如何用geoalchemy2和postgresql插入几何学

Question

我试图将几何数据插入数据库，但它不起作用。我创建了一个几何模型类，但如果它是对的，我现在就不这样做了。

几何类：

from datetime import datetime

from sqlalchemy import and_
from sqlalchemy import Column
from sqlalchemy import create_engine
from sqlalchemy import DateTime
from sqlalchemy import Float
from sqlalchemy import ForeignKey
from sqlalchemy import Integer
from sqlalchemy import SMALLINT
from sqlalchemy import BIGINT
from sqlalchemy import String
from sqlalchemy import DateTime
from geoalchemy2 import Geometry as Geom
from sqlalchemy.orm import relationship
from sqlalchemy.orm import Session
from sqlalchemy.ext.declarative import declarative_base

Base = declarative_base()

class Geometry(Base):
    __tablename__ = "geometry"

    id = Column(Integer, primary_key=True)
    fill_color = Column(String(7))
    stroke_color = Column(String(7))
    geom = Column(Geom(geometry_type=None)) # here my Geometry column 
    type = Column(String(20))
    area = Column(BIGINT, nullable=False)
    lengh = Column(BIGINT, nullable=False)
    creation_date = Column(DateTime, nullable=False)
    stroke_width = Column(SMALLINT, nullable=False)
    tn = Column(Integer, nullable=False)
    vegetation_index = Column(Integer)

插入代码：

for index, line in data[['Shape_Area', 'Shape_Leng', 'TN', 
  'geometry']].iterrows():
  geometry = line['geometry']
  area = line['Shape_Area']
  lengh = line['Shape_Leng']
  tn = line['TN']
  now = datetime.now()
  
  geom = Geometry(geom='POLYGON((0 0,1 0,1 1,0 1,0 0))', 
    type=geometry.type, area=area, lengh=lengh, creation_date=now, tn=tn)

self._session.add(geom)
self._session.commit()

错误：

sqlalchemy.exc.ProgrammingError

sqlalchemy.exc.ProgrammingError: (psycopg2.errors.UndefinedFunction) function st_geomfromewkt(unknown) does not exist
LINE 1: ..._width, tn, vegetation_index) VALUES (NULL, NULL, ST_GeomFro...
                                                             ^
HINT:  No function matches the given name and argument types. You might need to add explicit type casts.

[SQL: INSERT INTO geometry (fill_color, stroke_color, geom, type, area, lengh, creation_date, stroke_width, tn, vegetation_index) VALUES (%(fill_color)s, %(stroke_color)s, ST_GeomFromEWKT(%(geom)s), %(type)s, %(area)s, %(lengh)s, %(creation_date)s, %(stroke_width)s, %(tn)s, %(vegetation_index)s) RETURNING geometry.id]
[parameters: {'fill_color': None, 'stroke_color': None, 'geom': 'POLYGON((0 0,1 0,1 1,0 1,0 0))', 'type': 'MultiPolygon', 'area': 699322.6710989687, 'lengh': 3855.587947253079, 'creation_date': datetime.datetime(2020, 11, 4, 17, 25, 37, 943407), 'stroke_width': None, 'tn': '000.000', 'vegetation_index': None}]
(Background on this error at: http://sqlalche.me/e/13/f405)

我想包括任何类型的几何，而不仅仅是多边形。

Answer 1

几何图形是列类型，请尝试另一个名称。

class myTableWithGeom(Base):

__tablename__ = "myTableWithGeom"

id = Column(Integer, primary_key=True)
fill_color = Column(String(7))
stroke_color = Column(String(7))
geom = Column(Geometry(geometry_type='POLYGON')) # here your Geometry column 
type = Column(String(20))
area = Column(BIGINT, nullable=False)
lengh = Column(BIGINT, nullable=False)
creation_date = Column(DateTime, nullable=False)
stroke_width = Column(SMALLINT, nullable=False)
tn = Column(Integer, nullable=False)
vegetation_index = Column(Integer)

geom_test = myTableWithGeom()

这里不需要实例化几何对象，只需

geom_test.geom = 'POLYGON((0 0,1 0,1 1,0 1,0 0))' 

然后可以添加和提交

self._session.add(geom)
self._session.commit()