Add_trace for multiple px.line_mapbox figures with geographic lines

📊 Plotly Python
1

I am trying to highlight particular lines in a px.line_mapbox, I tried using color discrete but couldn’t figure that out using a geodataframe. So I thought to merge two line graphs into one of different colors, but this doesn’t seem to work either. What is the best way to color a few lines in a px.line_mapbox based on a particular attribute from a callback?

def getLines(gdf):
    lats = []
    lons = []
    names = []

    for feature, name in zip(gdf.geometry, gdf.Name):
        if isinstance(feature, shapely.geometry.linestring.LineString):
            linestrings = [feature]
        elif isinstance(feature, shapely.geometry.multilinestring.MultiLineString):
            linestrings = feature.geoms
        else:
            continue
        for linestring in linestrings:
            x, y = linestring.xy
            lats = np.append(lats, y)
            lons = np.append(lons, x)
            names = np.append(names, [name]*len(y))
            lats = np.append(lats, None)
            lons = np.append(lons, None)
            names = np.append(names, None)
    return lats, lons, names


gdf = src_gdf.query('names != "Line 1"')

lats, lons, names = getLines(gdf)


boxfig = px.line_mapbox(lat=lats, lon=lons, hover_name=names, 
                        mapbox_style="stamen-terrain", zoom=5)
boxfig.update_traces(line_color='#0000ff', line_width=2)


getdf = geo_df2.query('names == "Line 1"')
lat, lon, _ = getLines(getdf)
boxfig2 = px.line_mapbox(lat=lat, lon=lon,)
boxfig2.update_traces(line_color='#FF5733', line_width=2)
boxfig.add_trace(boxfig2)

What i am trying to do is load the start and end points for geographic locations, then highlight certain routes based on my callbacks.

Would anyone know the best way to do this?

2

Hello @wongkong ,

I am not entirely sure if I understood you correctly. But based on this

I understand that you would like to define the color of a specific trace (line) in your plot. With the selector parameter you can do so.

import plotly.express as px
import pandas as pd

# data source
us_cities = pd.read_csv("https://raw.githubusercontent.com/plotly/datasets/master/us-cities-top-1k.csv")

# two states for different traces
ny = us_cities.query("State in ['New York']")
oh = us_cities.query("State in ['Ohio']")


# create figure
fig = px.line_mapbox(ny, lat="lat", lon="lon", zoom=3, height=300)

# add trace
fig.add_trace(px.line_mapbox(oh,lat='lat', lon='lon').data[0])

# define color of each trace
fig.update_traces(line=dict(color='purple'), selector=0)
fig.update_traces(line=dict(color='red'), selector=1)

# update general layout
fig.update_layout(
    mapbox_style="stamen-terrain", 
    mapbox_zoom=4, 
    mapbox_center_lat = 41,
    margin={"r":0,"t":0,"l":0,"b":0}
)

fig.show()

Which creates

newplot(10)
newplot(10)1471×360 303 KB

4

Yeah, it was user error