: ', class_ids)

# I create an empty array for the fids
class_fids = np.array([])
print('class labels: ', class_fids)

# add "fidl" column, using "id" and the empty array
# FID and fid are the same, therefore "fidl"
X_train_G['fidl'] = X_train_G['id'].map(dict(zip(class_ids, class_fids)))
print(X_train_G.head())

# export: rewrite file
X_train_G.to_file(os.path.join(src, "train.shp"))

# open the SAME file again, this time in ogr
train_cl_fn = os.path.join(src, "train.shp")
driver = ogr.GetDriverByName('ESRI Shapefile')
train_ds = driver.Open(train_cl_fn, 1) # 0 means read-only. 1 means writeable.
layer = train_ds.GetLayer()

for Ft in layer:
    ThisID = int(Ft.GetFID())
    #print('id is {}'.format(ThisID))
    Ft.SetField('fidl',ThisID)          # Write the FID to the fidl field
    layer.SetFeature(Ft)              # update the feature
dataSource = None  # save/rewrite file with fid info in the fidl column

Answer 1

好的。。。读了一点之后，我发现了一种更有效的方法

import os
from osgeo import ogr

src = "C:/path/"

#### Read SHP and create X_train_x segments array ####
# open training data
train_cl_fn = os.path.join(src, "train.shp")
driver = ogr.GetDriverByName('ESRI Shapefile')
train_ds = driver.Open(train_cl_fn, 1) # 0 means read-only. 1 means writeable.
layer = train_ds.GetLayer()

fieldDefn = ogr.FieldDefn('fidl', ogr.OFTReal) 
fieldDefn.SetWidth(14) 
fieldDefn.SetPrecision(6)
layer.CreateField(fieldDefn)

for Ft in layer:
    ThisID = int(Ft.GetFID())
    #print('id is {}'.format(ThisID))
    Ft.SetField('fidl',ThisID)          # Write the FID to the fidl field
    layer.SetFeature(Ft)              # update the feature
dataSource = None  

你知道更好的方法吗