在使用 Geomesa 和 Scala 时,我一直在尝试使用以下代码片段对 Spark Dataframe 中的 2 列进行编码,但我不断收到一个问题,Scala 似乎无法将返回的对象序列化为 Dataframe。使用 Postgres 和 PostGIS 时,生活很轻松 - 这是一个简单的问题,还是有更好的库可以处理来自包含双格式纬度和经度的 Spark Dataframe 的地理空间查询?
我在 SBT 中使用的版本是:
- 火花:2.3.0
- 斯卡拉:2.11.12
- 几何图形:2.2.1
- jst-*: 1.17.0-SNAPSHOT
线程“主”java.lang.UnsupportedOperationException 中的异常:未找到 org.locationtech.jts.geom.Point 的编码器
import org.apache.spark.sql.SparkSession
import org.locationtech.jts.geom.{Coordinate, GeometryFactory}
import org.apache.spark.sql.functions.col
import org.apache.spark.sql.types._
import org.locationtech.geomesa.spark.jts._
object GetRandomData {
def main(sysArgs: Array[String]) {
@transient val spark: SparkSession = {
SparkSession
.builder()
.config("spark.ui.enabled", "false")
.config("spark.serializer", "org.apache.spark.serializer.KryoSerializer")
.config("spark.kryoserializer.buffer.mb","24")
.appName("GetRandomData")
.master("local[*]")
.getOrCreate()
}
val sc = spark.sparkContext
sc.setLogLevel("ERROR")
import spark.sqlContext.implicits._
var coordinates = sc.parallelize(
List(
(35.40466, -80.905458),
(35.344079, -80.872267),
(35.139606, -80.840845),
(35.537786, -80.780051),
(35.525361, -83.031932),
(34.928323, -80.766732),
(35.533865, -82.72344),
(35.50997, -80.588572),
(35.286251, -83.150514),
(35.558519, -81.067069),
(35.569311, -80.916993),
(35.835867, -81.067904),
(35.221695, -82.662141)
)
).
toDS().
toDF("geo_lat", "geo_lng")
coordinates = coordinates.select(coordinates.columns.map(c => col(c).cast(DoubleType)) : _*)
coordinates.show()
val testing = coordinates.map(r => new GeometryFactory().createPoint(new Coordinate(3.4, 5.6)))
val coordinatesPointDf = coordinates.withColumn("point", st_makePoint(col("geo_lat"), col("geo_lng")))
}
}
例外是:
Exception in thread "main" java.lang.UnsupportedOperationException: No Encoder found for org.locationtech.jts.geom.Point
- root class: "org.locationtech.jts.geom.Point"
at org.apache.spark.sql.catalyst.ScalaReflection$$anonfun$org$apache$spark$sql$catalyst$ScalaReflection$$serializerFor$1.apply(ScalaReflection.scala:643)
at org.apache.spark.sql.catalyst.ScalaReflection$$anonfun$org$apache$spark$sql$catalyst$ScalaReflection$$serializerFor$1.apply(ScalaReflection.scala:445)
at scala.reflect.internal.tpe.TypeConstraints$UndoLog.undo(TypeConstraints.scala:56)
at org.apache.spark.sql.catalyst.ScalaReflection$class.cleanUpReflectionObjects(ScalaReflection.scala:824)
at org.apache.spark.sql.catalyst.ScalaReflection$.cleanUpReflectionObjects(ScalaReflection.scala:39)
at org.apache.spark.sql.catalyst.ScalaReflection$.org$apache$spark$sql$catalyst$ScalaReflection$$serializerFor(ScalaReflection.scala:445)
at org.apache.spark.sql.catalyst.ScalaReflection$.serializerFor(ScalaReflection.scala:434)
at org.apache.spark.sql.catalyst.encoders.ExpressionEncoder$.apply(ExpressionEncoder.scala:71)
at org.locationtech.geomesa.spark.jts.encoders.SpatialEncoders$class.jtsPointEncoder(SpatialEncoders.scala:21)
at org.locationtech.geomesa.spark.jts.package$.jtsPointEncoder(package.scala:17)
at GetRandomData$.main(Main.scala:50)
at GetRandomData.main(Main.scala)