Pan/zoom shape file with Python

plot_shapefile_with_zoom.py

#You can download shape files (.sh and .shx) from https://www.naturalearthdata.com/downloads/
#Put .shx files into the same folder as .sh file
#Şamil Korkmaz, December 9th 2023

import geopandas as gpd
import matplotlib.pyplot as plt

def plot_shapefile(shapefile_path1, shapefile_path2, shapefile_path3):
    # Load shape files
    gdf1 = gpd.read_file(shapefile_path1)
    gdf2 = gpd.read_file(shapefile_path2)
    gdf3 = gpd.read_file(shapefile_path3)

    # Create a plot
    fig, ax = plt.subplots()
    ax.set_facecolor('#000080')  # Set the background color to blue
    gdf1.plot(ax=ax, alpha=1, color='#D2B48C')  # Adjust alpha for transparency if needed
    gdf2.plot(ax=ax, alpha=1)
    gdf3.plot(ax=ax, alpha=0.05, edgecolor='k')  # Change edgecolor as needed

    ax.set_xlim([20, 50])
    ax.set_ylim([30, 50])
     # Add a red dot at the specified coordinates
    ax.plot(33, 39, marker='o', color='red', markersize=5)
    
    # State for the pan functionality
    state = {'press': None, 'x0': None, 'y0': None}

    # Function to handle mouse wheel zoom
    def zoom(event):
        if event.button == 'up':
            scale_factor = 1/1.5
        elif event.button == 'down':
            scale_factor = 1.5
        else:
            return

        xlim = ax.get_xlim()
        ylim = ax.get_ylim()

        xdata = event.xdata
        ydata = event.ydata

        if xdata is None or ydata is None:  # Event out of plot area
            return

        ax.set_xlim([xdata - (xdata-xlim[0]) * scale_factor, xdata + (xlim[1]-xdata) * scale_factor])
        ax.set_ylim([ydata - (ydata-ylim[0]) * scale_factor, ydata + (ylim[1]-ydata) * scale_factor])
        
        ax.figure.canvas.draw_idle()

    # Mouse press event handler
    def on_press(event):
        if event.button == 3:  # Right mouse button
            state['press'] = True
            state['x0'], state['y0'] = event.xdata, event.ydata

    # Mouse release event handler
    def on_release(event):
        state['press'] = None
        state['x0'] = None
        state['y0'] = None

    # Mouse motion event handler
    def on_motion(event):
        if state['press'] is None or event.xdata is None or event.ydata is None:
            return
        dx = event.xdata - state['x0']
        dy = event.ydata - state['y0']
        xlim, ylim = ax.get_xlim(), ax.get_ylim()
        ax.set_xlim(xlim[0] - dx, xlim[1] - dx)
        ax.set_ylim(ylim[0] - dy, ylim[1] - dy)
        fig.canvas.draw_idle()

    # Connect the event handlers
    fig.canvas.mpl_connect('scroll_event', zoom)
    fig.canvas.mpl_connect('button_press_event', on_press)
    fig.canvas.mpl_connect('button_release_event', on_release)
    fig.canvas.mpl_connect('motion_notify_event', on_motion)

    # Show the plot
    plt.show()

plot_shapefile('ne_10m_admin_0_countries.shp', 'ne_10m_lakes.shp', 'ne_10m_graticules_5.shp')