• python 与开源Gis 书本知识点测试


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

    print(u"python与开源QGis课题研究组")
    #print("汉字")

    #+++++++++++++++++
    #创建矢量数据文件
    #+++++++++++++++++

    try:
        from osgeo import ogr
    except:
        import ogr
        
    driver = ogr.GetDriverByName("ESRI Shapefile")

    import os

    '''
    ds = driver.CreateDataSource("xx_tesp.shp")
    layer = ds.CreateLayer('test',geom_type = ogr.wkbPoint)
    fieldDefn = ogr.FieldDefn('id',ogr.OFTString)
    fieldDefn.SetWidth(4)
    layer.CreateField(fieldDefn)
    featureDefn = layer.GetLayerDefn()
    print(featureDefn)
    feature = ogr.Feature(featureDefn)
    #设定几何形状
    point = ogr.Geometry(ogr.wkbPoint)
    point.SetPoint(0,123,123)
    #设定字段数值
    feature.SetField('id',23)
    #将要素写入到图层
    layer.CreateFeature(feature)
    ds.Destroy()


    import os
    out_shp = "xx_tesp.shp"
    dir(out_shp)
    if os.path.exists(out_shp):
        driver.DeleteDataSource(out_shp)
        
    dir(out_shp)


    point = ogr.Geometry(ogr.wkbPoint)
    print(point)
    point.AddPoint(10,20)
    print(point)
    point.AddPoint(30,20)
    print(point)


    line = ogr.Geometry(ogr.wkbLineString)
    print(line)
    line.AddPoint(10,10)
    print(line)
    line.AddPoint(20,20)
    print(line)
    line.SetPoint(2,30,30)
    print(line)
    print(line.GetPointCount())
    print(line.GetX(0))
    print(line.GetX(1))
    print(line.GetX(3))



    ring = ogr.Geometry(ogr.wkbLinearRing)
    ring.AddPoint(0,0)
    ring.AddPoint(100,0)
    ring.AddPoint(100,100)
    ring.AddPoint(0,100)
    ring.CloseRings()
    print(ring)
    print(type(ring))


    outring = ogr.Geometry(ogr.wkbLinearRing)
    outring.AddPoint(0,0)
    outring.AddPoint(100,0)
    outring.AddPoint(100,100)
    outring.AddPoint(0,100)
    outring.AddPoint(0,0)

    inring = ogr.Geometry(ogr.wkbLinearRing)
    inring.AddPoint(25,25)
    inring.AddPoint(75,25)
    inring.AddPoint(75,75)
    inring.AddPoint(25,75)
    inring.CloseRings()

    polygon = ogr.Geometry(ogr.wkbPolygon)
    polygon.AddGeometry(outring)
    polygon.AddGeometry(inring)
    print(polygon.GetGeometryCount())


    #outring2 = polygon.GetGeometryRef(0)
    #inring2 = polygon.GetGeometryRef(1)
    #print(outring2)
    #print(inring2)

    for ringx in range(polygon.GetGeometryCount()):
        print(polygon.GetGeometryRef(ringx))


    multipoint = ogr.Geometry(ogr.wkbMultiPoint)
    point = ogr.Geometry(ogr.wkbPoint)
    point.AddPoint(10,10)
    multipoint.AddGeometry(point)
    print(multipoint)

    point.AddPoint(20,20)
    multipoint.AddGeometry(point)
    print(multipoint)

    mp = multipoint.GetGeometryCount()
    print(mp)

    for mpx in range(multipoint.GetGeometryCount()):
        print(multipoint.GetGeometryRef(mpx))


    extfile = 'xx_data_pt.shp'
    if os.access(extfile,os.F_OK):
        driver.DeleteDataSource(extfile)
    #1、创建数据源
    newds = driver.CreateDataSource(extfile)
    #print(dir(newds))
    #print(dir(newds.CreateLayer))
    #2、创建数据源图层
    lyrn = newds.CreateLayer('point',None,ogr.wkbPoint)

    #3、定义图层字段,添加图层字段
    fieldcnstr = ogr.FieldDefn("idx",ogr.OFTInteger)
    lyrn.CreateField(fieldcnstr)

    fieldf = ogr.FieldDefn("namex",ogr.OFTString)
    lyrn.CreateField(fieldf)

    point_coors_arr = [[1,0],[2,0],[3,0],[4,0]]
    for idxx,point_coors in enumerate(point_coors_arr):
        #print(type(idxx))
        #print(type(point_coors))
        wkt = 'POINT (%f %f)' % (point_coors[0],point_coors[1])
        #print(wkt)
        geom = ogr.CreateGeometryFromWkt(wkt)
        
        feat = ogr.Feature(lyrn.GetLayerDefn())
        
        feat.SetField('idx',idxx)
        feat.SetField('namex','ID{0}'.format(idxx))
        
        feat.SetGeometry(geom)
        lyrn.CreateFeature(feat)
        
        #print(lyrn.GetLayerDefn())
        #print('idx:%i' % (idxx))
        #print("namex:%s" % 'ID{0}'.format(idxx))
        #x = 'ID{0}'.format(idxx)
        #print(x)
        """
        wkt = 'POINT (%f %f)' % (point_coors[0],point_coors[1])
        geom = ogr.CreateGeometryFromWkt(wkt)
        feat = ogr.Feature(lyrn.GetLayerDefn())
        feat.SetField('idx',idxx)
        feat.SetField('namex','ID{0}'.format(idxx))
        feat.SetGeometry(geom)
        lyrn.CreateFeature(feat)
        """
    newds.Destroy()



    extfile = 'xx_data_line.shp'
    driver = ogr.GetDriverByName("ESRI Shapefile")
    if os.access(extfile,os.F_OK):
        driver.DeleteDataSource(extfile)

    newds = driver.CreateDataSource(extfile)
    lyrn = newds.CreateLayer('line',None,ogr.wkbLineString)

    #字段定义创建
    fieldcnstr = ogr.FieldDefn("id",ogr.OFTInteger)
    fieldf = ogr.FieldDefn("name",ogr.OFTString)
    lyrn.CreateField(fieldcnstr)
    lyrn.CreateField(fieldf)

    point_coors_arr = [[0,0,1,2,3,-2,6,0]]
    #print(point_coors_arr)
    #print(type(point_coors_arr))
    #print(len(point_coors_arr))

    for idx,point_coors in enumerate(point_coors_arr):
        #wkt = 'LINESTRING(%f %f,%f %f,%f %f,%f %f)' % (point_coors[len(point_coors_arr) - len(point_coors_arr)],point_coors[len(point_coors_arr) - len(point_coors_arr) + 1],)
        wkt = 'LINESTRING(%f %f,%f %f,%f %f,%f %f)' % (point_coors[0],point_coors[1],point_coors[2],point_coors[3],point_coors[4],point_coors[5]
        ,point_coors[6],point_coors[7])
        print(wkt)
        geom = ogr.CreateGeometryFromWkt(wkt)
        feat = ogr.Feature(lyrn.GetLayerDefn())
        feat.SetField('id',idx)
        feat.SetField('name','line_one')
        feat.SetGeometry(geom)
        lyrn.CreateFeature(feat)
        
    newds.Destroy()




    extfile = 'xx_data_polygon.shp'
    driver = ogr.GetDriverByName('ESRI Shapefile')
    if os.access(extfile,os.F_OK):
        driver.DeleteDataSource(extfile)
    #创建数据源文件
    newds = driver.CreateDataSource(extfile)
    #创建几何形状图层
    lyrn = newds.CreateLayer('polygon',None,ogr.wkbPolygon)
    #定义字段
    fieldcnstr = ogr.FieldDefn('id',ogr.OFTInteger)
    fieldf = ogr.FieldDefn('name',ogr.OFTString)
    #图层添加字段
    lyrn.CreateField(fieldcnstr)
    lyrn.CreateField(fieldf)

    wkt_polygon_1 = 'POLYGON((2 1,12 1,12 4,2 4,1 2))'
    wkt_polygon_2 = 'POLYGON((4 1,8 1,8 3,4 3,3 1))'
    wkt_polygon_3 = 'POLYGON((8 4,10 4, 10 5,8 5,6 4))'
    #print(type(wkt_polygon_1))
    point_coors_arr = [wkt_polygon_1,wkt_polygon_2,wkt_polygon_3]
    #print(type(point_coors_arr))
    for idx,point_coors in enumerate(point_coors_arr):
        #print(idx)
        #print(point_coors)
        wkt = point_coors
        #使用wkt创建几何图形
        geom = ogr.CreateGeometryFromWkt(wkt)
        #获取图层要素  ogr.GetLayerDefn , ogr.Feature()
        feat = ogr.Feature(lyrn.GetLayerDefn())
        feat.SetField('id',idx)
        print('poly_{idx}'.format(idx = idx))
        #feat.SetField('name','poly_{idx}'.format(idx = idx))
        feat.SetField('name','poly_{idx}'.format(idx = idx))
        feat.SetGeometry(geom)
        lyrn.CreateFeature(feat)
        
    newds.Destroy()


    from osgeo import ogr
    import os,math
    inshp = "xx_data_polygon.shp"
    ds = ogr.Open(inshp)  #打开shp源文件
    driver = ogr.GetDriverByName("ESRI Shapefile")

    outputfile = "xx_data_polygon_copy.shp"   #输出shp
    if os.access(outputfile,os.F_OK):
        driver.DeleteDataSource(outputfile)

    pt_cp = driver.CopyDataSource(ds,outputfile)
    pt_cp.Release()


    from osgeo import ogr
    import os,math
    inshp = 'xx_data_polygon.shp'
    ds = ogr.Open(inshp)
    driver = ogr.GetDriverByName("ESRI Shapefile")
    outputfile = 'cp_polygon.shp'
    if os.access(outputfile,os.F_OK):
        driver.DeleteDataSource(outputfile)
        
    pt_cp = driver.CopyDataSource(ds,outputfile)
    pt_cp.Release()

    outputfile = 'cp2.shp'
    if os.access(outputfile,os.F_OK):
        driver.DeleteDataSource(outputfile)
    newds = driver.CreateDataSource(outputfile)
    layer = ds.GetLayer()
    pt_layer = newds.CopyLayer(layer,'xxx')
    #newds.Destroy()

    outputfile = 'cp3.shp'
    if os.access(outputfile,os.F_OK):
        driver.DeleteDataSource(outputfile)

    newds = driver.CreateDataSource(outputfile)
    layernew = newds.CreateLayer('worldcopy',None,ogr.wkbLineString)
    layer = ds.GetLayer()
    feature = layer.GetNextFeature()
    if feature is not None:
        layernew.CreateFeature(feature)
        feature = layer.GetNextFeature()
        
    newds.Destroy()


    driver = ogr.GetDriverByName("ESRI Shapefile")

    inshp = 'xx_data_polygon.shp'
    ds = ogr.Open(inshp)


    outf = 'cxp.shp'
    if os.access(outf,os.F_OK):
        driver.DeleteDataSource(outf)
        print("exists")
    newds = driver.CreateDataSource(outf)
    layernew = newds.CreateLayer('worldcopy',None,ogr.wkbLineString)

    layer = ds.GetLayer()

    #print(layer)
    feature = layer.GetNextFeature()
    print(feature)
    while feature is not None:
        layernew.CreateFeature(feature)
        feature = layer.GetNextFeature()
    newds.Destroy()
    '''

    from osgeo import ogr
    ds = ogr.Open('convChk.shp')
    layer = ds.GetLayer(0)
    spatialRef = layer.GetSpatialRef()
    print(spatialRef)

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  • 原文地址:https://www.cnblogs.com/ruiy/p/11996088.html
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