split_by_attribute.py

# -*- coding: utf-8 -*-

from osgeo import ogr

roadShpPath = "D:\\DonneesM2\\UMZ_2000_Cut.shp"
fieldToUse = 'Type'

driver = ogr.GetDriverByName("ESRI Shapefile")
datasource = driver.Open(roadShpPath)
layer = datasource.GetLayer()
layerFields = layer.GetLayerDefn()
layerList = []
for i in xrange(layerFields.GetFieldCount()):
    layerList.append(layerFields.GetFieldDefn(i).GetName())
fieldIndex = layerList.index(fieldToUse)

# 1 - On récupere les valeurs de l'attribut
uniqueValuesList = []
# On boucle sur toutes les entités, et on ajoute la valeur si pas déjà dans la liste
feat = layer.GetNextFeature()
while feat is not None:
    featAttributeValue = feat.GetFieldAsString(fieldIndex)
    try:
        uniqueValuesList.index(featAttributeValue)
    except ValueError:
        uniqueValuesList.append(featAttributeValue)
    feat.Destroy()
    feat = layer.GetNextFeature()
# 2 - On lance une boucle
# Première boucle sur les attributs
for i in uniqueValuesList:
    # On crée le shp qui accueillera nos valeurs
    # Il sera nommé comme le shape original, auquel on ajoute _value
    newShapePath = roadShpPath.rstrip('.shp') + '_' + str(i) + '.shp'
    newDriver = ogr.GetDriverByName('ESRI Shapefile')
    newDS = newDriver.CreateDataSource(newShapePath)
    newDS.CopyLayer(layer, str(i))
    newLayer = newDS.GetLayer()
    sqlQuery = fieldToUse + " <> '" + str(i) + "'"
    newLayer.SetAttributeFilter(sqlQuery)
    newFeat = newLayer.GetNextFeature()
    featToDeleteList = []
    while newFeat is not None:
        featToDeleteList.append(newFeat.GetFID())
        newFeat.Destroy()
        newFeat = newLayer.GetNextFeature()
    featToDeleteList.sort()
    featToDeleteList.reverse()
    for featFID in featToDeleteList:
        newLayer.DeleteFeature(featFID)
    newDS.Destroy()
datasource.Destroy()