Re: [Tutor] Creating a Polyline Feature class

[bob gailer]

On 3/3/2012 11:21 PM, Carie Pigeon wrote:

I have an assignment to create a polyline feature class of rhino tracks from a csv file. I am getting an error that says "unbound method add() must be called with Array instance as first argument (got type instance)". this is for line 104, the line I underlined and put in bold below in my code. What does this mean? If there are other obvious code issues, please feel free to comment. I am unsure if my code is correct. Thank you for your time!

Cheers,
Carie

# Reads rhino positions from an Excel-originating CSV file

import arcpy
from arcpy import env
import fileinput
import string
import os

env.overwriteOutput = True

# Hard code file paths
spreadsheet = "C:/WCGIS/Geog485/Lesson4/
RhinoObservations.csv"

# Sample of data
###Observer,X,Y,Rhino,Comments
##Ben,26.99391,-19.10447,Bo,
##Ben,27.00071,-19.1089,Tulip,Bathing
##Ben,26.9919,-19.10511,Bo,
##Ben,27.00071,-19.1059,Tulip,
##Ben,26.96809,-19.09578,Patches,
##Ben,26.97808,-19.11016,Dinky,
##Ben,26.99213,-19.10395,Bo,
##Ben,27.00083,-19.10326,Tulip,
##Ben,26.97038,-19.09863,Patches,Not doing much of anything
##Ben,26.97768,-19.11153,Dinky,
##Ben,26.99107,-19.10421,Bo,
##Ben,27.00138,-19.1021,Tulip,
##Ben,26.97122,-19.0991,Patches,
##Ben,26.97551,-19.11269,Dinky,
##Ben,26.9904,-19.10553,Bo,
##Ben,26.99893,-19.10342,Tulip,

# output feature class?? feature class doesn't exist yet, so not sure how to do this??

fcname = "C:/WCGIS/Geog485/Lesson4"
outname = "C:/WCGIS/Geog485/Lesson4/Rhino.shp"



# Open the CSV file & read the header line
observations = open(spreadsheet, "r")
headerline = observations.readline()
fieldList = headerline.split(",")

###     0    1 2   3      4
### Observer,X,Y,Rhino,Comments
# Look through the header to find "X", "Y" and the "Rhino" field indices
rhinoIndex = fieldList.index("Rhino")
xIndex = fieldList.index("X")
yIndex = fieldList.index("Y")
## print "Rhino "+str(rhinoIndex) +" X "+str(xIndex)+" Y "+str(yIndex)

# Create a list / array for RhinoTracks
rhinoTracks = {}

# create the output feature class

arcpy.CreateFeatureclass_management ("C:/WCGIS/Geog485/Lesson4", "Rhino.shp", "POLYLINE")

# open an insert cursor for the new feature class
cur = arcpy.InsertCursor(outname)

# Loop through the rest of the file to read in all of the rhinos
for line in observations.readlines():
    ##Ben,26.99391,-19.10447,Bo,
    segmentedLine = line.split(",")
    rhino = segmentedLine[rhinoIndex]
    #print rhino

# If rhino exists in dictionary - get the array from its key & add a point

    if rhino in rhinoTracks:
        coordArray = rhinoTracks[rhino]
        # create a new row or feature, in the feature class


        ## coordArray { [x,y] }
        lineArray = arcpy.Array()
        coord = arcpy.Point

I am making educated guesses - try coord = arcpy.Point()

        coord.X = segmentedLine[xIndex]
        coord.Y = segmentedLine[yIndex]
        ## add point to coordinate array
        coordArray.add(coord)

#print "Rhino is "+rhino+" added point "+str(segmentedLine[xIndex])+" "+str(segmentedLine[yIndex])

        ## coordArray { [x,y],[x1,y1] }

        feat = cur.newRow()

        # set the geometry of the new feature to the array of points
        feat.shape = lineArray

        #insert the feature
        cur.insertRow(feat)
        lineArray.removeAll()
        lineArray.add(coord)

# If rhino doesn't exist in dictionary - make a new array & add a point

    else:

        cur = arcpy.InsertCursor(outname)
        ## Create a coordinate array
        coordArray = arcpy.Array

try coordArray = arcpy.Array()

        ## Create a point object
        coord = arcpy.Point

also try coord = arcpy.Point()

        coord.X = segmentedLine[xIndex]
        coord.Y = segmentedLine[yIndex]
        ## add point to coordinate array
*_coordArray.add(coord)

_*        feat = cur.newRow()

        # set the geometry of the new feature to the array of points
        feat.shape = lineArray

        #insert the feature
        cur.insertRow(feat)
        lineArray.removeAll()
        lineArray.add(coord)
        ## add coordinate array to my Dictionary (list of rhinos)
        rhinoTracks[rhino] = coordArray

Do you understand the difference between
coord = arcpy.Point
and
coord = arcpy.Point()
?

The first gets you a reference to the class.
The 2nd gets you an instance of the class.
Quite different.

--
Bob Gailer
919-636-4239
Chapel Hill NC


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