# -*- coding: utf-8 -*-

"""
Cartopy: Customizing map decoration
=============================================

When plotting data on a latitude-longitude grid, showvar
will add some default components to a Cartopy map. These
can be customized in several ways.

.. _projections: https://scitools.org.uk/cartopy/docs/latest/reference/crs.html#list-of-projections
"""

# %%

import pygeode as pyg
import numpy as np, pylab as pyl
from cartopy import crs as ccrs
import cartopy

# Construct latitude and longitude coordinate system
lat = pyg.gausslat(40)
lon = pyg.regularlon(80, origin=-180, repeat_origin=True)

# Generate x and y components of a vector field on this coordinate system
T = pyg.cos(4*np.pi * lon / 180.) * pyg.exp(-(lat - 40)**2 / (4*10**2))
T.plotatts['plotname'] = ''

pyl.ioff()

# Simply calling showvar will produce a plot using the PlateCarree (cylindrical) projection
# Set nozero to true to remove the zero contour
ax = pyg.showvar(T, nozero = True)

pyl.ion()
ax.render(1)

# %%
# To make this plot more interesting, lets use a Robinson projection.
# We create a ''map'' dictionary with the name of the projection and any arguments
# (See the list of projections_ available).
#
# %%

# Turn off interactivity
pyl.ioff()

# Build CartopyAxis for a Lambert Conformal projection
prj = dict(central_longitude=-90.)
map = dict(projection = 'Robinson', prj_args = prj)

ax = pyg.showvar(T, nozero=True, map = map)

pyl.ion()
ax.render(2)
# %%
#
# As of Cartopy v0.18, the default labeling of the latitude longitude gridlines
# is not very legible, so it is turned off for all projections except PlateCarree and Mercator.
#
# We can turn them back on using the ''map_decor'' dictionary. This gives some direct
# control over the gridlines and coastlines. See :meth:`cartopy.mpl.geoaxes.GeoAxes.gridlines()`
# and :meth:`cartopy.mpl.geoaxes.GeoAxes.coastlines` for keyword arguments
#
# %%

# Choose custom grid labeling settings
gl = dict(color = 'C0', linestyle = '-', \
          draw_labels=True, \
          x_inline=False, y_inline=False, \
          top_labels=True, bottom_labels=True, left_labels=True, right_labels=True,
          rotate_labels=False, \
          xlocs = pyl.MultipleLocator(30), \
          ylocs = pyl.MultipleLocator(30))

# Set resolution and line style of coastlines
cl = dict(resolution='110m', color='0.3', linewidth=2)

pyl.ioff()

# Create a new plot.
ax = pyg.showvar(T, nozero=True, map = map, mapdecor = dict(gridlines = gl, coastlines = cl))

# Turn on matplotlib interactivity
pyl.ion()

# Produce plot (and use this one for the gallery thumbnail)
# sphinx_gallery_thumbnail_number = 3
ax.render(3)

# %%
# This gallery shows how to modify the appearance of maps by passing in appropriate
# dictionaries to showvar; another option is to turn off automatic map decorations
# by passing in ''map_decor = False''. See 
# :doc:`Add Cartopy Features <map_gallery>` for an example.
# %%