Plotly Mapbox 标记不渲染（圆圈除外）

Question

如果我修改其中一个 Plotly 示例 ("Lines on Mapbox maps using Scattermapbox traces") 以使用不同的标记，这些标记将不再出现在地图上。

如何让other kinds of supported markers 显示？

import plotly.graph_objects as go

# Circles appear
fig = go.Figure(go.Scattermapbox(
    mode = "markers+lines",
    lon = [10, 20, 30],
    lat = [10, 20,30],
    marker = {'size': 10, 'symbol':'circle'}))


# Markers do not
fig.add_trace(go.Scattermapbox(
    mode = "markers+lines",
    lon = [-50, -60,40],
    lat = [30, 10, -20],
    marker = {'size': 10, 'symbol':'marker'}))

fig.update_layout(
    margin ={'l':0,'t':0,'b':0,'r':0},
    mapbox = {
        'center': {'lon': 10, 'lat': 10},
        'style': "stamen-terrain",
        'center': {'lon': -20, 'lat': -20},
        'zoom': 1})

fig.show()

empet in this forum 发布的示例代码根本不为我呈现（除了标题）

Answer 1

• plotly / ma​​pbox 中出现多个符号不起作用的问题。像你一样，我发现使用自定义 mapbox 地图的工作不起作用
• 已采取下载 Maki 图标并将其转换为 shapely / geopandas 的方法，以便我可以构建 geojson 层
• SVG转换过程真的来自这个答案https://gis.stackexchange.com/questions/301605/how-to-create-shape-in-shapely-from-an-svg-path-element
• 这种方法的主要问题是它依赖于许多额外的库
• 使用它 使用起来很简单，主要缺点是图标不随缩放而调整大小。这可以在一定程度上解决（见另一个答案Plotly - Adding Scatter Geo points and traces on top of Density Mapbox）

import requests
import svgpath2mpl, shapely.geometry, shapely.affinity
from pathlib import Path
from zipfile import ZipFile
import pandas as pd
import geopandas as gpd
import json
import numpy as np


# download maki icons
# https://github.com/mapbox/maki/tree/main/icons
f = Path.cwd().joinpath("maki")
if not f.is_dir():
    f.mkdir()
f = f.joinpath("maki.zip")
if not f.exists():
    r = requests.get("https://github.com/mapbox/maki/zipball/main")
    with open(f, "wb") as f:
        for chunk in r.iter_content(chunk_size=128):
            f.write(chunk)

fz = ZipFile(f)
fz.extractall(f.parent)

def to_shapely(mpl, simplify=0):
    p = shapely.geometry.MultiPolygon([shapely.geometry.Polygon(a).simplify(simplify) for a in mpl])
    p = shapely.affinity.affine_transform(p,[1, 0, 0, -1, 0, 0],)
    p = shapely.affinity.affine_transform(p,[1, 0, 0, 1, -p.centroid.x, -p.centroid.y],)
    return p

# convert SVG icons to matplolib geometries and then into shapely geometries
# keep icons in dataframe for further access...
SIMPLIFY=.1
dfi = pd.concat(
    [
        pd.read_xml(sf).assign(
            name=sf.stem,
            mpl=lambda d: d["d"].apply(
                lambda p: svgpath2mpl.parse_path(p).to_polygons()
            ),
            shapely=lambda d: d["mpl"].apply(lambda p: to_shapely(p, simplify=SIMPLIFY)),
        )
        for sf in f.parent.glob("**/*.svg")
    ]
).set_index("name")

# build a geojson layer that can be used in plotly mapbox figure layout
def marker(df, marker="marker", size=1, color="green", lat=51.379997, lon=-0.406042):
    m = df.loc[marker, "shapely"]
    if isinstance(lat, float):
        gs = gpd.GeoSeries(
            [shapely.affinity.affine_transform(m, [size, 0, 0, size, lon, lat])]
        )
    elif isinstance(lat, (list, pd.Series, np.ndarray)):
        gs = gpd.GeoSeries(
            [
                shapely.affinity.affine_transform(m, [size, 0, 0, size, lonm, latm])
                for latm, lonm in zip(lat, lon)
            ]
        )
    return {"source":json.loads(gs.to_json()), "type":"fill", "color":color}

# display all icons to make sure they look ok...
gpd.GeoSeries(
    [
        shapely.affinity.affine_transform(
            s, [1, 0, 0, 1, (i % 20) * 20, (i // 20) * 20]
        )
        for i, s in enumerate(dfi["shapely"])
    ]
).plot()

dfi.loc["karaoke", "shapely"]

使用它

import plotly.graph_objects as go

# Circles appear
fig = go.Figure(
    go.Scattermapbox(
        mode="markers+lines",
        lon=[10, 20, 30],
        lat=[10, 20, 30],
        marker={"size": 10, "symbol": "circle"},
    )
)


# Markers do not
fig.add_trace(
    go.Scattermapbox(
        mode="markers+lines",
        lon=[-50, -60, 40],
        lat=[30, 10, -20],
        marker={"size": 10, "symbol": "circle"},
    )
)

fig.update_layout(
    margin={"l": 0, "t": 0, "b": 0, "r": 0},
    mapbox={
        "center": {"lon": 10, "lat": 10},
        "style": "stamen-terrain",
        "center": {"lon": -20, "lat": -20},
        "zoom": 1,
    },
)

fig.update_layout(
    mapbox={
        "layers": [
            marker(
                dfi, "soccer", size=.5, color="blue", lon=[10, 20, 30], lat=[10, 20, 30]
            ),
            marker(
                dfi, "star", size=.5, color="red", lon=[-50, -60, 40], lat=[30, 10, -20]
            ),

            
        ]
    }
)

输出