script to generate random vectors which may be used for benchmarks

scripts/random_vector.py

@@ -0,0 +1,111 @@
+#!/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" )
+