几何图形未被识别为 Find_SRID 的参数

Question

在下面发布的代码中，我想找到一个几何体的 SRID。我将几何作为参数传递。问题是当我运行代码时，我收到：

psycopg2.errors.SyntaxError: FEHLER:  Syntaxfehler bei »{«
LINE 3:             Find_SRID({'coordinates': [[[747588.406469401...
                             ^

为了修复它，我将 geometry 参数包含在单个 qoutes 之间，如下所示：

            ST_GeomFromJSON('{geometry}') As geomertySRID

但随后我收到以下错误：

psycopg2.errors.SyntaxError: FEHLER:  Syntaxfehler bei »coordinates«
LINE 3:             Find_SRID('{'coordinates': [[[747588.40646940...
                                ^

请告诉我如何修复此错误

代码:

def executeForFindSRID(self,geometry):
    print(geometry)        
    query="""
    SELECT
        ST_GeomFromGeoJSON({geometry}) As geomertySRID       
    """.format(geometry=geometry)
    data = self.connection.query(query,[])
    # print(data)        
    return data

几何

这是我想找到它的 SRID 的几何图形`

DEBUG:root:responseParameters['treatmentAsJSONInEPSG25832']: {'coordinates': [[[747588.4064694013, 6643569.636689969], [747597.3898909885, 6643584.395168291], [747581.3480667257, 6643607.880399012], [747574.9313370206, 6643609.292079547], [747563.5095581454, 6643597.870300672], [747556.9644938463, 6643584.780172074], [747562.6112159868, 6643575.668415893], [747577.2413597145, 6643570.278362939], [747588.4064694013, 6643569.636689969]]], 'type': 'Polygon'}
{'coordinates': [[[747588.4064694013, 6643569.636689969], [747597.3898909885, 6643584.395168291], [747581.3480667257, 6643607.880399012], [747574.9313370206, 6643609.292079547], [747563.5095581454, 6643597.870300672], [747556.9644938463, 6643584.780172074], [747562.6112159868, 6643575.668415893], [747577.2413597145, 6643570.278362939], [747588.4064694013, 6643569.636689969]]], 'type': 'Polygon'}

Answer 1

函数Find_SRID需要三个参数，即架构、table名称和几何列，例如：

SELECT Find_SRID('public','mytable','geom');

您也可以尝试函数 ST_SRID，它从给定的几何图形中提取 SRS：

SELECT ST_SRID(geom) FROM mytable;

如果您的几何没有声明 SRS，函数 ST_SRID 将 return 归零，因为 PostGIS 无法猜测 SRS。通常我们假设没有显式 SRS 的几何被编码为 WGS84 (EPSG:4326). As a matter of fact, WGS84 is the expected SRS in the GeoJSON Specification:

The coordinate reference system for all GeoJSON coordinates is a geographic coordinate reference system, using the World Geodetic System 1984 (WGS 84) [WGS84] datum, with longitude and latitude units of decimal degrees. This is equivalent to the coordinate reference system identified by the Open Geospatial Consortium (OGC) URN urn:ogc:def:crs:OGC::CRS84.

演示：db<>fiddle

几何图形未被识别为 Find_SRID 的参数

geometry is not recognized as parameter to Find_SRID

python

postgresql

postgis