[Bug] HexagonLayer has a bug on tooltips

[danilo-css]

Description

When using "HexagonLayer" of Pydeck, tooltips always return "undefined" when you put in the tooltips a variable that is on the data, such as:

tooltip = {
    "html": "<b>{variable_onmydataframe}</b>",
}

The problem disappears if you change to "ColumnLayer", for example.

Flavors

• [ ] Script tag
• [ ] React
• [X] Python/Jupyter notebook
• [ ] MapboxOverlay
• [ ] GoogleMapsOverlay
• [ ] CartoLayer
• [ ] ArcGIS

Expected Behavior

Tooltips should return the variable you put in them, such as when you run "ColumnLayer":

Instead they return undefined if you run "HexagonLayer"

Steps to Reproduce

Sample code provided by TYL on this link of stackoverflow.

import pandas as pd
import pydeck as pdk

DATA_URL = "https://raw.githubusercontent.com/ajduberstein/geo_datasets/master/housing.csv"
df = pd.read_csv(DATA_URL)

view = pdk.data_utils.compute_view(df[["lng", "lat"]])
view.pitch = 75
view.bearing = 60

column_layer = pdk.Layer(
    "ColumnLayer",
    data=df,
    get_position=["lng", "lat"],
    get_elevation="price_per_unit_area",
    elevation_scale=100,
    radius=50,
    get_fill_color=["mrt_distance * 10", "mrt_distance", "mrt_distance * 10", 140],
    pickable=True,
    auto_highlight=True,
)

hexagon_layer = pdk.Layer(
    "HexagonLayer",
    data=df,
    get_position=["lng", "lat"],
    get_elevation="price_per_unit_area",
    elevation_scale=100,
    radius=50,
    get_fill_color=["mrt_distance * 10", "mrt_distance", "mrt_distance * 10", 140],
    pickable=True,
    auto_highlight=True,
)

tooltip = {
    "html": "<b>{mrt_distance}</b> meters away from an MRT station, costs <b>{price_per_unit_area}</b> NTD/sqm",
    "style": {"background": "grey", "color": "white", "font-family": '"Helvetica Neue", Arial', "z-index": "10000"},
}

r = pdk.Deck(
    column_layer,
    initial_view_state=view,
    tooltip=tooltip,
    map_provider="mapbox",
    map_style=pdk.map_styles.SATELLITE,
)

r2 = pdk.Deck(
    hexagon_layer,
    initial_view_state=view,
    tooltip=tooltip,
    map_provider="mapbox",
    map_style=pdk.map_styles.SATELLITE,
)

r.to_html("column_layer.html")
r2.to_html("hexagon_layer.html")

Environment

• Framework version: pydeck 0.8.0
• Browser: Microsoft Edge
• OS: Windows 10

Logs

None

[danilo-css]

I can confirm this same bug of "HexagonLayer" happens with "GridLayer"

[Pessimistress]

This is likely not a bug, but a missing feature.

HexagonLayer/GridLayer are aggregation layers, so each column you hover over is a "bin" that contains an array of rows from your original data. So what do you expect to see in the tooltip here - a list of values, their sum, or average? There isn't enough information about this field to make that decision.

[danilo-css]

@Pessimistress Thanks. I did not know that. It would be nice to have some indication of that on the Pydeck documentation.

To be honest, the ColumnLayer already does what I need, except the colors of the HexagonLayer, going from yellow to red, which are a nice aspect I can't reproduce on the ColumnLayer.

As for what I think would be best on the hexagon tooltip, a list of values would be my choice, since it works for variables which are not quantitative, such as strings or categorical.

[Jesus89]

Hi @danilo-css,

I will make a POC with your proposal and think about the API for aggregating values.