gmplot

Common errors

• AttributeError: module 'gmplot' has no attribute 'GoogleMapPlotter'

  cause This usually indicates an outdated `gmplot` installation, a local file named `gmplot.py` shadowing the actual library, or an incorrect import where `gmplot` is treated as the class itself.
  fix 1. Ensure you have the latest `gmplot`: `pip install --upgrade gmplot`. 2. Check if there's a file named `gmplot.py` in your working directory and rename it. 3. Correct the import and instantiation to `import gmplot; gmap = gmplot.GoogleMapPlotter(lat, lon, zoom)`.

• TypeError: 'module' object is not callable

  cause Attempting to call the `gmplot` module directly as a constructor, instead of using the `GoogleMapPlotter` class within it.
  fix The correct way to create a map object is `gmap = gmplot.GoogleMapPlotter(latitude, longitude, zoom_level)`.

• Map displays 'For Development Purposes Only' watermark

  cause A Google Maps API key is required for production use and to remove the watermark, but it has not been provided or is invalid.
  fix Obtain a valid Google Maps API key from the Google Cloud Console and pass it as the `apikey` parameter during `GoogleMapPlotter` instantiation: `gmap = gmplot.GoogleMapPlotter(..., apikey='YOUR_API_KEY')`.

• TypeError: argument of type 'float' is not iterable (when using scatter with size/color)

  cause The `size` or `color` parameter in `scatter()` was passed an iterable (e.g., a tuple or list) when the method expected a single float for `size` or a single string for `color` to apply uniformly, or vice-versa.
  fix If you want a uniform style, pass a single value (e.g., `size=40`, `color='red'`). If you want different styles per point, ensure the list of styles has the same length as your latitude/longitude lists and that the type for each element matches the expected parameter type (e.g., `size=[20, 30, 40]`). Alternatively, loop and plot each point individually if complex individual styling is needed.

Warnings

• gotcha Using Google Maps without an API key will result in a 'For Development Purposes Only' watermark on your generated maps.
  Fix: Obtain a Google Maps API key from the Google Cloud Console and pass it to the `GoogleMapPlotter` constructor using the `apikey` parameter (e.g., `gmap = GoogleMapPlotter(..., apikey='YOUR_API_KEY')`).
• gotcha The `GoogleMapPlotter` class must be instantiated as `gmplot.GoogleMapPlotter(...)`. Trying to call `gmplot()` directly will result in a `TypeError: 'module' object is not callable`.
  Fix: Always use `gmap = gmplot.GoogleMapPlotter(latitude, longitude, zoom)` to create a map object after `import gmplot`.
• gotcha When using `scatter()` or other plotting methods, ensure that iterable arguments like `color`, `size`, or `marker` match the length of `latitudes` and `longitudes`, or provide a single value to apply uniformly.
  Fix: If plotting multiple points with different styles, provide lists of equal length for style parameters (e.g., `color=['red', 'blue']` for two points). If a single style is desired for all points, pass a single value (e.g., `color='red'`).
• gotcha The `plot()` method is used for drawing lines or paths, while `polygon()` is used for drawing filled, closed shapes. Misusing them can lead to unexpected visual output.
  Fix: Use `gmap.plot(lats, lons, ...)` for routes or lines. Use `gmap.polygon(lats, lons, ...)` for filled areas.
• deprecated Python 2 support has been dropped. gmplot is primarily designed and tested for Python 3 environments.
  Fix: Ensure your project runs on Python 3.5 or newer. If you encounter issues on older Python 2 versions, upgrade your Python environment.

Install

• pip install gmplot Install with pip

Imports

• GoogleMapPlotter
  wrong:

  import gmplot; gmap = gmplot()

  correct:

  from gmplot import GoogleMapPlotter

  The primary class to interact with is GoogleMapPlotter, not the module itself.
• gmplot
  wrong:

  from gmplot import gmplot

  correct:

  import gmplot

  Importing the top-level module is common, but accessing internal objects like `gmplot.GoogleMapPlotter` is standard.

Quickstart

This quickstart demonstrates how to create a basic Google Map, add a marker, scatter a few points, and save the result as an interactive HTML file. It highlights the use of `GoogleMapPlotter` and the importance of including an API key for full functionality. The generated HTML file can be opened in a web browser to view the map.

import gmplot
import os

# Replace with your actual coordinates and zoom level
latitude, longitude, zoom = 37.4239163, -122.0946215, 16

# Initialize GoogleMapPlotter with center latitude, longitude, and zoom
# Add your Google Maps API key using os.environ.get('GOOGLE_API_KEY', '')
# to avoid the 'For Development Purposes Only' watermark
gmap = gmplot.GoogleMapPlotter(latitude, longitude, zoom, apikey=os.environ.get('GOOGLE_API_KEY', ''))

# Add a marker
gmap.marker(latitude, longitude, 'cornflowerblue', size=40, title="My Location")

# Add a scatter plot (e.g., nearby points)
more_lats = [37.425, 37.420]
more_lngs = [-122.090, -122.100]
gmap.scatter(more_lats, more_lngs, '#FF0000', size=20, marker=False)

# Draw the map to an HTML file
output_html_file = 'mymap.html'
gmap.draw(output_html_file)

print(f"Map saved to {output_html_file}")