So I have 490 point fc's in a single directory with uniform spatial features, field names/datatypes. I'm trying to figure out how to consecutively input the first seven fc's into the merge tool, create a new merged fc, and then iterate the model until 70 new merged fc's are created.

I know how to iterate single fc's as input into a tool, but not multiple features per x number of iterations.

I have some code below that uses list, an array, and a count system that does what i need for another GP operation. How can I translate this into modelbuilder's variables/methods? I am using modelbuilder because I was having trouble mapping fields for merge in python

    # Create list of rasters
    rasters = arcpy.ListRasters("*", "tif")
    rastersCount = len(rasters)

    counter = 0
    weekNum = 1

    while counter < rastersCount:
        #collect 7 consecutive rasters
        weekRasters = []
        for i in range(counter,(counter+7)):

        # Execute CellStatistics (one can use list of rasters directly here)
        outCellStatistics = CellStatistics(weekRasters, "SUM", "NODATA")
        # Save the output
        outRasterName = "week_"+ str(weekNum)
        outCellStatistics.save("D:/dailyrainfall/nueces_dailyrainfall_rasterized/" + outRasterName )

        counter += 7
        weekNum += 1
    # If an error occurred while running a tool, then print the messages.
    print arcpy.GetMessages()

Using ArcGIS 10 (ArcInfo) SP4 with all extensions

2 Answers 2


I'm not sure you can transfer that type of logic to modelbuilder. But are you aware that you can wire up a script to a model builder tool? Why bother with any thing else as you have the framework of logic in your existing script (it just needs tweaking)? Once you add your script as a "tool script" it looks and behaves like any other geoprocessing tool.

  • the only reason i'm using modelbuilder is because I was having trouble mapping fields for merge in python Commented Apr 22, 2012 at 20:26
  • 2
    There's no mention of that issue in the original question. Would it be possible for you to re-phrase your question to more accurately describe what you are trying to do, please? For example, your code does not mention Merge so my preference would be to see some that does.
    – PolyGeo
    Commented Apr 23, 2012 at 0:02

I couldn't get it to work with modelbuilder, but spent a few days modifying the code provided in the original post. Although this code isn't complex, it is for some without much experience. I hope others can profit by the time I spent crunching away.

# merge 7 consecutive feature classes, sum one field, 
# sort the summed field ascending, and delete identical features
# 4/29/2012

import arcpy
from arcpy import env

# Set workspace
env.workspace = "C:/nueces_dailyrainfall_sorted/2009/2nd/"

# Allow overwrites
arcpy.env.overwriteOutput = True

    # Create list of feature classes
    fcs = arcpy.ListFeatureClasses()
    fcsCount = len(fcs)

    counter = 0
    weekNum = 1

    while counter < fcsCount:
        #collect 7 consecutive feature classes
        weekFeatures = []
        for i in range(counter,(counter+7)):

        # local variables
        path = "C:/nueces_dailyrainfall_sorted/2009/2nd/" 
        outFeatureName = "week_"+ str(weekNum)
        outStatsTable = "week_"+ str(weekNum)+ "_summary"

        caseField = "Id"
        joinField = "Id"
        statsFields = [["Globvalue", "SUM"]]
        identField = ["Id"]

        # Execute Merge
        arcpy.Merge_management(weekFeatures, outFeatureName)

        # Execute Summary Statistics
        arcpy.Statistics_analysis(path+outFeatureName+".shp", path+outStatsTable+".dbf", statsFields, joinField)

        # Execute Join Field
        arcpy.JoinField_management(path+outFeatureName+".shp", joinField, path+outStatsTable+".dbf", joinField)

        # Sort by Sum_Globalvalue Ascending
        arcpy.Sort_management(path+outFeatureName+".shp", path+outFeatureName+"_sorted"+".shp", "Id ASCENDING", "UR")

        # Delete identical
        arcpy.DeleteIdentical_management(path+outFeatureName+"_sorted"+".shp", identField)

        counter += 7
        weekNum += 1
    # If an error occurred while running a tool, then print the messages.
    print arcpy.GetMessages()

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