Geog 491: Exercise 9- Create a Script Tool

Goal and Background

The goal of this exercise is to create a custom script tool.  The tool will generate a swiss hillshade.  A swiss hillshade is a slightly modified hillshade.  It uses several different filters to generate the terrain.  Below are the objectives for this exercise:

• Set the up the script.
• Set up the parameters using the “GetParatermersAsText” option.
• Set local variables.
• Set up a try except loop for the calculation of the hillshade.
• Add the workflow to the loop: divide the DEM, calculate a hillshade, run focal statistics, and add the DEM.
• Set up the except statement to print and error message.
• Create a custom toolbox.
• Use the Add Script Wizzard to add a custom script tool.
• Test your tool.

Methods

The regular parameters were set up to start the script.  Simple parameters were set up using GetParameterAsText.  Then the loops were set up.  A DEM from a previous exercise was created in order to produce the map in the resuts below.

Results

Below is the swiss hillshade created from the script and also the script that was created for this exercise.

#-------------------------------------------------------------------

# Name:        Exercise 9- Create a script tool

# Purpose:      To create a custom script tool.  The tools will generate a swiss hillshade

#

# Author:      Laura Hartley, hartlelj

#

# Date:         8/4/2016

#-------------------------------------------------------------------

#Ensure the program is working

print "Script initialized"

#import system modules

import os

import shutil

import time

import datetime

#Import arcpy module

import arcpy

from arcpy import env

from arcpy.sa import*

from arcpy.ddd import *

arcpy.env.overwriteOutput = True

arcpy.CheckOutExtension('3D')

arcpy.CheckOutExtension('spatial')

#Objective two

input_DEM = arcpy.GetParameterAsText(0)

scratchPath = arcpy.GetParameterAsText(1)

fileName = arcpy.GetParameterAsText(2)

filtered_Hillshade = arcpy.GetParameterAsText(3)

aerial_Perspective = arcpy.GetParameterAsText(4)

#Objective three

Z_factor = "1"

print "Creating local variables!" ,datetime.datetime.now().strftime("%H:%M:%S")

#Local variables:

divide_By = "5"

dEM_div_5 = os.path.join(scratchPath,fileName) +"_divHS"

default_Hillshade = os.path.join(scratchPath,fileName) +"_HS"

#Objective four

try:

    #Objective five, process: divide

    print "dividing input DEM by 5" ,datetime.datetime.now().strftime("%H:%M:%S")

    arcpy.Divide_3d(input_DEM,divide_By,dEM_div_5)

    #Process: Hillshade

    print "Create default hillshade" ,datetime.datetime.now().strftime("%H:%M:%S")

    arcpy.HillShade_3d(input_DEM,default_Hillshade,"315","45","NO_SHADOWS",Z_factor)

    #Process: Focal statistics

    print "Create a median filter for the hillshade effect" ,datetime.datetime.now().strftime("%H:%M:%S")

    outFocalStatistics = FocalStatistics(default_Hillshade,NbrRectangle(4,4,"CELL"),"MEDIAN","NODATA")

    outFocalStatistics.save(filtered_Hillshade)

    #Process: plus

    print "Add the divided dem to the default hilshade, creating an aerial perspective" ,datetime.datetime.now().strftime("%H:%M:%S")

    arcpy.Plus_3d(dEM_div_5,default_Hillshade,aerial_Perspective)

    print "The script is complete"

#Objective six

except:

    #report an error message

    arcpy.AddError("Something didn't work")

    #report any error messages it might have generated

    arcpy.AddMessage(arcpy.GetMessages(2))