ST_CentroidReturns the geometric center of a geometry ST_PointOnSurface(g1) Computes a point guaranteed to lie in a polygon, or on a geometry 例如,求Financial District社区的质心: SELECTST_Centroid(geom), ST_PointOnSurface(geom) FROMnyc_neighborhoods WHEREname='Financial District'; 2.2 缓冲区 ...
可以通过SQL语句创建这些空间数据对象。使用ST_MakePoint、ST_MakeLine、ST_MakePolygon等函数,可以创建对应的空间数据。这些数据将成为可视化的基础。 CREATE TABLE cities ( id SERIAL PRIMARY KEY, name VARCHAR(50), geom GEOMETRY(Point, 4326) ); INSERT INTO cities (name, geom) VALUES ('San Francisco', ...
【postgis】函数记录一丢丢-st_simplify、ST_SimplifyPreserveTopology,程序员大本营,技术文章内容聚合第一站。
connect( host = 'localhost', port = '5432', dbname = 'chap2', user = 'postgres', password = '123456' ) sqlCmd = conn.cursor() # 插入一行数据 strsql1 = '''Insert into point_data(id,name,shape) Values('06','zzzl',ST_GeometryFromText('Point(105 30)', 4490))''' sqlCmd.ex...
使用ST_LineSubstring提取向前和向后的线段部分: sql WITH center_location AS ( SELECT ST_LineLocatePoint(line_geom, point_geom) AS fraction FROM ( SELECT ST_GeomFromText('LINESTRING(0 0, 10 0)') AS line_geom, ST_GeomFromText('POINT(5 0)') AS point_geom ) AS subquery ), segment_...
cursor.execute('update gps_track set geometry = ST_SetSRID(geometry,4326)') 查询是否上传成功: # Retrieve the table contents and print it cursor.execute('SELECT * FROM gps_track') forrowincursor: print(row[0]) 关闭连接: # Disconnect from the database ...
st_asgeojson(geom) as geomJson "+" from ( with ynarea as ( select * from biz_area where province_name = #{province_name} ) "+" select st_distance(cinfo.geom::geography, ynarea.geom ::geography) dist,ynarea.* "+" from biz_world_country cinfo,ynarea where short_chinese_name =...
坐标值,则ST_Equals返回1 或 t (TRUE)。办公楼的第一层和第二层可具有相同的x,y坐标,因此这两层的几何相等。ST_Equals 还可识别是否错误地将两个要素中的一个放置到了... * * * 模式矩阵示例 简而言之,如果两个几何的内部相交,且a的内部和边界与b的外部不相交,则ST_Within谓词返回TRUE。所有其他条件...
st_x ( ( mic ).center ) lon, st_y ( ( mic ).center ) lat, st_asgeojson ( T.geom ) geomJson FROM biz_province T, ST_MaximumInscribedCircle ( geom ) AS mic WHERE = 1733467199265333250; 1. 2. 3. 4. 5. 6. 7. 8.
查询省会城市与各地市的距离,我们使用st_distance方法,关键的SQL语句如下所示: WITH Ta AS ( SELECT t.*, p.code FROM biz_province p JOIN biz_geographic_name t ON _st_contains(p.geom, t.geom) WHERE p.code = '430000' AND t.classz = 'AD' AND t.bz = '省会城市' ...