Simple arrow (vector/quiver) icon for folium#

This package provides simple arrow (vector/quiver) icon for the folium package.

The arrow (vector/quiver) icon is independent of zoom level, its size does not change as zoom level changes. It is useful for displaying vector field.

You can install folium-arrow-icon from PyPI:

pip install folium-arrow-icon

This packages is released under MIT licence.

See Sample Code for example.

Module contents#

Simple arrow (vector/quiver) icon for folium.

class folium_arrow_icon.ArrowIcon(length: int | float, angle: int | float, head: ArrowIconHead = ArrowIconHead(width=8, length=10), body: ArrowIconBody = ArrowIconBody(width=2), color: str = 'black', border_width: int | float = 0, border_color: str | None = None, anchor: Literal['tail', 'mid', 'head'] = 'tail', popup_anchor: tuple[int, int] | None = None, class_name: str = 'empty')#

Bases: DivIcon

Simple arrow (vector/quiver) Icon.

Parameters:

length – the length of the vector which satisfies 0 <=.
angle – the angle of the vector in radian, it starts from the positive latidude axis and goes clockwise (Left-Handed System).
head – the head metric, defraulting ArrowIconHead(width=8, length=10).
body – the body metric, defraulting ArrowIconBody(width=2).
color – the color of the vector, supporting any CSS color propery.
border_width – the border width.
border_color – the border color.
anchor – the anchor of the vector.
popup_anchor – it passes to the folium.DivIcon constructor.
class_name – it passes to the folium.DivIcon constructor.

Examples

A marker with a vector icon of which length is 100px and directing positive longitude.

>>> folium.Marker(
...     (40.78322, -73.96551),
...     icon=ArrowIcon(100, math.pi / 2),
... )

More customized example;

>>> folium.Marker(
...     (40.78322, -73.96551),
...     icon=ArrowIcon(
...         100, math.pi
...         head=ArrowIconHead(width=10, length=20),
...         body=ArrowIconBody(width=5),
...         color="hsl(30deg, 100%, 50%)",
...         border_width=1,
...         border_color="red",
...         anchor="mid"
...     )
... )

classmethod from_comp(components: Sequence[int | float], head: ArrowIconHead = ArrowIconHead(width=8, length=10), body: ArrowIconBody = ArrowIconBody(width=2), color: str = 'black', border_width: int | float = 0, border_color: str | None = None, anchor: Literal['tail', 'mid', 'head'] = 'tail', popup_anchor: tuple[int, int] | None = None, class_name: str = 'empty')#

Makes a ArrowIcon from components of latitude and longitude direction.

Parameters:

components – the components vector, latitude and longitude direction.
head – the head metric, defraulting ArrowIconHead(width=8, length=10).
body – the body metric, defraulting ArrowIconBody(width=2).
color – the color of the vector, supporting any CSS color propery.
border_width – the border width.
border_color – the border color.
anchor – the anchor of the vector.
popup_anchor – it passes to the folium.DivIcon constructor.
class_name – it passes to the folium.DivIcon constructor.

Returns:

a ArrowIcon obj

Examples

A marker with a vector icon of which latitude compnent is 100 px and longitude is 50px.

>>> folium.Marker(
...     (40.78322, -73.96551),
...     icon=ArrowIcon.from_comp((100, 50)),
... )

More customized example;

>>> folium.Marker(
...     (40.78322, -73.96551),
...     icon=ArrowIcon.from_comp(
...         (100, 50)
...         head=ArrowIconHead(width=10, length=20),
...         body=ArrowrIconBody(width=5),
...         color="hsl(30deg, 100%, 50%)",
...         border_width=1,
...         border_color="red",
...         anchor="mid"
...     ),
... )

class folium_arrow_icon.ArrowIconHead(width: int | float = 8, length: int | float = 10)#

Bases: object

Metric of head.

width: int | float = 8#: Width of head

length: int | float = 10#: Width of length

class folium_arrow_icon.ArrowIconBody(width: int | float = 2)#

Bases: object

Metric of body.

width: int | float = 2#: Width of boby

Sample Code#

import math

import folium
from folium_arrow_icon import ArrowIcon

By length and angle#

m = folium.Map(
    location=[40.78322, -73.96551],
    zoom_start=14,
    tiles='Cartodb Positron'
)

folium.Marker(
    [40.78322, -73.96551],
    icon=ArrowIcon(100, 0)
).add_to(m)

folium.Marker(
    [40.78322, -73.96551],
    icon=ArrowIcon(100, math.pi / 2, color="red")
).add_to(m)

m

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By components of latitude and longitude direction#

m = folium.Map(
    location=[40.78322, -73.96551],
    zoom_start=14,
    tiles='Cartodb Positron'
)

folium.Marker(
    [40.78322, -73.96551],
    icon=ArrowIcon.from_comp((100, 50))
).add_to(m)

folium.Marker(
    [40.78322, -73.96551],
    icon=ArrowIcon.from_comp((-50, 100), color="red")
).add_to(m)

m

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Variation of anchor#

from folium_arrow_icon import ArrowIconHead, ArrowIconBody

def marker(i: int, anchor: str, delta: float) -> folium.Marker:
    lat, lng = 40.78322, -73.96551
    return folium.Marker(
        # shif by (0.001 * i, delta) from (40.78322, -73.96551)
        [lat + 0.001 * i, lng + delta],
        icon=ArrowIcon(
            # wavy visualization
            150 + 50 * math.sin(i * math.pi / 20),
            math.pi / 2,
            # rainbowing by css property "hsl"
            color=f"hsl({i * 10}deg, 100%, 50%)",
            # show border of vector
            border_color="black",
            border_width=1,
            # big head
            head=ArrowIconHead(
                width=12,
                length=20
            ),
            # thin body relative to head
            body=ArrowIconBody(
                width=3
            ),
            # anchor is variable
            anchor=anchor
        )
    )

m = folium.Map(
    location=[40.78322 + 0.015, -73.96551 + 0.035],
    zoom_start=14,
    tiles='Cartodb Positron'
)

for i in range(36):
    # The left is anchor at 'tail' (default)
    marker(i, anchor="tail", delta=0.0).add_to(m)

    # The left is anchor at 'haed'
    marker(i, anchor="head", delta=0.04).add_to(m)

    # The left is anchor at 'mid'
    marker(i, anchor="mid", delta=0.06).add_to(m)

m

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Simple arrow (vector/quiver) icon for folium

Contents

Simple arrow (vector/quiver) icon for folium#

Module contents#

Sample Code#

By length and angle#

By components of latitude and longitude direction#

Variation of anchor#

Indices and tables#