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The following script was written with the goal of taking a raster file, importing into a ArcGIS database and creating several deliverables from it. All aspects of the script/tool are working except for the handling if the output file name exists. I don't want to overwrite as it could lead to problems if others are using this script. The solution I came up with was to append a '_i' to the output file name if the output path exists, with i=1 initially but i+=1 as long as the path exists until it reaches a file name that doesn't exist.

The problem seems to be when I use the functions GDBFCinc() (for items in a geodatabase that don't require an extension) or 'fileinc()' (for items that do require an extension) the script seems to ignore them. However, when I use their contents, i.e. not calling the function, but copying the contents and manually putting the variable in each spot, the output file increments correctly. As such I think I am calling the function wrong or in someway have defined it improperly. This is an early foray into using functions/modules so clearing up what I am doing wrong will help in the long run.

import arcpy, sys, os, fnmatch
from arcpy.sa import *
from datetime import datetime

#These functions had been in separate module, however, for trouble shooting purposes brought here. 
def GDBFCinc(n):
    '''Uses arcpy to check if a file path already exists and increments a numerical suffix until it does not. Works on Geodatbases.'''
    if not arcpy.Exists(n):
        pass
    else:
        i=1
        n = "{}_{}".format(n,i)
        while arcpy.Exists(n):
            i+=1
            n = "{}_{}".format(n,i)

def fileinc(n):
    '''Checks if a file path already exists and increments a numerical suffix before the file extension until it does not.'''
    if not os.path.exists(n):
        pass
    else:
        filename, file_extension = os.path.splitext(n)
        i=1
        n = "{}_{}{}".format(filename,i,file_extension)
        while arcpy.Exists(n):
            i+=1
            n = "{}_{}{}".format(filename,i,file_extension)

#This code is intended to go through each region and:
#1.Take the .ASC bathy surface dictated by user input and import it into the MBES Geodatabase with the client desired name and user dictated suffix
#2.Clip it to the regional polygon and create bilinear pyramids for that grid.
#3.Output that clipped file to ASC grid to the client data folder.
#4.Create 4 seperate hillshades and bilinear pyramids for those hillshades
#5.Create Aspect and Slope Grids and bilinear pyramids for those grids.
#6.Calculate Focal Statistics.
#7.Calculate 20m and 100m Contours.

#Set tool input parameters.
#Input Grid, File path,.
MBESRawPath = arcpy.GetParameterAsText(0)
#Region input, string.
region = arcpy.GetParameterAsText(1)
#Leg input, String
leg = arcpy.GetParameterAsText(2)
#User dicated Suffix, string.
SUF = arcpy.GetParameterAsText(3)
#Polygon for Clip, File Path.
poly = arcpy.GetParameterAsText(4)

#File Location Dictionary to be called based on region input value. Used for both root directory and clip polygon if no user input.
Rootdict = {"TG_Root":"D:\\J18350-TGS-WestAfrica\\Client\\GIS\\Geodatabases\\The-Gambia\\" , "TG_Poly":"A:\\J18350-TGS-WestAfrica_Leg_3\\Client\\GIS\\Shapefiles\\RegionalClippingBoundaries\\TG_ClippingPolygon.shp" , "GB_Root" : "D:\\J18350-TGS-WestAfrica\\Client\\GIS\\Geodatabases\\Guinea_Bissau\\", "GB_Poly" : "A:\\J18350-TGS-WestAfrica_Leg_2\\Client\\GIS\\Shapefiles\\RegionalClippingBoundaries\\GB_ClippingPolygon.shp", "AGC_Root" : "D:\\J18350-TGS-WestAfrica\\Client\\GIS\\Geodatabases\\AGC\\", "AGC_Poly" : "A:\\J18350-TGS-WestAfrica_Leg_2\\Client\\GIS\\Shapefiles\\RegionalClippingBoundaries\\AGC_ClippingPolygon.shp", "SN_Root": "D:\\J18350-TGS-WestAfrica\\Client\\GIS\\Geodatabases\\Senegal-North\\", "SN_Poly": "A:\\J18350-TGS-WestAfrica_Leg_2\\Client\\GIS\\Shapefiles\\RegionalClippingBoundaries\\SN_ClippingPolygon.shp", "SS_Root" :"D:\\J18350-TGS-WestAfrica\\Client\\GIS\\Geodatabases\\Senegal-South\\", "SS_Poly" : "A:\\J18350-TGS-WestAfrica_Leg_2\\Client\\GIS\\Shapefiles\\RegionalClippingBoundaries\\SS_ClippingPolygon.shp"}
root = Rootdict[region + '_Root']

#Setup for user input suffix. Uses user input, prepending a '_', if user input = date then output current date, if no user input, = ""(blank).
date_object = datetime.now()
if SUF != "":
    Suffix = "_" + SUF
elif SUF == "date":
    Suffix = "_" + date_object
else:
    Suffix = ""

#Set up for user input poly. Uses user input file path or defaults to regional polygon if no user input.
if poly != "":
    clippoly = poly
else:
    clippoly = Rootdict[region + "_Poly"]

#Get the file name from the input path and parse it so the 'infile' variable = the file name with no extension .
T = ""
infilepath = os.path.split(MBESRawPath)
tmp = infilepath[-1].split(".")
infile = tmp[0]

#Create variables for various file paths.
MBESGDBPath = root + region + "_MBES_Bathymetry_Mosaics.gdb\\"
MBESOUTPATH =  "A:\\J18350-TGS-WestAfrica_Leg_" + leg + "\\Client\\Data\\MBES_Processed\\Bathymetry\\" + region + "\\"
MBESOUTFILENAME = MBESOUTPATH + "Mosaic_EM302_Bathymetry_15m" + Suffix + ".asc"
AspectFile = MBESGDBPath + "Mosaic_EM302_Aspect_15m" + Suffix
SlopeFile = MBESGDBPath + "Mosaic_EM302_Slope_15m" + Suffix
GDBFileName = MBESGDBPath + T + infile

#Check if file name begins with a number, if so the output file in the geodatabase will begin with T (ArcGIS quirk) and that needs to be reflected when referencing it.
numbers = "0123456789"
if infile[0] in numbers:
    T = "T"
else:
    T = ""


#Import user input raster to geodatabase
arcpy.RasterToGeodatabase_conversion(MBESRawPath, MBESGDBPath)

#Get Poly extents from the raster itself for use in the clipping process.
extent = arcpy.Describe(clippoly)
rectangle = str(extent.extent)

#Make 'bathyfile' variable that uses the earlier constructed current regions database path plus the client desired file name.
bathyfile = MBESGDBPath + "Mosaic_EM302_Bathymetry_15m" + Suffix
#Use GDBFCinc to increment 'bathyfile' if path exists in geodatabase to avoid overwrite error.
GDBFCinc(bathyfile)

#Clip imported raster to the current regions polygon.
arcpy.Clip_management(GDBFileName, rectangle, bathyfile, clippoly, 255 , "ClippingGeometry")
arcpy.BuildPyramids_management(bathyfile,"-1", "NONE", "BILINEAR", "DEFAULT","","")

#Increment 'MBESOUTFILENAME' if path exists in output directory. 
fileinc(MBESOUTFILENAME)
arcpy.RasterToASCII_conversion(bathyfile, MBESOUTFILENAME)

#Create variables for the hillshade file names so the can be manipulated more easily
H1 = MBESGDBPath + "Mosaic_EM302_Hillshade_Az315_Alt25_15m" + Suffix
H2 = MBESGDBPath + "Mosaic_EM302_Hillshade_Az225_Alt25_15m" + Suffix
H3 = MBESGDBPath + "Mosaic_EM302_Hillshade_Az135_Alt25_15m" + Suffix
H4 = MBESGDBPath + "Mosaic_EM302_Hillshade_Az45_Alt25_15m" + Suffix

#Create 4 different hillshades per the clients request. Build pyramids for each hillshade
GDBFCinc(H1)
arcpy.HillShade_3d(bathyfile, H1 , 315,25)
arcpy.BuildPyramids_management(H1,"-1", "NONE", "BILINEAR", "DEFAULT","","")
GDBFCinc(H2)
arcpy.HillShade_3d(bathyfile, H2 , 225,25)
arcpy.BuildPyramids_management(H2,"-1", "NONE", "BILINEAR", "DEFAULT","","")
GDBFCinc(H3)
arcpy.HillShade_3d(bathyfile, H3, 135,25)
arcpy.BuildPyramids_management(H3,"-1", "NONE", "BILINEAR", "DEFAULT","","")
GDBFCinc(H4)
arcpy.HillShade_3d(bathyfile, H4 , 45,25)
arcpy.BuildPyramids_management(H4,"-1", "NONE", "BILINEAR", "DEFAULT","","")

#Create Aspect and pyramids
GDBFCinc(AspectFile)
arcpy.Aspect_3d(bathyfile, AspectFile)
arcpy.BuildPyramids_management(AspectFile, "-1", "NONE", "BILINEAR", "DEFAULT","","")

# Create Slope Surface and pyramids
GDBFCinc(SlopeFile)
arcpy.Slope_3d(bathyfile, SlopeFile )
arcpy.BuildPyramids_management(SlopeFile, "-1", "NONE", "BILINEAR", "DEFAULT","","")

#Create Focal Stat surface for generating contours
outFocalStat = FocalStatistics(bathyfile, NbrRectangle(20,20,"CELL"),"MEAN","DATA")
outFocalStat.save(MBESGDBPath + "BathyFocalStats_1" + Suffix)

#Create 20m and 100m Contours
arcpy.Contour_3d(MBESGDBPath + "BathyFocalStats_1", MBESGDBPath + "Mosaic_EM302_BathymetryContours_20m" + Suffix, 20)
arcpy.Contour_3d(MBESGDBPath + "BathyFocalStats_1", MBESGDBPath + "Mosaic_EM302_BathymetryContours_100m" + Suffix, 100)


print "Complete"

I have been working on the lack of return. This is what I have so far, Still not working properly (not incrementing when file exists).

def GDBFCinc(n):
    '''Uses arcpy to check if a file path already exists and increments a numerical suffix until it does not. Works on Geodatbases.'''
    if not arcpy.Exists(n):
        pass
    else:
        i=1
        n = "{}_{}".format(n,i)
        while arcpy.Exists(n):
            i+=1
            n = "{}_{}".format(n,i)
    return n
def fileinc(n):
    '''Checks if a file path already exists and increments a numerical suffix before the file extension until it does not.'''
    if not os.path.exists(n):
        pass
    else:
        filename, file_extension = os.path.splitext(n)
        i=1
        n = "{}_{}{}".format(filename,i,file_extension)
        while arcpy.Exists(n):
            i+=1
            n = "{}_{}{}".format(filename,i,file_extension)
    return n
  • You have posted to much code if the problem is only the functions. Start by not combining path using +, instead use os.path.join. Your function is not returning anything, so they will return None by default – BERA May 1 at 15:19
  • Main issue I see is no return value and related variable assignment. Will elaborate in answer. – smiller May 1 at 15:19
  • Bera, apologies on too much code. I was unsure if something in the way i was calling the function or otherwise could be the problem. – ckhartma621 May 1 at 15:28
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To transfer data outside of a function definition, you need to use return with a value (or global variables, which are not pythonic and not recommended in most cases). For more see here:

It looks like you are wanting to change the value of the variable H1 based on the output from GDBFCinc. To do that, add a return to GDBFCinc, and assign the result of GDBFCinc(H1) to a variable, such as H1.

e.g.

def GDBFCinc(n):
    '''Uses arcpy to check if a file path already exists and increments a numerical suffix until it does not. Works on Geodatbases.'''
    if not arcpy.Exists(n):
        pass
    else:
        i=1
        n = "{}_{}".format(n,i)
        while arcpy.Exists(n):
            i+=1
            n = "{}_{}".format(n,i)
    return n

and

H1 = GDBFCinc(H1)

Similarly, add a return to fileinc, although I don't see that function referenced in your code snippet so can't advise whether it's being called properly.

  • @smilller. Your input was valuable and the function is now being called. However, instead of replacing the "_1" at the end of the file name, it is appending the incremented suffix i.e. "_1_2_3...). I find this strange, because again, when I Implement the body of the function directly in the code it works ("_1" replaced with "_2"). Could you give some insight as to what I might be doing wrong or maybe set me down the right path to fixing this? – ckhartma621 May 4 at 14:29
  • You are saving n to check against the list of filenames, then returning n (name_2_3). Save the basename separately and increment the name to check based on the basename + _x. – smiller May 5 at 12:29

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