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ScatterplotLayer

Screenshot from Ookla example.

lonboard.ScatterplotLayer

Bases: BaseArrowLayer

The ScatterplotLayer renders circles at given coordinates.

Example:

From GeoPandas:

import geopandas as gpd
from lonboard import Map, ScatterplotLayer

# A GeoDataFrame with Point or MultiPoint geometries
gdf = gpd.GeoDataFrame()
layer = ScatterplotLayer.from_geopandas(
    gdf,
    get_fill_color=[255, 0, 0],
)
m = Map(layer)

From geoarrow-rust:

from geoarrow.rust.core import read_parquet
from lonboard import Map, ScatterplotLayer

# Example: A GeoParquet file with Point or MultiPoint geometries
table = read_parquet("path/to/file.parquet")
layer = ScatterplotLayer(
    table=table,
    get_fill_color=[255, 0, 0],
)
m = Map(layer)

antialiasing class-attribute instance-attribute 

antialiasing = tag(sync=True)

If True, circles are rendered with smoothed edges. If False, circles are rendered with rough edges. Antialiasing can cause artifacts on edges of overlapping circles.

  • Type: bool, optional
  • Default: True

auto_highlight class-attribute instance-attribute 

auto_highlight = tag(sync=True)

When true, the current object pointed to by the mouse pointer (when hovered over) is highlighted with highlightColor.

Requires pickable to be True.

  • Type: bool
  • Default: False

billboard class-attribute instance-attribute 

billboard = tag(sync=True)

If True, rendered circles always face the camera. If False circles face up (i.e. are parallel with the ground plane).

  • Type: bool, optional
  • Default: False

extensions class-attribute instance-attribute 

extensions = tag(sync=True, **widget_serialization)

A list of layer extension objects to add additional features to a layer.

filled class-attribute instance-attribute 

filled = tag(sync=True)

Draw the filled area of points.

  • Type: bool, optional
  • Default: True

get_fill_color class-attribute instance-attribute 

get_fill_color = ColorAccessor(None, allow_none=True)

The filled color of each object in the format of [r, g, b, [a]]. Each channel is a number between 0-255 and a is 255 if not supplied.

  • Type: ColorAccessor, optional
    • If a single list or tuple is provided, it is used as the filled color for all objects.
    • If a numpy or pyarrow array is provided, each value in the array will be used as the filled color for the object at the same row index.
  • Default: [0, 0, 0, 255].

get_line_color class-attribute instance-attribute 

get_line_color = ColorAccessor(None, allow_none=True)

The outline color of each object in the format of [r, g, b, [a]]. Each channel is a number between 0-255 and a is 255 if not supplied.

  • Type: ColorAccessor, optional
    • If a single list or tuple is provided, it is used as the outline color for all objects.
    • If a numpy or pyarrow array is provided, each value in the array will be used as the outline color for the object at the same row index.
  • Default: [0, 0, 0, 255].

get_line_width class-attribute instance-attribute 

get_line_width = FloatAccessor(None, allow_none=True)

The width of the outline of each object, in units specified by line_width_units (default 'meters').

  • Type: FloatAccessor, optional
    • If a number is provided, it is used as the outline width for all objects.
    • If an array is provided, each value in the array will be used as the outline width for the object at the same row index.
  • Default: 1.

get_radius class-attribute instance-attribute 

get_radius = FloatAccessor(None, allow_none=True)

The radius of each object, in units specified by radius_units (default 'meters').

  • Type: FloatAccessor, optional
    • If a number is provided, it is used as the radius for all objects.
    • If an array is provided, each value in the array will be used as the radius for the object at the same row index.
  • Default: 1.

highlight_color class-attribute instance-attribute 

highlight_color = VariableLengthTuple(
    Int(), default_value=None, minlen=3, maxlen=4
)

RGBA color to blend with the highlighted object (the hovered over object if auto_highlight=true). When the value is a 3 component (RGB) array, a default alpha of 255 is applied.

  • Type: List or Tuple of integers
  • Default: [0, 0, 128, 128]

line_width_max_pixels class-attribute instance-attribute 

line_width_max_pixels = tag(sync=True)

The maximum line width in pixels. This can be used to prevent the stroke from getting too thick when zoomed in.

  • Type: float, optional
  • Default: None

line_width_min_pixels class-attribute instance-attribute 

line_width_min_pixels = tag(sync=True)

The minimum line width in pixels. This can be used to prevent the stroke from getting too thin when zoomed out.

  • Type: float, optional
  • Default: 0

line_width_scale class-attribute instance-attribute 

line_width_scale = tag(sync=True)

A global line width multiplier for all points.

  • Type: float, optional
  • Default: 1

line_width_units class-attribute instance-attribute 

line_width_units = tag(sync=True)

The units of the line width, one of 'meters', 'common', and 'pixels'. See unit system.

  • Type: str, optional
  • Default: 'meters'

opacity class-attribute instance-attribute 

opacity = tag(sync=True)

The opacity of the layer.

  • Type: float. Must range between 0 and 1.
  • Default: 1

pickable class-attribute instance-attribute 

pickable = tag(sync=True)

Whether the layer responds to mouse pointer picking events.

This must be set to True for tooltips and other interactive elements to be available. This can also be used to only allow picking on specific layers within a map instance.

Note that picking has some performance overhead in rendering. To get the absolute best rendering performance with large data (at the cost of removing interactivity), set this to False.

  • Type: bool
  • Default: True

radius_max_pixels class-attribute instance-attribute 

radius_max_pixels = tag(sync=True)

The maximum radius in pixels. This can be used to prevent the circle from getting too big when zoomed in.

  • Type: float, optional
  • Default: None

radius_min_pixels class-attribute instance-attribute 

radius_min_pixels = tag(sync=True)

The minimum radius in pixels. This can be used to prevent the circle from getting too small when zoomed out.

  • Type: float, optional
  • Default: 0

radius_scale class-attribute instance-attribute 

radius_scale = tag(sync=True)

A global radius multiplier for all points.

  • Type: float, optional
  • Default: 1

radius_units class-attribute instance-attribute 

radius_units = tag(sync=True)

The units of the radius, one of 'meters', 'common', and 'pixels'. See unit system.

  • Type: str, optional
  • Default: 'meters'

selected_index class-attribute instance-attribute 

selected_index = tag(sync=True)

The positional index of the most-recently clicked on row of data.

You can use this to access the full row of data from a GeoDataFrame

gdf.iloc[layer.selected_index]

Setting a value here from Python will do nothing. This attribute only exists to be updated from JavaScript on a map click. Note that pickable must be True (the default) on this layer for the JavaScript onClick handler to work; if pickable is set to False, selected_index will never update.

Note that you can use observe to call a function whenever a new value is received from JavaScript. Refer here for an example.

stroked class-attribute instance-attribute 

stroked = tag(sync=True)

Draw the outline of points.

  • Type: bool, optional
  • Default: False

table class-attribute instance-attribute 

table = ArrowTableTrait(allowed_geometry_types={POINT, MULTIPOINT})

A GeoArrow table with a Point or MultiPoint column.

This is the fastest way to plot data from an existing GeoArrow source, such as geoarrow-rust or geoarrow-pyarrow.

If you have a GeoPandas GeoDataFrame, use from_geopandas instead.

visible class-attribute instance-attribute 

visible = tag(sync=True)

Whether the layer is visible.

Under most circumstances, using the visible attribute to control the visibility of layers is recommended over removing/adding the layer from the Map.layers list.

In particular, toggling the visible attribute will persist the layer on the JavaScript side, while removing/adding the layer from the Map.layers list will re-download and re-render from scratch.

  • Type: bool
  • Default: True

from_duckdb classmethod 

from_duckdb(
    sql: Union[str, DuckDBPyRelation],
    con: Optional[DuckDBPyConnection] = None,
    *,
    crs: Optional[Union[str, CRS]] = None,
    **kwargs: Unpack[ScatterplotLayerKwargs]
) -> Self

Construct a Layer from a duckdb-spatial query.

DuckDB Spatial does not currently expose coordinate reference system information, so the user must ensure that data has been reprojected to EPSG:4326 or pass in the existing CRS of the data in the crs keyword parameter.

Parameters:

  • sql (Union[str, DuckDBPyRelation]) –

    The SQL input to visualize. This can either be a string containing a SQL query or the output of the duckdb sql function.

  • con (Optional[DuckDBPyConnection], default: None ) –

    The current DuckDB connection. This is required when passing a str to the sql parameter or when using a non-global DuckDB connection. Defaults to None.

Other Parameters:

  • crs (Optional[Union[str, CRS]]) –

    The CRS of the input data. This can either be a string passed to pyproj.CRS.from_user_input or a pyproj.CRS object. Defaults to None.

Returns:

  • Self –

    A Layer with the initialized data.

from_geopandas classmethod 

from_geopandas(
    gdf: GeoDataFrame,
    *,
    auto_downcast: bool = True,
    **kwargs: Unpack[ScatterplotLayerKwargs]
) -> Self

Construct a Layer from a geopandas GeoDataFrame.

The GeoDataFrame will be reprojected to EPSG:4326 if it is not already in that coordinate system.

Parameters:

  • gdf (GeoDataFrame) –

    The GeoDataFrame to set on the layer.

Other Parameters:

Returns:

  • Self –

    A Layer with the initialized data.