如何解决Spark DataFrame调用H3几何生成函数的异常问题？

我有一个包含H3六边形ID的Spark DataFrame，想要获取对应的多边形几何信息，但调用函数时出现异常：

1. 第一次尝试代码：

from pyspark.sql import SparkSession
from pyspark.sql.functions import col, expr
from pyspark.databricks.sql.functions import *

from mosaic import enable_mosaic
enable_mosaic(spark, dbutils)

# 创建Spark会话
spark = SparkSession.builder.appName("Mosaic").getOrCreate()

# 创建含H3 ID的DataFrame
df = spark.createDataFrame([
    (1, "87422c2a9ffffff"),
    (2, "87422c2a9000000"),
    (3, "87422c2a8ffffff")
], ("id", "h3hex_id"))

sdf2 = df.withColumn("geometry", h3_boundaryaswkt(col("h3hex_id")))
sdf2.sample(fraction=0.1).show()

报错：

AnalysisException: [H3_NOT_ENABLED] h3_boundaryaswkt is disabled or unsupported. Consider enabling Photon or switch to a tier that supports H3 expressions;

2. 改用Mosaic的grid_boundary函数：

sdf2 = df.withColumn("geometry", grid_boundary(col("h3hex_id"), format_name="WKT"))
sdf2.sample(fraction=0.1).show()

报错：

AnalysisException: [UNRESOLVED_COLUMN.WITH_SUGGESTION] A column or function parameter with name WKT cannot be resolved. Did you mean one of the following? ..

已在集群安装databricks-mosaic 0.3.10，请问如何解决？

1. 修复Spark会话初始化顺序 #

代码中先调用enable_mosaic(spark, dbutils)但未创建spark会话，导致Mosaic未正确注册函数。必须先创建Spark会话，再启用Mosaic。

2. 正确使用Mosaic的H3边界函数 #

Mosaic提供两种可靠方式获取H3多边形WKT：

方式一：h3_boundary + st_aswkt组合

h3_boundary返回二进制几何对象，需用st_aswkt转换为WKT格式：

from pyspark.sql import SparkSession
from pyspark.sql.functions import col
from mosaic import enable_mosaic
from mosaic.functions import h3_boundary, st_aswkt

# 先创建Spark会话
spark = SparkSession.builder.appName("Mosaic").getOrCreate()
# 再启用Mosaic
enable_mosaic(spark, dbutils)

# 创建DataFrame
df = spark.createDataFrame([
    (1, "87422c2a9ffffff"),
    (2, "87422c2a9000000"),
    (3, "87422c2a8ffffff")
], ("id", "h3hex_id"))

# 生成WKT格式的多边形
sdf2 = df.withColumn("geometry", st_aswkt(h3_boundary(col("h3hex_id"))))
sdf2.show(truncate=False)

方式二：正确使用grid_boundary参数

grid_boundary的格式参数需用字符串字面量（用单引号包裹），同时要指定网格类型为H3：

from pyspark.sql import SparkSession
from pyspark.sql.functions import col
from mosaic import enable_mosaic
from mosaic.functions import grid_boundary

spark = SparkSession.builder.appName("Mosaic").getOrCreate()
enable_mosaic(spark, dbutils)

df = spark.createDataFrame([
    (1, "87422c2a9ffffff"),
    (2, "87422c2a9000000"),
    (3, "87422c2a8ffffff")
], ("id", "h3hex_id"))

# 指定gridType为H3，format_name用单引号包裹
sdf2 = df.withColumn("geometry", grid_boundary(col("h3hex_id"), gridType="H3", format_name="'WKT'"))
sdf2.show(truncate=False)

3. 避免混用Databricks原生H3函数 #

报错中的h3_boundaryaswkt是Databricks原生H3函数，需集群启用Photon或对应付费Tier支持。既然已安装Mosaic，直接使用其提供的函数即可，无需依赖原生H3功能。

内容的提问来源于stack exchange，提问作者kms