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Mini Shell
Mini Shell
import argparse
import sys
import os
from osgeo import ogr
from osgeo import osr
import anyjson
import shapely.geometry
import shapely.ops
import codecs
import time
format = '%.8f %.8f'
tolerance = 0.01
infile = '/Users/kirilllebedev/Maps/50m-admin-0-countries/ne_50m_admin_0_countries.shp'
outfile = 'map.shp'
# Open the datasource to operate on.
in_ds = ogr.Open( infile, update = 0 )
in_layer = in_ds.GetLayer( 0 )
in_defn = in_layer.GetLayerDefn()
# Create output file with similar information.
shp_driver = ogr.GetDriverByName( 'ESRI Shapefile' )
if os.path.exists('map.shp'):
shp_driver.DeleteDataSource( outfile )
shp_ds = shp_driver.CreateDataSource( outfile )
shp_layer = shp_ds.CreateLayer( in_defn.GetName(),
geom_type = in_defn.GetGeomType(),
srs = in_layer.GetSpatialRef() )
in_field_count = in_defn.GetFieldCount()
for fld_index in range(in_field_count):
src_fd = in_defn.GetFieldDefn( fld_index )
fd = ogr.FieldDefn( src_fd.GetName(), src_fd.GetType() )
fd.SetWidth( src_fd.GetWidth() )
fd.SetPrecision( src_fd.GetPrecision() )
shp_layer.CreateField( fd )
# Load geometries
geometries = []
for feature in in_layer:
geometry = feature.GetGeometryRef()
geometryType = geometry.GetGeometryType()
if geometryType == ogr.wkbPolygon or geometryType == ogr.wkbMultiPolygon:
shapelyGeometry = shapely.wkb.loads( geometry.ExportToWkb() )
#if not shapelyGeometry.is_valid:
#buffer to fix selfcrosses
#shapelyGeometry = shapelyGeometry.buffer(0)
if shapelyGeometry:
geometries.append(shapelyGeometry)
in_layer.ResetReading()
start = int(round(time.time() * 1000))
# Simplification
points = []
connections = {}
counter = 0
for geom in geometries:
counter += 1
polygons = []
if isinstance(geom, shapely.geometry.Polygon):
polygons.append(geom)
else:
for polygon in geom:
polygons.append(polygon)
for polygon in polygons:
if polygon.area > 0:
lines = []
lines.append(polygon.exterior)
for line in polygon.interiors:
lines.append(line)
for line in lines:
for i in range(len(line.coords)-1):
indexFrom = i
indexTo = i+1
pointFrom = format % line.coords[indexFrom]
pointTo = format % line.coords[indexTo]
if pointFrom == pointTo:
continue
if not (pointFrom in connections):
connections[pointFrom] = {}
connections[pointFrom][pointTo] = 1
if not (pointTo in connections):
connections[pointTo] = {}
connections[pointTo][pointFrom] = 1
print int(round(time.time() * 1000)) - start
simplifiedLines = {}
pivotPoints = {}
def simplifyRing(ring):
coords = list(ring.coords)[0:-1]
simpleCoords = []
isPivot = False
pointIndex = 0
while not isPivot and pointIndex < len(coords):
pointStr = format % coords[pointIndex]
pointIndex += 1
isPivot = ((len(connections[pointStr]) > 2) or (pointStr in pivotPoints))
pointIndex = pointIndex - 1
if not isPivot:
simpleRing = shapely.geometry.LineString(coords).simplify(tolerance)
if len(simpleRing.coords) <= 2:
return None
else:
pivotPoints[format % coords[0]] = True
pivotPoints[format % coords[-1]] = True
simpleLineKey = format % coords[0]+':'+format % coords[1]+':'+format % coords[-1]
simplifiedLines[simpleLineKey] = simpleRing.coords
return simpleRing
else:
points = coords[pointIndex:len(coords)]
points.extend(coords[0:pointIndex+1])
iFrom = 0
for i in range(1, len(points)):
pointStr = format % points[i]
if ((len(connections[pointStr]) > 2) or (pointStr in pivotPoints)):
line = points[iFrom:i+1]
lineKey = format % line[-1]+':'+format % line[-2]+':'+format % line[0]
if lineKey in simplifiedLines:
simpleLine = simplifiedLines[lineKey]
simpleLine = list(reversed(simpleLine))
else:
simpleLine = shapely.geometry.LineString(line).simplify(tolerance).coords
lineKey = format % line[0]+':'+format % line[1]+':'+format % line[-1]
simplifiedLines[lineKey] = simpleLine
simpleCoords.extend( simpleLine[0:-1] )
iFrom = i
if len(simpleCoords) <= 2:
return None
else:
return shapely.geometry.LineString(simpleCoords)
def simplifyPolygon(polygon):
simpleExtRing = simplifyRing(polygon.exterior)
if simpleExtRing is None:
return None
simpleIntRings = []
for ring in polygon.interiors:
simpleIntRing = simplifyRing(ring)
if simpleIntRing is not None:
simpleIntRings.append(simpleIntRing)
return shapely.geometry.Polygon(simpleExtRing, simpleIntRings)
results = []
for geom in geometries:
polygons = []
simplePolygons = []
if isinstance(geom, shapely.geometry.Polygon):
polygons.append(geom)
else:
for polygon in geom:
polygons.append(polygon)
for polygon in polygons:
simplePolygon = simplifyPolygon(polygon)
if not (simplePolygon is None or simplePolygon._geom is None):
simplePolygons.append(simplePolygon)
if len(simplePolygons) > 0:
results.append(shapely.geometry.MultiPolygon(simplePolygons))
else:
results.append(None)
# Process all features in input layer.
in_feat = in_layer.GetNextFeature()
counter = 0
while in_feat is not None:
if results[counter] is not None:
out_feat = ogr.Feature( feature_def = shp_layer.GetLayerDefn() )
out_feat.SetFrom( in_feat )
out_feat.SetGeometryDirectly(
ogr.CreateGeometryFromWkb(
shapely.wkb.dumps(
results[counter]
)
)
)
shp_layer.CreateFeature( out_feat )
out_feat.Destroy()
else:
print 'geometry is too small: '+in_feat.GetField(16)
in_feat.Destroy()
in_feat = in_layer.GetNextFeature()
counter += 1
# Cleanup
shp_ds.Destroy()
in_ds.Destroy()
print int(round(time.time() * 1000)) - start
Zerion Mini Shell 1.0