topic Re: Python script to alter XY values for a feature in Geoprocessing Questions

Python script to alter XY values for a feature

JosephSheffield — Thu, 09 Sep 2010 22:26:32 GMT

I have a python script for Arc 10 that is attempting to alter the X and Y values for a feature in a feature class. I am able to get the value of the points.X and point.Y and alter these values. But, I can't figure out how to get the change to be saved in the feature class once the script is completed.

Here is the code:

# Import arcpy module
import arcpy
 
arcpy.env.overwriteOutput = True

# Script arguments
Dgb2_A = arcpy.GetParameterAsText(0)
Fault_Reconstruction = arcpy.GetParameterAsText(1)


# Local variables:
A_TIM = "C:\\Alamo_Project\\Alamo_Breccia.mdb\\Measured_Sections\\A_TIM"
numFeatures = 0
numFeatures = arcpy.GetCount_management(Fault_Reconstruction)
# Process: Select Layer By Attribute
arcpy.SelectLayerByAttribute_management(Fault_Reconstruction, "NEW_SELECTION", "[OBJECTID] = 1")
# Process: Select Layer By Location
arcpy.SelectLayerByLocation_management(Dgb2_A, "INTERSECT", Fault_Reconstruction, "", "NEW_SELECTION")
# Process: Copy Features
arcpy.CopyFeatures_management(Dgb2_A, A_TIM, "", "0", "0", "0")
inputFieldX = "Fault_Movement_X"
inputFieldY = "Fault_Movement_Y"
cur = arcpy.SearchCursor(Fault_Reconstruction)
MovementX = 0
MovementY = 0
currentRow = 0
for row in cur:
    MovementX = row.getValue(inputFieldX)
    MovementY = row.getValue(inputFieldY)
    arcpy.AddMessage("X: " + str(MovementX))
    arcpy.AddMessage("Y: " + str(MovementY))
    row = cur.next()
curA = arcpy.UpdateCursor(A_TIM)
shapefieldname = arcpy.Describe(A_TIM).shapeFieldName
pnt = arcpy.Point()
newpnt = arcpy.Point()

tempX = 0
tempY = 0


for row in curA:
    feat = row.getValue(shapefieldname)
    pnt = feat.getPart()
    arcpy.AddMessage("X: " + str(pnt.X))
    arcpy.AddMessage("Y: " + str(pnt.Y))
    pnt.X = pnt.X + MovementX
    pnt.Y = pnt.Y + MovementY
    arcpy.AddMessage("X: " + str(pnt.X))
    arcpy.AddMessage("Y: " + str(pnt.Y))
    curA.updateRow(row)

Re: Python script to alter XY values for a feature

KimOllivier — Fri, 10 Sep 2010 12:57:45 GMT

To update the shape field you have to create an array and assign it to the shape in the buffer before you write the buffer out. You have created a pnt object and updated that, but have not written it back into the row. If the feature is a polyline or polygon then the object needs to be an array of arrays of points to handle multiparts.

row.feat = pnt
curA.updateRow(row)

Also in your search cursor you are mixing the old and new methods, the for loop automatically interates the cursor.

either
row = cur.next()
while row :
.... process
....row = cur.next()

or
for row in cur :
....process

Re: Python script to alter XY values for a feature

JosephSheffield — Fri, 10 Sep 2010 14:52:47 GMT

kimo

Thanks for the input. When I add the row.feat = pnt I get the following error: "<type 'exceptions.RuntimeError'>: ERROR 999999: Error executing function.
Failed to execute (FaultRecTest)."

I also tried feat = pnt. This script runs, but does not alter the location of the feature.

Thanks for pointing out that I was mixing old and new methods for the search cursor. I've only have begun to play with python and C# code for Arc 10.