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Код: Выделить всё

# DissolveByUnique.py
# Description: Divide a line geodatabase feature class into several based on the unique values in a 
#              field.  Output will be dissolved to remove pseudonodes (if any).
# Author: ESRI
# Date: 1/1/04

import arcgisscripting, sys, string, os
gp = arcgisscripting.create()

try:
    # Set the workspace (to avoid having to type in the full path to the data every time)
    gp.workspace = "C:/data/Transportation.mdb"

    # Set the input feature class    
    fc = "transport"

    # Set the field to create a list of unique values    
    fieldname = "ROAD_CLASS"

    # Open a Search Cursor to identify all unique values
    rows = gp.SearchCursor(fc)
    row = rows.Next()

    # Set a list variable to hold all unique values
    L = []

    # Using a while loop, cursor through all records and append unique values to the list variable
    while row:
        value = row.GetValue(fieldname)
        if value not in L:
            L.append(value)
        row = rows.Next()

    # Sort the list variable
    L.sort()

    # If a value in the list variable is blank, remove it from the list variable
    if ' ' in L:
        L.remove(' ')

    # Use MakeFeatureLayer to create a selectable layer
    gp.MakeFeatureLayer(fc, "dissolveLYR")

    # Loop through the list variable
    x = 0
    for item in L:

        # Concatenate the query
        query = "[" + fieldname + "]" + " = '" + L[x] + "'"

        # Create a selection on the layer with the current unique value (i.e., L[x])
        gp.SelectLayerByAttribute("dissolveLYR", "NEW_SELECTION", query)

        # Use Dissolve to create new feature class based on layer selection, output feature class 
        # will share name of unique value 
        gp.Dissolve_management("dissolveLYR", L[x], fieldname)
        x = x + 1

except:
    # If an error occurred while running a tool print the messages
    print gp.getmessages()