geoTools.py 文件源码

def exporttogeojson(geojsonfilename, buildinglist):
    #
    # geojsonname should end with .geojson
    # building list should be list of dictionaries
    # list of Dictionaries {'ImageId': image_id, 'BuildingId': building_id, 'polyPix': poly,
    #                       'polyGeo': poly}
    # image_id is a string,
    # BuildingId is an integer,
    # poly is a ogr.Geometry Polygon
    #
    # returns geojsonfilename

    driver = ogr.GetDriverByName('geojson')
    if os.path.exists(geojsonfilename):
        driver.DeleteDataSource(geojsonfilename)
    datasource = driver.CreateDataSource(geojsonfilename)
    layer = datasource.CreateLayer('buildings', geom_type=ogr.wkbPolygon)
    field_name = ogr.FieldDefn("ImageId", ogr.OFTString)
    field_name.SetWidth(75)
    layer.CreateField(field_name)
    layer.CreateField(ogr.FieldDefn("BuildingId", ogr.OFTInteger))

    # loop through buildings
    for building in buildinglist:
        # create feature
        feature = ogr.Feature(layer.GetLayerDefn())
        feature.SetField("ImageId", building['ImageId'])
        feature.SetField("BuildingId", building['BuildingId'])
        feature.SetGeometry(building['polyPix'])

        # Create the feature in the layer (geojson)
        layer.CreateFeature(feature)
        # Destroy the feature to free resources
        feature.Destroy()

    datasource.Destroy()

    return geojsonfilename