# 참고. Folium의 메소드들에 대해서

docstring

Jupyter Notebook에서 함수나 클래스의 기능들, 독스트링(doc string)을 확인하기 위해서는 함수나 클래스 뒤에 ()를 빼고 ?를 넣는다. 예를 들어, Folium의 Map기능의 경우 다음과 같은 내용이 표시된다.

Init signature:
folium.Map(
    location: Union[Sequence[float], NoneType] = None,
    width: Union[str, float] = '100%',
    height: Union[str, float] = '100%',
    left: Union[str, float] = '0%',
    top: Union[str, float] = '0%',
    position: str = 'relative',
    tiles: Union[str, folium.raster_layers.TileLayer, NoneType] = 'OpenStreetMap',
    attr: Union[str, NoneType] = None,
    min_zoom: int = 0,
    max_zoom: int = 18,
    zoom_start: int = 10,
    min_lat: int = -90,
    max_lat: int = 90,
    min_lon: int = -180,
    max_lon: int = 180,
    max_bounds: bool = False,
    crs: str = 'EPSG3857',
    control_scale: bool = False,
    prefer_canvas: bool = False,
    no_touch: bool = False,
    disable_3d: bool = False,
    png_enabled: bool = False,
    zoom_control: bool = True,
    font_size: str = '1rem',
    **kwargs: Union[str, float, bool, Sequence, dict, NoneType],
)
Docstring:     
Create a Map with Folium and Leaflet.js

Generate a base map of given width and height with either default
tilesets or a custom tileset URL. Folium has built-in all tilesets
available in the ``xyzservices`` package. For example, you can pass
any of the following to the "tiles" keyword:

    - "OpenStreetMap"
    - "CartoDB Positron"
    - "CartoDB Voyager"
    - "NASAGIBS Blue Marble"

You can pass a custom tileset to Folium by passing a
:class:`xyzservices.TileProvider` or a Leaflet-style
URL to the tiles parameter: ``http://{s}.yourtiles.com/{z}/{x}/{y}.png``.

You can find a list of free tile providers here:
``http://leaflet-extras.github.io/leaflet-providers/preview/``.
Be sure to check their terms and conditions and to provide attribution
with the `attr` keyword.

Parameters
----------
location: tuple or list, default None
    Latitude and Longitude of Map (Northing, Easting).
width: pixel int or percentage string (default: '100%')
    Width of the map.
height: pixel int or percentage string (default: '100%')
    Height of the map.
tiles: str or TileLayer or :class:`xyzservices.TileProvider`, default 'OpenStreetMap'
    Map tileset to use. Can choose from a list of built-in tiles,
    pass a :class:`xyzservices.TileProvider`,
    pass a custom URL, pass a TileLayer object,
    or pass `None` to create a map without tiles.
    For more advanced tile layer options, use the `TileLayer` class.
min_zoom: int, default 0
    Minimum allowed zoom level for the tile layer that is created.
max_zoom: int, default 18
    Maximum allowed zoom level for the tile layer that is created.
zoom_start: int, default 10
    Initial zoom level for the map.
attr: string, default None
    Map tile attribution; only required if passing custom tile URL.
crs : str, default 'EPSG3857'
    Defines coordinate reference systems for projecting geographical points
    into pixel (screen) coordinates and back.
    You can use Leaflet's values :
    * EPSG3857 : The most common CRS for online maps, used by almost all
    free and commercial tile providers. Uses Spherical Mercator projection.
    Set in by default in Map's crs option.
    * EPSG4326 : A common CRS among GIS enthusiasts.
    Uses simple Equirectangular projection.
    * EPSG3395 : Rarely used by some commercial tile providers.
    Uses Elliptical Mercator projection.
    * Simple : A simple CRS that maps longitude and latitude into
    x and y directly. May be used for maps of flat surfaces
    (e.g. game maps). Note that the y axis should still be inverted
    (going from bottom to top).
control_scale : bool, default False
    Whether to add a control scale on the map.
prefer_canvas : bool, default False
    Forces Leaflet to use the Canvas back-end (if available) for
    vector layers instead of SVG. This can increase performance
    considerably in some cases (e.g. many thousands of circle
    markers on the map).
no_touch : bool, default False
    Forces Leaflet to not use touch events even if it detects them.
disable_3d : bool, default False
    Forces Leaflet to not use hardware-accelerated CSS 3D
    transforms for positioning (which may cause glitches in some
    rare environments) even if they're supported.
zoom_control : bool, default True
    Display zoom controls on the map.
font_size : int or float or string (default: '1rem')
    The font size to use for Leaflet, can either be a number or a
    string ending in 'rem', 'em', or 'px'.
**kwargs
    Additional keyword arguments are passed to Leaflets Map class:
    https://leafletjs.com/reference.html#map

Returns
-------
Folium Map Object

Examples
--------
>>> m = folium.Map(location=[45.523, -122.675], width=750, height=500)
>>> m = folium.Map(location=[45.523, -122.675], tiles="cartodb positron")
>>> m = folium.Map(
...     location=[45.523, -122.675],
...     zoom_start=2,
...     tiles="https://api.mapbox.com/v4/mapbox.streets/{z}/{x}/{y}.png?access_token=mytoken",
...     attr="Mapbox attribution",
... )
File:           c:\users\kdh\miniconda3\envs\ds_study\lib\site-packages\folium\folium.py
Type:           type
Subclasses:

어떤 기능이 있는지, 어떤 식으로 작성하면 되는지, 어떤 자료형인지 나와있다. 이러한 정보들을 바탕으로 코드 작성 시에 바로 기능이 생각나지 않을 때, 새로운 라이브러리를 사용할 때 필요한 기능들을 사전처럼 검색해볼 수 있다.

 

.save('path')

path 안에 경로를 입력하면 지도를 html형태로 저장해준다. 

 

tiles option 

folium.Map() 안에 tiles= 'tiles option' 값을 넣어주면 기본적으로 built-in 되어 있는 지도의 경우 한 번에 제공해준다.

folium의 경우 다음과 같은 값을 제공해준다.

    - "OpenStreetMap"
    - "CartoDB Positron"
    - "CartoDB Voyager"
    - "NASAGIBS Blue Marble"

 

.marker()

지도에 마커를 생성해준다. 

folium.Marker(
    location: Union[Sequence[float], NoneType] = None,
    popup: Union[ForwardRef('Popup'), str, NoneType] = None,
    tooltip: Union[ForwardRef('Tooltip'), str, NoneType] = None,
    icon: Union[folium.map.Icon, NoneType] = None,
    draggable: bool = False,
    **kwargs: Union[str, float, bool, Sequence, dict, NoneType],
)

Parameters
----------
location: tuple or list
    Latitude and Longitude of Marker (Northing, Easting)
popup: string or folium.Popup, default None
    Label for the Marker; either an escaped HTML string to initialize
    folium.Popup or a folium.Popup instance.
tooltip: str or folium.Tooltip, default None
    Display a text when hovering over the object.
icon: Icon plugin
    the Icon plugin to use to render the marker.
draggable: bool, default False
    Set to True to be able to drag the marker around the map.

 

folium.Icon()

아이콘을 예쁘게 꾸며 준다.

folium.Icon(
    color: str = 'blue',
    icon_color: str = 'white',
    icon: str = 'info-sign',
    angle: int = 0,
    prefix: str = 'glyphicon',
    **kwargs: Union[str, float, bool, Sequence, dict, NoneType],
)
Docstring:     
Creates an Icon object that will be rendered
using Leaflet.awesome-markers.

Parameters
----------
color : str, default 'blue'
    The color of the marker. You can use:

        ['red', 'blue', 'green', 'purple', 'orange', 'darkred',
         'lightred', 'beige', 'darkblue', 'darkgreen', 'cadetblue',
         'darkpurple', 'white', 'pink', 'lightblue', 'lightgreen',
         'gray', 'black', 'lightgray']

icon_color : str, default 'white'
    The color of the drawing on the marker. You can use colors above,
    or an html color code.
icon : str, default 'info-sign'
    The name of the marker sign.
    See Font-Awesome website to choose yours.
    Warning : depending on the icon you choose you may need to adapt
    the `prefix` as well.
angle : int, default 0
    The icon will be rotated by this amount of degrees.
prefix : str, default 'glyphicon'
    The prefix states the source of the icon. 'fa' for font-awesome or
    'glyphicon' for bootstrap 3.

https://github.com/lvoogdt/Leaflet.awesome-markers

 

folium.ClickForMarker()

지도 위에 마우스로 클릭했을 때 마커를 생성해준다.

만들어진 지도에 .add_child()메서드를 통해 넣을 수 있고, popup()메소드를 받는다.

 

 

folium.LatLngPopup()

지도를 마우스로 클릭했을 때 위도,경도 정보를 반환해준다. ClickForMarker()과 똑같이 .add_child()메소드를 통해 적용하며, 아무 옵션도 없다.

 

folium.Circle(), folium.CircleMarker()

지도에 동그라미를 표시해준다.

 

folium.Choropleth()

지리데이터 정보를 받아 지도를 시각화해주는 메소드이다.

Init signature:
folium.Choropleth(
    geo_data: Any, # 경계선 좌표값이 담긴 데이터
    data: Union[Any, NoneType] = None, # Series or DataFrame
    columns: Union[Sequence[Any], NoneType] = None, # DataFrame Columns
    key_on: Union[str, NoneType] = None,# 위의 두 데이터를 하나의 옵션으로 묶어준다
    
    # 아래부터는 꾸며주는 옵션
    bins: Union[int, Sequence[float]] = 6,
    fill_color: Union[str, NoneType] = None,
    nan_fill_color: str = 'black',
    fill_opacity: float = 0.6,
    nan_fill_opacity: Union[float, NoneType] = None,
    line_color: str = 'black',
    line_weight: float = 1,
    line_opacity: float = 1,
    name: Union[str, NoneType] = None,
    legend_name: str = '',
    overlay: bool = True,
    control: bool = True,
    show: bool = True,
    topojson: Union[str, NoneType] = None,
    smooth_factor: Union[float, NoneType] = None,
    highlight: bool = False,
    use_jenks: bool = False,
    **kwargs,
)

 

 

이외의 기능들은 아래의 링크를 참고하면 된다.

 

https://nbviewer.jupyter.org/github/python-visualization/folium/tree/master/examples