I am creating a shapefile based on three columns in my CSV File - Latitude, Longitude, and Laps. For the most part, I understand how to loop through the data and create the many points based on the latitude and longitude column, but I am having issues with my Laps column. I need to be able to loop through the data but exclude blank columns. Below is a sample of my data from the CSV File. The row that needs to be excluded is the row with the total Lap time for that Lap (i.e. #Lap 0...)

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Below is my code that I am using. When I run it, I get an Error 99999: Something unexpected has caused the tool to fail.

# This script reads GPS tracks in CSV format and
# writes the geometries (polyline) from the list of coordinate pairs

import csv
import arcpy

def addPolyline(fc, array, sr):
    polyline = arcpy.Polyline(array, sr)
    with arcpy.da.InsertCursor(fc, ("SHAPE@",)) as cursor:

# setup workpace to save the file
arcpy.env.workspace = r"C:\\"

# setup the feature class and spatial reference 
polylineFC = "carpath.shp"
sr = arcpy.SpatialReference("GCS_WGS_1984")
arcpy.CreateFeatureclass_management(arcpy.env.workspace, polylineFC, "POLYLINE", spatial_reference = sr)
spatialref = arcpy.Describe(polylineFC).spatialReference

# open the input file
wakefieldRaceWay = open (arcpy.env.workspace + "\WakefieldParkRaceway_20160421.csv", "r") 
# setup csv reader and process the header
csvReader = csv.reader(wakefieldRaceWay)
header = next(csvReader)

latIndex = header.index("Latitude")
lonIndex = header.index("Longitude")
lapIndex = header.index("Lap")

# create an array
vertices = arcpy.Array()

# create a loop to iterate over lines but 
# exclude lines that have zero data in them
for row in csvReader:
    isLap = row[lapIndex]
    if isLap == '\n':
        if vertices.count> 0 :
            addPolyline(polylineFC, vertices, spatialref)
    # Loop through the lines in the file and get each coordinate 
    # put the coordinates into a tuple and add it to the list
    Latitude = row[latIndex]
    Longitude = row[lonIndex]
    vertex = arcpy.Point(Latitude, Longitude)
# add the last segment manually    
addPolyline(polylineFC, vertices, spatialref)
arcpy.env.workspace = r"C:\\"

using a raw string, the interpreter will escape backslashes, so this will result in 4 backslashes. Remove the "r" as you have to escape to form a valid string.

>>> dir = r"c:\\"
>>> dir

here you are also prepending a backslash to the file name, so this will end up with 5 slashes.

wakefieldRaceWay = open (arcpy.env.workspace + "**\**WakefieldParkRaceway_20160421.csv", "r") 

>>> wakefieldRaceWay = dir + "\WakefieldParkRaceway_20160421.csv"
>>> wakefieldRaceWay

an empty value in a csv will be blank, not a new line character

if isLap == '\n':

so use

 if isLap in (None, "") 

or better yet

if not isLap 

EDIT: You need some logic to skip attempting to create points from the blank lines lat/long.

# Loop through the lines in the file and get each coordinate 
# put the coordinates into a tuple and add it to the list
if isLap:
  Latitude = row[latIndex]
  Longitude = row[lonIndex]
  vertex = arcpy.Point(Latitude, Longitude)

Also you need to clear your vertices array after creating a new line or every line will include the vertices of every previous line.

if not isLap:
    if vertices.count> 0 :
        addPolyline(polylineFC, vertices, spatialref)
  • Thanks the problem was with the way I was calling the spatial reference. The problem I am not having and I get a RuntimeError: Point: Input value is not numeric. My coordinate system is decimal in degrees – buster Williams Apr 21 at 0:34
  • I think the problem is you are adding points using the lat/long from blank rows. – BlueTalon Apr 21 at 1:52
  • When I incorporate your changes, I am getting a new runtime error: Object: CreateObject cannot create geometry from inputs. Do you understand why or where? I have used the debugger and nothing. Even with the error, the shapefile is still created with the laps. – buster Williams Apr 22 at 2:51

I think you should look at this line of code:

arcpy.env.workspace = r"C:\\"

It does not look like a valid workspace so as a test try using:

arcpy.env.workspace = r"C:\temp"
  • It didn't work. My professor believes the problems lie in line 42: if isLap == '\n'. I told python to look for an empty cell instead of a cell that contains a blank, and that's why I am getting the error. He sent me this site: tutorialspoint.com/python/python_strings.htm. Do you know the proper string manipulation to use? – buster Williams Apr 20 at 22:56
  • Please always provide the full error message, including line number, along with the precise code you tested, in the body of your question. – PolyGeo Apr 20 at 22:59
  • 1
    I second using a directory in C: rather than the root, unless absolutely necessary. You will run into trouble eventually, if that isn't already an issue. Good habit to get into. – BlueTalon Apr 20 at 23:23

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