Welcome to Gplot’s documentation!

Introduction

Gplot is a (thin) wrapper around matplotlib, basemap and cartopy for quick and easy creations of geographical plots. It is designed to create publish-ready figures with as few lines as possible, while preserving the possibility to fine-tune various aspects of the plots.

Installation

Install from conda

gplot can be installed in an existing conda environment using:

conda install -c guangzhi gplot

This will install gplot and its dependencies for Python 3.

Dependencies

• Mandatory:

  • OS: Linux or MacOS. Windows is not tested.

  • Python: >= 3.

  • numpy

  • matplotlib: developed in 3.2.2. NOTE that versions later than 3.2.2 are incompatible with basemap.

• Optional:

  • scipy: optional, developed in 1.2.1. For 2D interpolation in quiver plots only.

  • For plotting the geography: basemap or Cartopy.

    • basemap: developed in 1.2.0.

    • Cartopy: developed in 0.16.0, not fully supported yet.

  • For netCDF file reading: netCDF4 or CDAT or xarray or iris.

    • netCDF4: developed in 1.5.5.1.

    • the cdms module of CDAT: developed in 3.1.5.

    • xarray: not supported yet.

    • iris: not supported yet.

Quick start

After installation of gplot and basemap, create an isofill/contourf plot of the global sea level pressure field (sample data included in the installation) using the following snippet:

import matplotlib.pyplot as plt
import gplot
from gplot.lib import netcdf4_utils

var = netcdf4_utils.readData('msl')
lats = netcdf4_utils.readData('latitude')
lons = netcdf4_utils.readData('longitude')

figure = plt.figure(figsize=(12, 10), dpi=100)
ax = figure.add_subplot(111)
iso = gplot.Isofill(var)
gplot.plot2(var, iso, ax, xarray=lons, yarray=lats,
            title='Default basemap', projection='cyl',
            nc_interface='netcdf4')
figure.show()

The output is given below:

Fig. 1 Default contourf plot of global surface pressure field (in Pa), from ERA-I.

Documentation

• Basic workflow
  • Overall design of gplot
  • Basic plotting syntax
• Isofill/Contourf plots
  • The Isofill class
  • Define the contour levels
  • Choose the colormap
  • Split the colormap colors
  • Overlay with stroke
  • The mappable object
• Isoline/Contour plots
  • The Isoline class
  • Line width and color controls
  • Use dashed line for negatives
  • Label the contour lines
  • The mappable object
• Boxfill/imshow plots
  • The Boxfill and Pcolor classes
  • Basic plot example
  • The mappable object
• Colorbar
  • Positioning of the colorbar
  • Overflows on a colorbar
  • Alternating top and bottom ticks of a horizontal colorbar
• Quiver plots
  • The Quiver class
  • Control the quiver density
  • Control the quiver lengths
  • Quiver overlay
  • Curved quiver plots
  • The mappable object
• Subplot layouts
  • Recommended way of creating subplots
  • Automatically label the subplots with alphabetic indices
• Others
  • netCDF interfaces
  • Axes ticks and ticklabels
  • Color for missing values
  • Font size
  • Default parameters

gplot module contents

• base_utils.py
• basemap_utils.py
• cdat_utils.py
• netcdf4_utils.py
• cartopy_utils.py

Github and Contact

The code of this package is hosted at https://github.com/Xunius/gplot.

For any queries, please contact xugzhi1987@gmail.com.

Contributing and getting help

We welcome contributions from the community. Please create a fork of the project on GitHub and use a pull request to propose your changes. We strongly encourage creating an issue before starting to work on major changes, to discuss these changes first.

For help using the package, please post issues on the project GitHub page.

License

LICENSE

Indices and tables

• Index

• Module Index

• Search Page