Bases: BaseArrowLayer
The PathLayer
renders lists of coordinate points as extruded polylines with mitering.
Example:
From GeoPandas:
import geopandas as gpd
from lonboard import Map, PathLayer
# A GeoDataFrame with LineString or MultiLineString geometries
gdf = gpd.GeoDataFrame()
layer = PathLayer.from_geopandas(
gdf,
get_color=[255, 0, 0],
width_min_pixels=2,
)
m = Map(layer)
From geoarrow-rust:
from geoarrow.rust.io import read_parquet
from lonboard import Map, PathLayer
# Example: A GeoParquet file with LineString or MultiLineString geometries
table = read_parquet("path/to/file.parquet")
layer = PathLayer(
table=table,
get_color=[255, 0, 0],
width_min_pixels=2,
)
m = Map(layer)
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
.
bool
False
class-attribute
instance-attribute
¶
billboard = tag(sync=True)
If True
, extrude the path in screen space (width always faces the camera). If False
, the width always faces up.
bool
, optionalFalse
class-attribute
instance-attribute
¶
cap_rounded = tag(sync=True)
Type of caps. If True
, draw round caps. Otherwise draw square caps.
bool
, optionalFalse
class-attribute
instance-attribute
¶
extensions = tag(sync=True, **widget_serialization)
A list of layer extension objects to add additional features to a layer.
get_colorclass-attribute
instance-attribute
¶
The color of each path in the format of [r, g, b, [a]]
. Each channel is a number between 0-255 and a
is 255 if not supplied.
list
or tuple
is provided, it is used as the color for all paths.[0, 0, 0, 255]
.class-attribute
instance-attribute
¶
The width of each path, in units specified by width_units
(default 'meters'
).
1
.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.
[0, 0, 128, 128]
class-attribute
instance-attribute
¶
joint_rounded = tag(sync=True)
Type of joint. If True
, draw round joints. Otherwise draw miter joints.
bool
, optionalFalse
class-attribute
instance-attribute
¶
miter_limit = tag(sync=True)
The maximum extent of a joint in ratio to the stroke width. Only works if jointRounded
is False
.
float
, optional4
class-attribute
instance-attribute
¶
The opacity of the layer.
float
. Must range between 0 and 1.1
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
.
bool
True
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.
class-attribute
instance-attribute
¶
table = ArrowTableTrait(allowed_geometry_types={LINESTRING, MULTILINESTRING})
A GeoArrow table with a LineString or MultiLineString 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.
class-attribute
instance-attribute
¶
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.
bool
True
class-attribute
instance-attribute
¶
width_max_pixels = tag(sync=True)
The maximum path width in pixels. This prop can be used to prevent the path from getting too thick when zoomed in.
float
, optionalNone
class-attribute
instance-attribute
¶
width_min_pixels = tag(sync=True)
The minimum path width in pixels. This prop can be used to prevent the path from getting too thin when zoomed out.
float
, optional0
class-attribute
instance-attribute
¶
width_scale = tag(sync=True)
The path width multiplier that multiplied to all paths.
float
, optional1
class-attribute
instance-attribute
¶
width_units = tag(sync=True)
The units of the line width, one of 'meters'
, 'common'
, and 'pixels'
. See unit system.
str
, optional'meters'
__init__(
table: ArrowStreamExportable,
*,
_rows_per_chunk: int | None = None,
**kwargs: Unpack[PathLayerKwargs]
) -> None
Construct a Layer from a GeoArrow table.
This accepts Arrow data from any library implementing the Arrow PyCapsule Interface, including pyarrow, arro3, DuckDB, and others.
The geometry column will be reprojected to EPSG:4326
if it is not already in that coordinate system.
Parameters:
table
(ArrowStreamExportable
) –
An Arrow table or stream object from a library implementing the [Arrow PyCapsule Interface]. This object must contain a column with a geometry type that has the geoarrow
extension metadata.
Other Parameters:
kwargs
(Unpack[BaseLayerKwargs]
) –
parameters passed on to __init__
Returns:
None
–
A Layer with the initialized data.
classmethod
¶
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
(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
(DuckDBPyConnection | None
, default: None
) –
The current DuckDB connection. This is required when passing a str
to the sql
parameter.
Other Parameters:
crs
(str | CRS | None
) –
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.
kwargs
(Unpack[BaseLayerKwargs]
) –
parameters passed on to __init__
Returns:
Self
–
A Layer with the initialized data.
classmethod
¶
from_geopandas(
gdf: GeoDataFrame,
*,
auto_downcast: bool = True,
**kwargs: Unpack[PathLayerKwargs]
) -> 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:
auto_downcast
(bool
) –
If True
, automatically downcast to smaller-size data types if possible without loss of precision. This calls pandas.DataFrame.convert_dtypes and pandas.to_numeric under the hood.
kwargs
(Unpack[BaseLayerKwargs]
) –
parameters passed on to __init__
Returns:
Self
–
A Layer with the initialized data.
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