Draw circles and circle markers in python folium

Skill - Draw circles and circle markers in python folium

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Skills Required

• Setup python development environment
• Basic Printing in Python
• Commenting in Python
• Managing Variables in python
• Introduction to Folium for interactive maps in python

Please make sure to have all the skills mentioned above to understand and execute the code mentioned below. Go through the above skills if necessary for reference or revision

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In this post we will learn how to draw circles in folium maps. See this post to learn about folium libary basics

Draw a simple circle with location and radius

• location - latitude, longitude location of the center of the circle
• radius - radius of the circle in meters

import folium

mapObj = folium.Map(location=[23.294059708387206, 78.26660156250001], zoom_start=6)

folium.Circle(location=[23.294059708387206, 78.26660156250001],
              radius=50000
              ).add_to(mapObj)

mapObj.save('output.html')

Circle stroke and fill options

• all the styling options can be found at https://leafletjs.com/reference-1.6.0.html#path . Use snake_case instead of camelCase for specifying options in python
• Some of the important styling options are
  • stroke - set to True to enable line stroke, default is True
  • weight - line stroke width in pixels, default is 5
  • color - line stroke color
  • opacity - line stroke opacity
  • fill - set to True to enable filling with color, default is False
  • fill_color - fill Color
  • fill_opacity - ranges between 0 to 1. 0 means transparent, 1 means opaque

import folium

mapObj = folium.Map(location=[23.294059708387206, 78.26660156250001], zoom_start=6)

folium.Circle(location=[23.294059708387206, 78.26660156250001],
              radius=50000,
              color='green',
              weight=6,
              fill_color='red',
              fill_opacity = 0.5
              ).add_to(mapObj)

mapObj.save('output.html')

Difference between Circle and CircleMarker

The radius in Circle is defined in meters, where as the radius in CircleMarker is defined in pixels

import folium

mapObj = folium.Map(location=[23.294059708387206, 78.26660156250001], zoom_start=6)

folium.CircleMarker(location=[23.294059708387206, 78.26660156250001],
              radius=50
              ).add_to(mapObj)

mapObj.save('output.html')

Circle with tooltip and popup

import folium

mapObj = folium.Map(location=[23.294059708387206, 78.26660156250001], zoom_start=6)

folium.Circle(location=[23.294059708387206, 78.26660156250001],
              radius=50000,
              fill=True,
              tooltip="This is a tooltip text",
              popup=folium.Popup("""<h2>This is a popup</h2><br/>
              This is a <b>new line</b><br/>
              <img src="https://www.w3schools.com/html/pic_trulli.jpg" alt="Trulli" style="max-width:100%;max-height:100%">""", max_width=500)
              ).add_to(mapObj)

mapObj.save('output.html')

Keep shapes in different layer

from os import name
import folium

mapObj = folium.Map(location=[23.294059708387206, 78.26660156250001], zoom_start=6)

# create a layer on the map object
shapesLayer = folium.FeatureGroup(name="circles").add_to(mapObj)

folium.Circle(location=[23.294059708387206, 78.26660156250001],
              radius=50000,
              fill=True
              ).add_to(shapesLayer)

folium.LayerControl().add_to(mapObj)

mapObj.save('output.html')

Complete example

import folium

mapObj = folium.Map(location=[23.294059708387206, 78.26660156250001],
                    zoom_start=6)

shapesLayer = folium.FeatureGroup(name="circles").add_to(mapObj)

circlesData = [
    [25, 74, 80000],
    [22, 79, 60000],
    [26, 82, 90000]
]

for cData in circlesData:
    folium.Circle(location=[cData[0], cData[1]],
                  radius=cData[2],
                  weight=5,
                  color='green',
                  fill_color='red',
                  tooltip="Tooltip text",
                  popup=folium.Popup("""<h2>This is a popup</h2><br/>
                    This is a <b>new line</b><br/>
                    <img src="https://www.w3schools.com/html/pic_trulli.jpg" alt="Trulli" style="max-width:100%;max-height:100%">""", max_width=500)
                  ).add_to(shapesLayer)

folium.LayerControl().add_to(mapObj)

mapObj.save('output.html')

Video

The video for this post can be seen here

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References

• circle styling options - https://leafletjs.com/reference-1.7.1.html#path
• circle docs - https://python-visualization.github.io/folium/modules.html#folium.vector_layers.Circle
• circle marker docs - https://python-visualization.github.io/folium/modules.html#folium.vector_layers.CircleMarker

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