HowTo: Create a line based on origin and destination points with Python

Article ID:	31879
Software:	ArcGIS - ArcEditor 9.0, 9.1, 9.2, 9.3, 9.3.1 ArcGIS - ArcInfo 8.1.2, 8.2, 8.3, 9.0, 9.1, 9.2, 9.3, 9.3.1 ArcGIS - ArcView 9.0, 9.1, 9.2, 9.3, 9.3.1
Platforms:	N/A

Summary

Instructions provided demonstrate one method for creating a line feature between origin and destination point XY coordinates from a table using the Python scripting environment.

Procedure

This article contains a sample table and script that demonstrates one method for creating a line feature between an origin and destination point XY coordinates from a table.

The script creates a feature class, defines the coordinate system and then uses the information provided in the table to populate the feature class with the line geometries in ArcGIS 9.2 or higher release:

import sys, string, os, arcgisscripting

gp = arcgisscripting.create()

gp.Overwriteoutput = 1



#Specify the location for the new shapefile.

gp.CreateFeatureclass("C:/temp/", "test_line.shp", "POLYLINE")



#Define Coordinate System

gp.workspace = "C:/temp/"

gp.toolbox = "management"

coordsys = "Coordinate Systems/Geographic Coordinate Systems/North America/North American Datum 1983.prj"

gp.defineprojection("test_line.shp", coordsys)



#Open a cursor to insert rows into the shapefile.

cur = gp.InsertCursor("C:/temp/test_line.shp")



#Create an Array and Point object.

lineArray = gp.CreateObject("Array")

pnt = gp.CreateObject("Point")



#Open a cursor on the table of XY coordinates to read from. 

rows = gp.SearchCursor("c:/pythonTest.dbf")



#Reset the cursor to the top.

row = rows.Next()



#Loop through each record in the XY table..



while row:



    #Set the X and Y coordinates for origin vertex.

    pnt.x = row.GetValue("Origin_x")

    pnt.y = row.GetValue("Origin_y")

    

    #Insert it into the line array    

    lineArray.add(pnt)

    

    #Set the X and Y coordinates for destination vertex

    pnt.x = row.GetValue("dest_x")

    pnt.y = row.GetValue("dest_y")



    #Insert it into the line array

    lineArray.add(pnt)

    

    #Go to next row in table.    

    row = rows.Next()



    #Insert the new poly into the feature class.

    feat = cur.NewRow()

    feat.shape = lineArray

    cur.InsertRow(feat)

    lineArray.RemoveAll()

    

del cur, row, rows

The formatting of the source table should include X and Y data for both the origin and destination points. -show me-
The script can be expanded to process the output feature class in various ways. A few examples are adding fields and calculate values, appending the new values to an existing feature class, or adding features to an existing topology.

The sample code is slightly different for versions of ArcGIS prior to version 9.2:

import sys, string, os, win32com.client

gp = win32com.client.Dispatch("esriGeoprocessing.GpDispatch.1")

gp.Overwriteoutput = 1



#Specify the location for the new shapefile.

gp.CreateFeatureclass("C:/temp/", "test_line.shp", "POLYLINE")



#Define Coordinate System

gp.workspace = "C:/temp/"

gp.toolbox = "management"

coordsys = "Coordinate Systems/Geographic Coordinate Systems/North America/North American Datum 1983.prj"

gp.defineprojection("test_line.shp", coordsys)



#Open a cursor to insert rows into the shapefile.

cur = gp.InsertCursor("C:/temp/test_line.shp")



#Create an Array and Point object.

lineArray = gp.CreateObject("Array")

pnt = gp.CreateObject("Point")



#Open a cursor on the table of XY coordinates to read from. 

rows = gp.SearchCursor("c:/pythonTest.dbf") 



#Reset the cursor to the top.

row = rows.Next()



#Loop through each record in the XY table..



while row:



    #Set the X and Y coordinates for origin vertex.

    pnt.x = row.GetValue("Origin_x")

    pnt.y = row.GetValue("Origin_y")

    

    #Insert it into the line array    

    lineArray.add(pnt)

    

    #Set the X and Y coordinates for destination vertex

    pnt.x = row.GetValue("dest_x")

    pnt.y = row.GetValue("dest_y")



    #Insert it into the line array

    lineArray.add(pnt)

    

    #Go to next row in table.    

    row = rows.Next()



    #Insert the new poly into the feature class.

    feat = cur.NewRow()

    feat.shape = lineArray

    cur.InsertRow(feat)

    lineArray.RemoveAll()

    

del cur, row, rows

Created: 9/27/2006
Last Modified: 11/25/2009