Being able to produce a heatmap even with only a geometric field

[aborruso]

Hi,
if in my below code I remove the id_bene field and thus only one geom field is present

sql = """
CREATE TABLE rides AS
SELECT
  id_bene,ST_Point(longitudine, latitudine) as geom
FROM
  parquet_scan('../data/beni_immobili_pubblici_geo.parquet');
"""

con.execute(sql)

con.table("rides")

layer = HeatmapLayer.from_duckdb(con.table("rides"), con)

m = Map(layer)
m

I have these errors

AttributeError                            Traceback (most recent call last)
Cell In[11], line 24
     20 con.execute(sql)
     22 con.table("rides")
---> 24 layer = HeatmapLayer.from_duckdb(con.table("rides"), con)
     26 m = Map(layer)
     27 m

File ~/.local/lib/python3.11/site-packages/lonboard/_layer.py:1689, in HeatmapLayer.from_duckdb(cls, sql, con, crs, **kwargs)
   1680 @classmethod
   1681 def from_duckdb(
   1682     cls,
   (...)
   1687     **kwargs: Unpack[HeatmapLayerKwargs],
   1688 ) -> Self:
-> 1689     return super().from_duckdb(sql=sql, con=con, crs=crs, **kwargs)

File ~/.local/lib/python3.11/site-packages/lonboard/_layer.py:372, in BaseArrowLayer.from_duckdb(cls, sql, con, crs, **kwargs)
    370     table = _from_duckdb(rel, con=con, crs=crs)
    371 else:
--> 372     table = _from_duckdb(sql, con=con, crs=crs)
    374 return cls(table=table, **kwargs)

File ~/.local/lib/python3.11/site-packages/lonboard/_geoarrow/_duckdb.py:57, in from_duckdb(rel, con, crs)
...
     95     geom_col_name = rel.columns[geom_col_idx]
     97     # A poor-man's string interpolation check
     98     # We can't pass in SQL-templated strings for the column name

AttributeError: 'NoneType' object has no attribute 'arrow'

Why is it not possible to have a heatmap from only a geom field?

If it were possible, I would enable it.

Thank you for this great product

[kylebarron]

This is probably a general bug with DuckDB import when you have no attribute columns. Does it work fine if you have another column in your table?

[kylebarron]

@aborruso what version of DuckDB do you have installed? I can't reproduce this, either with 0.10.3 or with 1.0.0.

[kylebarron]

I added a test case in #623

[aborruso]

@aborruso what version of DuckDB do you have installed? I can't reproduce this, either with 0.10.3 or with 1.0.0.

Thank you @kylebarron this in my environment:

DuckDB version: 1.0.0
Lonboard version: 0.9.3
Python version: 3.11.2 (main, Mar 13 2023, 12:18:29) [GCC 12.2.0]
Jupyter Notebook version: 7.0.4

This is the input file I use in the below code: https://github.com/aborruso/beni_immobili_pubblica_amministrazione/blob/main/data/beni_immobili_pubblici_geo.parquet

from lonboard import HeatmapLayer, Map
import duckdb

# Initialize DuckDB connection
con = duckdb.connect()

# Load spatial extension
duckdb.install_extension("spatial", connection=con)
duckdb.load_extension("spatial", connection=con)

# Esegui la query per creare la tabella immobili
sql = """
SELECT
  ST_GeomFromWKB(geometry) as geom
FROM
  '../data/beni_immobili_pubblici_geo.parquet' limit 1000;
"""

query = con.sql(sql)

layer = HeatmapLayer.from_duckdb(query, con)
m = Map(layer)
m

The error

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
Cell In[6], line 21
     12 sql = """
     13 SELECT
     14   ST_GeomFromWKB(geometry) as geom
     15 FROM
     16   '../data/beni_immobili_pubblici_geo.parquet' limit 1000;
     17 """
     19 query = con.sql(sql)
---> 21 layer = HeatmapLayer.from_duckdb(query, con)
     22 m = Map(layer)
     23 m

File ~/.local/lib/python3.11/site-packages/lonboard/_layer.py:1689, in HeatmapLayer.from_duckdb(cls, sql, con, crs, **kwargs)
   1680 @classmethod
   1681 def from_duckdb(
   1682     cls,
   (...)
   1687     **kwargs: Unpack[HeatmapLayerKwargs],
   1688 ) -> Self:
-> 1689     return super().from_duckdb(sql=sql, con=con, crs=crs, **kwargs)

File ~/.local/lib/python3.11/site-packages/lonboard/_layer.py:372, in BaseArrowLayer.from_duckdb(cls, sql, con, crs, **kwargs)
    370     table = _from_duckdb(rel, con=con, crs=crs)
...
     95     geom_col_name = rel.columns[geom_col_idx]
     97     # A poor-man's string interpolation check
     98     # We can't pass in SQL-templated strings for the column name

AttributeError: 'NoneType' object has no attribute 'arrow'

Thank you

[kylebarron]

Should be fixed now in #625

[aborruso]

Thank you very much @kylebarron !!