我有很多栅格图，然后我想用矢量图去切下栅格


import sys
sys.path.append('C:\Program Files(x86)\ArcGIS\Bin')
import arcgisscripting
gp = arcgisscripting.create()
gp.toolbox = "Data Management Tools"
yf = ['D:\\zb\\1998-9.tif','D:\\zb\\1999-9.tif','D:\\zb\\2000-9.tif']
im = ".img"
for letter in yf :

y= filter(lambda x:x.isdigit(),letter)
result_shp = "D:\\rasterclip1\\clip"+str(y)+im  
gp.Clip_management(letter,"116.765003 45.710870 130.16309 54.116341","result_shp","D:\\zzj\\lkalbers.shp","255","ClippingGeometry")

报错如下
Traceback (most recent call last):
  File "C:\Users\myidream\Desktop\new  1.txt", line 12, in <module>
    gp.Clip_management(letter,"116.765003 45.710870 130.163096 54.116341","result_shp","D:\\zzj\\lkalbers.shp","255","ClippingGeometry")
ExecuteError: ERROR 999999: Error executing function.
Failed to execute (Clip).



求大神指点