"""
Térinformatikai algoritmusok
Shapefile-ok kezelése Pythonban
Máté Cserép <mcserep@inf.elte.hu>
"""

import shapefile                # pip3 install pyshp
import matplotlib.pyplot as plt	# pip3 install matplotlib

# Open a shapefile (.shp)
# dBase file of attributes (.dbf) is automatically detected by name convention
# Source: http://gis.inf.elte.hu/files/public/elte-megye
sf = shapefile.Reader('megye_region.shp')
# Check whether files contains polygons
if sf.shapeType == shapefile.POLYGON:
	print("This file contains polygons")

# Print the number of shapes (geometries) in the file
print("Number of counties: {0}".format(len(sf.shapes())))

print("------------------")

# Start new plot figure
plt.figure()
# Iterate through all the shapes
for shape in sf.shapes():
	# Only consider the first polygon if multiple parts are defined
	end = len(shape.points) if len(shape.parts) == 1 else shape.parts[1] - 1
	
	# Get the X an Y positions into separate lists
	xs = [coord[0] for coord in shape.points[:end]]
	ys = [coord[1] for coord in shape.points[:end]]
	
	# Add polygon to plot
	plt.plot(xs, ys)
	
# Display plot ...
plt.show() 
# ... or save plot
#plt.savefig('map.png')