Mask mismatch at poles

[WasabiThumb]

Wikimedia "Mercator Projection" vs Global Land Mask (green & red). Green means an antipode with land on both sides. I believe my x,y to lat, long coordinate conversion is accurate +/- <1 degree, feel free to check it out yourself:

import numpy as np;
import math;
def XYToLatLong(x,y):
    longitude = (x/(mapWidth/360))-180;
    mercN = ((-y + (mapHeight/2))*(2*math.pi))/mapWidth;
    latRad = 2*(np.arctan(np.exp(mercN))-(math.pi/4));
    latitude = latRad/(math.pi/180);

    return latitude,longitude

[toddkarin]

Hmm, I'm not sure why this is, please try this code to see if you get the right map:

"""
Example make map of world
"""

from global_land_mask import globe
from mpl_toolkits.basemap import Basemap
import numpy as np
import matplotlib
matplotlib.use('TkAgg')
import matplotlib.pyplot as plt


# Lat/lon points to get
lat = np.linspace(-90,90,1000)
lon = np.linspace(-180,180,1002)

# Make a grid
lon_grid, lat_grid = np.meshgrid(lon,lat)

# Get whether the points are on land.
z = globe.is_land(lat_grid, lon_grid)

# Set up map
fig = plt.figure(0, figsize=(5.5, 4.5))
plt.clf()
ax = fig.add_axes([0.1, 0.1, 0.8, 0.8])

m = Basemap(projection='cyl', resolution=None,
            llcrnrlat=-90, urcrnrlat=90,
            llcrnrlon=-180, urcrnrlon=180)

cs = m.contourf(lon_grid, lat_grid, z,
                levels=[-0.5, 0.5,1.5],
                cmap="jet",
                latlon=True)
plt.show()

plt.savefig('example_plot_globe_map_globe.png',
            bbox_inches='tight',
            dpi=400)