geospatialpython/shp2img.py at master · GeospatialPython/geospatialpython · GitHub

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"""

shp2img.py - creates a png image and world file (.pgw) from a shapefile

containing a single polygon.

author: jlawhead@geospatialpyton.com

date: 20101204

This script requires the Python Imaging Library.

The sample shapefile used is available at:

http://geospatialpython.googlecode.com/files/Mississippi.zip

"""

import shapefile

import Image, ImageDraw

# Read in a shapefile

r = shapefile.Reader("mississippi")

xdist = r.bbox[2] - r.bbox[0]

ydist = r.bbox[3] - r.bbox[1]

iwidth = 400

iheight = 600

xratio = iwidth/xdist

yratio = iheight/ydist

pixels = []

for x,y in r.shapes()[0].points:

px = int(iwidth - ((r.bbox[2] - x) * xratio))

py = int((r.bbox[3] - y) * yratio)

pixels.append((px,py))

img = Image.new("RGB", (iwidth, iheight), "white")

draw = ImageDraw.Draw(img)

draw.polygon(pixels, outline="rgb(203, 196, 190)", fill="rgb(198, 204, 189)")

img.save("mississippi.png")

# Create a world file

wld = file("mississippi.pgw", "w")

wld.write("%s\n" % (xdist/iwidth))

wld.write("0.0\n")

wld.write("-%s\n" % (ydist/iheight))

wld.write("%s\n" % r.bbox[0])

wld.write("%s\n" % r.bbox[3])

wld.close

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