SedonaSQL 构造函数使用说明

读取 ESRI Shapefile

函数说明: 读取Shapefile构建DataFrame对象

支持版本: v1.0.0

Spark SQL 举例说明:

var spatialRDD = new SpatialRDD[Geometry]
spatialRDD.rawSpatialRDD = ShapefileReader.readToGeometryRDD(sparkSession.sparkContext, shapefileInputLocation)
var rawSpatialDf = Adapter.toDf(spatialRDD,sparkSession)
rawSpatialDf.createOrReplaceTempView("rawSpatialDf")
var spatialDf = sparkSession.sql("""
          | ST_GeomFromWKT(rddshape), _c1, _c2
          | FROM rawSpatialDf
        """.stripMargin)
spatialDf.show()
spatialDf.printSchema()

!!!注意
文件扩展名 .shp, .shx, .dbf 必须小写. 例如:有一个 myShapefile 文件夹, 文件目录结构:

- shapefile1
- shapefile2
- myshapefile
- myshapefile.shp
- myshapefile.shx
- myshapefile.dbf
- myshapefile...

!!!注意
请确认必须使用 ST_GeomFromWKT 去实例化geometry几何列,否则在SedonaSQL将不能够使用几何属性

如果读取的文件包涵 non-ASCII 格式 需要设置编码格式
通过 sedona.global.charset 设置,在调用前 ShapefileReader.readToGeometryRDD.

举例:

System.setProperty("sedona.global.charset", "utf8")

ST_GeomFromGeoHash

函数说明: 通过geohash字符串创建Geometry几何,参数geohash长度

语法: ST_GeomFromGeoHash(geohash: string, precision: int)

支持版本: v1.1.1

Spark SQL 举例说明:

SELECT ST_GeomFromGeoHash('s00twy01mt', 4) AS geom

结果:

+--------------------------------------------------------------------------------------------------------------------+
|geom                                                                                                                |
+--------------------------------------------------------------------------------------------------------------------+
|POLYGON ((0.703125 0.87890625, 0.703125 1.0546875, 1.0546875 1.0546875, 1.0546875 0.87890625, 0.703125 0.87890625)) |
+--------------------------------------------------------------------------------------------------------------------+

ST_GeomFromGeoJSON

函数说明: 通过GeoJson创建Geometry几何

语法: ST_GeomFromGeoJSON (GeoJson:string)

支持版本: v1.0.0

Spark SQL 举例说明:

var polygonJsonDf = sparkSession.read.format("csv").option("delimiter","\t").option("header","false").load(geoJsonGeomInputLocation)
polygonJsonDf.createOrReplaceTempView("polygontable")
polygonJsonDf.show()
var polygonDf = sparkSession.sql(
        """
          | SELECT ST_GeomFromGeoJSON(polygontable._c0) AS countyshape
          | FROM polygontable
        """.stripMargin)
polygonDf.show()

!!!注意
SedonaSQL读取GeoJson的方式与SparkSql是有区别的

ST_GeomFromGML

函数说明: 通过GML创建Geometry几何.

语法: ST_GeomFromGML (gml:string)

支持版本: v1.3.0

Spark SQL 举例说明:

SELECT ST_GeomFromGML('-71.16028,42.258729 -71.160837,42.259112 -71.161143,42.25932') AS geometry

ST_GeomFromKML

函数说明: 通过KML创建Geometry.

语法: ST_GeomFromKML (kml:string)

支持版本: v1.3.0

Spark SQL 举例说明:

SELECT ST_GeomFromKML('-71.1663,42.2614 -71.1667,42.2616') AS geometry

ST_GeomFromText

函数说明: 通过Wkt创建Geometry几何,srid在不指定的情况下默认=0. 也可以通过 ST_GeomFromWKT

语法:
ST_GeomFromText (Wkt:string)
ST_GeomFromText (Wkt:string, srid:integer)

支持版本: v1.0.0

可选参数srid在 v1.3.1 版本加入

Spark SQL 举例说明:

SELECT ST_GeomFromText('POINT(40.7128 -74.0060)') AS geometry

ST_GeomFromWKB

函数说明: 通过WKB字符串或者WKB二进制格式创建Geometry几何

语法:
ST_GeomFromWKB (Wkb:string)
ST_GeomFromWKB (Wkb:binary)

支持版本: v1.0.0

Spark SQL 举例说明:

SELECT ST_GeomFromWKB(polygontable._c0) AS polygonshape
FROM polygontable

ST_GeomFromWKT

函数说明: 通过Wkt创建Geometry几何,srid在不指定的情况下默认=0.

语法:
ST_GeomFromWKT (Wkt:string)
ST_GeomFromWKT (Wkt:string, srid:integer)

支持版本: v1.0.0

可选参数srid在 v1.3.1 版本加入

Spark SQL 举例说明:

SELECT ST_GeomFromWKT(polygontable._c0) AS polygonshape
FROM polygontable

SELECT ST_GeomFromWKT('POINT(40.7128 -74.0060)') AS geometry

ST_LineFromText

函数说明: 通过WKT创建LineString

语法:
ST_LineFromText (Wkt:string)

支持版本: v1.2.1

Spark SQL 举例说明:

SELECT ST_LineFromText(linetable._c0) AS lineshape
FROM linetable

SELECT ST_LineFromText('Linestring(1 2, 3 4)') AS line

ST_LineStringFromText

函数说明: 通过Text创建LineString,并设置分隔符号

语法: ST_LineStringFromText (Text:string, Delimiter:char)

支持版本: v1.0.0

Spark SQL 举例说明:

SELECT ST_LineStringFromText(linestringtable._c0,',') AS linestringshape
FROM linestringtable

SELECT ST_LineStringFromText('-74.0428197,40.6867969,-74.0421975,40.6921336,-74.0508020,40.6912794', ',') AS linestringshape

ST_MLineFromText

函数说明: 通过Wkt构建多线MultiLineString. srid在不指定的情况下默认=0.

语法:
ST_MLineFromText (Wkt:string)
ST_MLineFromText (Wkt:string, srid:integer)

支持版本: v1.3.1

Spark SQL 举例说明:

SELECT ST_MLineFromText('MULTILINESTRING((1 2, 3 4), (4 5, 6 7))') AS multiLine;
SELECT ST_MLineFromText('MULTILINESTRING((1 2, 3 4), (4 5, 6 7))',4269) AS multiLine;

ST_MPolyFromText

函数说明: 通过Wkt构建MultiPolygon. srid在不指定的情况下默认=0.

语法:
ST_MPolyFromText (Wkt:string)
ST_MPolyFromText (Wkt:string, srid:integer)

支持版本: v1.3.1

Spark SQL 举例说明:

SELECT ST_MPolyFromText('MULTIPOLYGON(((-70.916 42.1002,-70.9468 42.0946,-70.9765 42.0872 )))') AS multiPolygon
SELECT ST_MPolyFromText('MULTIPOLYGON(((-70.916 42.1002,-70.9468 42.0946,-70.9765 42.0872 )))',4269) AS multiPolygon

ST_Point

函数说明: 通过X,Y创建Point

语法: ST_Point (X:decimal, Y:decimal)

支持版本: v1.0.0

从 v1.4.0 版本移除了可选参数 Z.
如果从老版本升级过来,请用ST_PointZ去创建3D points.

Spark SQL 举例说明:

SELECT ST_Point(CAST(pointtable._c0 AS Decimal(24,20)), CAST(pointtable._c1 AS Decimal(24,20))) AS pointshape
FROM pointtable

ST_PointZ

函数说明: 通过X,Y,Z创建Point,可选参数srid. srid在不指定的情况下默认=0.

语法: ST_PointZ (X:decimal, Y:decimal, Z:decimal)
语法: ST_PointZ (X:decimal, Y:decimal, Z:decimal, srid:integer)

支持版本: v1.4.0

Spark SQL 举例说明:

SELECT ST_PointZ(1.0, 2.0, 3.0) AS pointshape

ST_PointFromText

函数说明: 通过Text创建Point,参数分隔符

语法: ST_PointFromText (Text:string, Delimiter:char)

支持版本: v1.0.0

Spark SQL 举例说明:

SELECT ST_PointFromText(pointtable._c0,',') AS pointshape
FROM pointtable

SELECT ST_PointFromText('40.7128,-74.0060', ',') AS pointshape

ST_PolygonFromEnvelope

函数说明: 通过MinX, MinY, MaxX, MaxY创建Polygon.

语法: ST_PolygonFromEnvelope (MinX:decimal, MinY:decimal, MaxX:decimal, MaxY:decimal)

支持版本: v1.0.0

Spark SQL 举例说明:

SELECT *
FROM pointdf
WHERE ST_Contains(ST_PolygonFromEnvelope(1.0,100.0,1000.0,1100.0), pointdf.pointshape)

ST_PolygonFromText

函数说明: 通过Text创建Polygon,参数分隔符.路径(几何点)必须闭合

语法: ST_PolygonFromText (Text:string, Delimiter:char)

支持版本: v1.0.0

Spark SQL 举例说明:

SELECT ST_PolygonFromText(polygontable._c0,',') AS polygonshape
FROM polygontable

SELECT ST_PolygonFromText('-74.0428197,40.6867969,-74.0421975,40.6921336,-74.0508020,40.6912794,-74.0428197,40.6867969', ',') AS polygonshape