Bokeh is a Python interactive data visualization. It renders its plots using HTML and JavaScript. It targets modern web browsers for presentation providing elegant, concise construction of novel graphics with high-performance interactivity.
Bokeh can be used to plot glyphs over a Google map. A glyph is a hieroglyphic character or a symbol. To use Google maps in Bokeh, we will use the gmap() function of the plotting class.
gmap()
Syntax : gmap(parameters)
Parameters :
- google_api_key : key of the Google API
- map_options : GMapOptions i.e. the configuration specific to the Google map
- active_drag : drag tool that is to be initially active
- active_inspect : inspect tool that is to be initially active
- active_scroll : scroll tool that is to be initially active
- active_tap : tap tool that is to be initially active
- title : title of the Google map
- tools : tools the plot should start with
- x_axis_label : label for the x-axis
- x_axis_location : location of the x-axis
- x_minor_ticks : number of minor ticks between adjacent x-axis major ticks
- y_axis_label : label for the y-axis
- y_axis_location : location of the y-axis
- y_minor_ticks : number of minor ticks between adjacent y-axis major ticks
Returns : an object of the class GMap
Now let us see how to configure the Google map using the GMapOptions() function :
GMapOptions()
Syntax : GMapOptions(parameters)
Parameters :
- lat : latitude where the Google map is to be centered
- lng : longitude where the Google map is to be centered
- map_type : type of map to be used for the plot, here are the map types available :
- hybrid
- roadmap
- satellite
- terrain
- name : name for the Google map
- scale_control : whether the Google map should display its distance scale control
- styles : style of map to be used for the plot
- subscribed_events : list of events that are subscribed to by Python callbacks
- tags : tags associated with the Google map model
- tilt : tilting the angle of the map
- zoom : initial zoom level of the Google map
- apply_theme : theme of the model
Returns : an object of the class GMapOptions
Let us see how to plot glyphs over a Google Map :
- Import the required libraries and modules :
- gmap from bokeh.plotting
- ColumnDataSource and GMapOptions from bokeh.models
- output_file and show from bokeh.io
- Create a file to store our model using
output_file(). - Configure the Google map using
GMapOptions(). - Generate a GoogleMap object using
gmap(). - Determine the coordinates of the glyphs using
ColumnDataSource(). - Generate the glyphs on the created Google map object.
- Display the Google map using
show().
# importing the required modules from bokeh.plotting import gmap from bokeh.models import ColumnDataSource, GMapOptions from bokeh.io import output_file, show # file to save the model output_file("gfg.html") # configuring the Google map lat = 28.7041lng = 77.1025map_type = "hybrid"zoom = 11google_map_options = GMapOptions(lat = lat, lng = lng, map_type = map_type, zoom = zoom) # generating the Google map google_api_key = "" title = "Delhi"google_map = gmap(google_api_key, google_map_options, title = title) # the coordinates of the glyphs source = ColumnDataSource( data = dict(lat = [28.6, 28.65, 28.7, 28.75, 28.8, 28.85], lon = [76.95, 77, 77.05, 77.1, 77.15, 77.25])) # generating the glyphs on the Google map x = "lon"y = "lat"size = 20fill_color = "red"fill_alpha = 1google_map.square(x = x, y = y, size = size, fill_color = fill_color, fill_alpha = fill_alpha, source = source) # displaying the model show(google_map) |
Output :
