与GeoAlchemy示例代码的瓶 [英] Flask with GeoAlchemy sample code
本文介绍了与GeoAlchemy示例代码的瓶的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
from app import db
from geoalchemy2.types import几何
class Point(db .Model):
$ bb代表x / y坐标位置。
__tablename__ ='point'
id = db .Column(db.Integer,primary_key = True)
geom = db.Column(Geometry(geometry_type ='POINT',srid = 4326))
示例查询:
from geoalchemy2.elements import WKTElement
从应用程序导入模型
def get_nearest(lat,lon):
#查找输入坐标的最近点
#将输入坐标转换为WKT点并查询最近格式(lon,lat),srid = 4326)
返回models.Point.query.order_by(models.Point.geom 。 distance_box(pt))。first()
将结果转换为x和y坐标转换为GeoJSON并提取坐标):
将geoalchemy2.functions作为func
导入json
import db
def point_geom_to_xy(pt):
#从点几何提取x和y坐标
geom_json = json.loads(db.session.scalar(func.ST_AsGeoJSON pt.geom)))
return geom_json ['coordinates']
Can anyone provide any sample code for Flask with GeoAlchemy?
解决方案
Using SQLAlchemy 0.8, Flask-SQLAlchemy and Geoalchemy 2:
from app import db
from geoalchemy2.types import Geometry
class Point(db.Model):
"""represents an x/y coordinate location."""
__tablename__ = 'point'
id = db.Column(db.Integer, primary_key=True)
geom = db.Column(Geometry(geometry_type='POINT', srid=4326))
Sample query:
from geoalchemy2.elements import WKTElement
from app import models
def get_nearest(lat, lon):
# find the nearest point to the input coordinates
# convert the input coordinates to a WKT point and query for nearest point
pt = WKTElement('POINT({0} {1})'.format(lon, lat), srid=4326)
return models.Point.query.order_by(models.Point.geom.distance_box(pt)).first()
One way of converting the result to x and y coordinates (convert to GeoJSON and extract coordinates):
import geoalchemy2.functions as func
import json
from app import db
def point_geom_to_xy(pt):
# extract x and y coordinates from a point geometry
geom_json = json.loads(db.session.scalar(func.ST_AsGeoJSON(pt.geom)))
return geom_json['coordinates']
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