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script to generate random vectors which may be used for benchmarks

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blazek committed May 6, 2013
1 parent 9222f15 commit 3875419f93b8108fb8c37d7f70adcbc45ca09804
Showing with 111 additions and 0 deletions.
  1. +111 −0 scripts/random_vector.py
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#!/usr/bin/env python

# Generates random shapefile which may be used for benchmarks

import os, sys, random, string, math
from osgeo import ogr
from optparse import OptionParser

def error ( msg ):
print msg
sys.exit( 1 )

parser = OptionParser("usage: %prog [options] output")
parser.add_option("-t", "--type", dest="type", type="choice", choices=("point", "line", "polygon"), default="point", help="Geometry type")
parser.add_option("-f", "--features", dest="features", type="int", default=1000, help="Number of features")
parser.add_option("-c", "--coordinates", dest="coordinates", type="int", default=10, help="Number of coordinates per feature (lines and polygons)")
parser.add_option("-a", "--attributes", dest="attributes", type="int", default=10, help="Number of attributes")
parser.add_option("-e", "--extent", dest="extent", type="string", default="-180,-90,180,90", help="Extent")

(options, args) = parser.parse_args()
if len(args) != 1:
error( "Output file path missing" )

(minx, miny, maxx, maxy) = map ( float, options.extent.split(",") )

driverName = "ESRI Shapefile"
drv = ogr.GetDriverByName( driverName )
if drv is None:
error ( "%s driver not available.\n" % driverName )

# delete if exists
try:
if os.path.exists( args[0] ):
drv.DeleteDataSource( args[0] )
except:
pass

ds = drv.CreateDataSource( args[0] )
if ds is None:
error( "Creation of output file failed.\n" )

types = { "point": ogr.wkbPoint, "line": ogr.wkbLineString, "polygon": ogr.wkbPolygon }

lyr = ds.CreateLayer( "out", None, types[options.type] )
if lyr is None:
error ( "Layer creation failed.\n" )

attrTypes = ( ogr.OFTString, ogr.OFTInteger, ogr.OFTReal )
stringWidth = 100
for a in range(0,options.attributes):
attrName = "attr%s" % a
field_defn = ogr.FieldDefn( attrName, random.choice( attrTypes ) )
if field_defn.type == ogr.OFTString:
field_defn.SetWidth( stringWidth )

if lyr.CreateField ( field_defn ) != 0:
error ( "Creating Name field failed.\n" )

feat_defn = lyr.GetLayerDefn()
for f in range(options.features):
feat = ogr.Feature( feat_defn )

buffer = (maxx-minx)/100
if options.type == "point":
geo = ogr.Geometry( ogr.wkbPoint )
x = random.uniform( minx, maxx )
y = random.uniform( miny, maxy )
geo.SetPoint_2D(0, x, y)

elif options.type == "line":
geo = ogr.Geometry(ogr.wkbLineString)
xc = random.uniform( minx+buffer, maxx-buffer )
yc = random.uniform( miny+buffer, maxy-buffer )
for c in range(options.coordinates):
a = c * 2 * math.pi / options.coordinates
r = random.uniform( buffer/10, 9*buffer/10 )
x = xc + r * math.sin(a)
y = yc + r * math.cos(a)
geo.SetPoint_2D(c, x, y)

elif options.type == "polygon":
ring = ogr.Geometry(ogr.wkbLinearRing)
xc = random.uniform( minx+buffer, maxx-buffer )
yc = random.uniform( miny+buffer, maxy-buffer )
for c in range(options.coordinates):
a = c * 2 * math.pi / options.coordinates
r = random.uniform( buffer/10, 9*buffer/10 )
x = xc + r * math.sin(a)
y = yc + r * math.cos(a)
ring.SetPoint_2D(c, x, y)
geo = ogr.Geometry(ogr.wkbPolygon)
geo.AddGeometry ( ring )

feat.SetGeometry(geo)

for i in range(feat_defn.GetFieldCount()):
field_defn = feat_defn.GetFieldDefn(i)
val = None
limit = 10000000
if field_defn.GetType() == ogr.OFTString:
nChars = random.randint(0,stringWidth)
val = ''.join(random.choice(string.ascii_letters+ string.digits) for x in range(nChars) )
elif field_defn.GetType() == ogr.OFTInteger:
val = random.randint( -limit, limit )
elif field_defn.GetType() == ogr.OFTReal:
val = random.uniform ( -limit, limit )
feat.SetField( field_defn.name, val )

if lyr.CreateFeature(feat) != 0:
error ( "Failed to create feature in shapefile.\n" )

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