In [1]:
%matplotlib inline
import matplotlib.pyplot as plt
In [2]:
# Import, and set to log to the console. (See the console which is running
# Jupyter notebook for logging about HTTP requests.)
import tilemapbase
tilemapbase.start_logging()
In [3]:
# Don't need if you have run before; DB file will already exist.
tilemapbase.init(create=True)
In [4]:
# Use open street map
t = tilemapbase.tiles.build_OSM()
In [5]:
# My current office at the University of Leeds
my_office = (-1.554934, 53.804198)
degree_range = 0.003
extent = tilemapbase.Extent.from_lonlat(my_office[0] - degree_range, my_office[0] + degree_range,
my_office[1] - degree_range, my_office[1] + degree_range)
extent = extent.to_aspect(1.0)
extent
Out[5]:
In [6]:
# On my desktop, DPI gets scaled by 0.75
fig, ax = plt.subplots(figsize=(8, 8), dpi=100)
ax.xaxis.set_visible(False)
ax.yaxis.set_visible(False)
plotter = tilemapbase.Plotter(extent, t, width=600)
plotter.plot(ax, t)
x, y = tilemapbase.project(*my_office)
ax.scatter(x,y, marker=".", color="black", linewidth=20)
None
This plotting method uses PIL to assemble each tile into one big image, and then displays this using matplotlib.
If instead we place each tile in the plot using imshow, then we get distortion. If you look closely at e.g. the "Maths / Earth & Environment" text, you'll this.
In [7]:
fig, ax = plt.subplots(figsize=(8, 8), dpi=100)
ax.xaxis.set_visible(False)
ax.yaxis.set_visible(False)
plotter.plotlq(ax, t)
x, y = tilemapbase.project(*my_office)
ax.scatter(x,y, marker=".", color="black", linewidth=20)
None
When producing figures for printing, a higher resolutions might be appropriate. This can be achieved by increasing the zoom level. The figure could be saved as:
fig.savefig("test.pdf", dpi=200)
This will transparently create a high-DPI PDF file. (It is worth also saving a copy without the dpi=200 and comparing the outputs.)
In [8]:
plotter1 = tilemapbase.Plotter(plotter.extent, t, zoom = plotter.zoom + 1)
fig, ax = plt.subplots(figsize=(8, 8), dpi=100)
ax.xaxis.set_visible(False)
ax.yaxis.set_visible(False)
plotter1.plot(ax, t)
x, y = tilemapbase.project(*my_office)
ax.scatter(x,y, marker=".", color="black", linewidth=20)
None
We can translate a given extent object.
In [9]:
extent1 = extent.with_centre_lonlat(-1.558, 53.804198)
plotter2 = tilemapbase.Plotter(extent1, t, width=600)
fig, ax = plt.subplots(figsize=(8, 8), dpi=100)
plotter2.plot(ax)
It can be convenient to use EPSG:3857 as other GIS systems will support this (e.g. GeoPandas), while "web mercator" is not a recognised standard.
In [10]:
extent2 = extent1.to_project_3857()
plotter3 = tilemapbase.Plotter(extent2, t, width=600)
fig, ax = plt.subplots(figsize=(8, 8), dpi=100)
plotter3.plot(ax)
In [ ]: