ArcPy – How to Create Line from Two Points in Different Feature Classes

arcgis-10.1arcpymodelbuilder

I'm attempting to automate this in ModelBuilder in ArcMap. I have one feature class with one point (Start) and one feature class with multiple points (Destinations). I want to iterate through the Destinations so I create multiple lines from the Start point to each Destination point.

I was looking at possibly extracting the XY coordinates and then using "XY To Line", but that wants the xy to be in one table (or feature), not two. Is there a simpler way of connecting two points?

Best Answer

I don't have Arc on this machine but this should work. It would actually work with multiple start points, but will work on a single start point as well.

import arcpy

start_feature = arcpy.GetParameterAsText(0)
end_feature = arcpy.GetParameterAsText(1)
out_feature = arcpy.GetParameterAsText(2)

start_cursor = arcpy.SearchCursor(start_feature)
end_cursor = arcpy.SearchCursor(end_feature)

desc = arcpy.Describe(start_feature)
shapefieldname = desc.ShapeFieldName

point = arcpy.Point()
array = arcpy.Array()
featureList = []

cursor = arcpy.InsertCursor(out_feature)
feat = cursor.newRow()

for start in start_cursor:
    startFeature = start.getValue(shapefieldname)
    pnt1 = startFeature.getPart()
    for end in end_cursor:
        endFeature = end.getValue(shapefieldname)
        pnt2 = endFeature.getPart()
        point.X = pnt1.X
        point.Y = pnt1.Y
        array.add(point)
        point.X = pnt2.X
        point.Y = pnt2.Y
        array.add(point)
        polyline = arcpy.Polyline(array)
        array.removeAll()
        featureList.append(polyline)
        feat.shape = polyline
        cursor.insertRow(feat)

del feat, cursor, end_cursor, start_cursor

You may actually want to change the inputs so it creates the output file during the script instead of having to point at one that's already created, but that depends on what you want to do.

Related Solutions

[GIS] How to create points in a Feature Class from a database table

I am not sure whether nested cursors (e.g. a SearchCursor for the source table and an InsertCursor for the destination feature class) will work, but it's worth a shot.

Specific to your problem of how to get geometry data into a feature class using an InsertCursor:

Use a da.InsertCursor (since you have access to 10.1+)
Take a look at the Help page for arcpy.da.InsertCursor, particularly the examples. I think that you are making it more complex than necessary.

This is their example. No geometry objects needed, just the numeric values.

import arcpy

# A list of values that will be used to construct new rows
row_values = [('Anderson', (1409934.4442000017, 1076766.8192000017)),
              ('Andrews', (752000.2489000037, 1128929.8114))]

# Open an InsertCursor
cursor = arcpy.da.InsertCursor("C:/data/texas.gdb/counties", ("NAME", "SHAPE@XY"))

# Insert new rows that include the county name and a x,y coordinate
#  pair that represents the county center
for row in row_values:
    cursor.insertRow(row)

[GIS] How to batch merge point, polygon and line feature classes into a new feature class

I suggest populating a python dictionary. The key would be your category, and the values would be a python list of your feature classes to merge. Use a for loop to iterate through your geodatabases, and another to iterate through your feature classes. Check each feature class to determine if it contains points. If not, perform a Feature To Point conversion. Something like this (untested):

#-Locals

#List of GDBs
gdbs = [r"c:\test\NoxiousWeeds_points.gdb",
        r"c:\test\NoxiousWeeds_poly.gdb",
        r"c:\test\NoxiousWeeds_lines.gdb"]

#Merge GDB
mergeGdb = r"c:\test\NoxiousWeeds_merged.gdb"

#Workspace
#Use "in_memory" or workspace geodatabase on disk
workspace = "in_memory"

#-End Locals

#Import modules
from arcpy import *
import os

#dictionary to be populated with list of all feature classes
fcsDi = {}

#Garbage for deleting created feature classes
garbage = []

#Iterate through three GDBs
for gdb in gdbs:
    print "Iterating", gdb
    #Set workspace to GDB
    env.workspace = gdb

    #List feature classes in gdb
    fcs = ListFeatureClasses ()

    #Iterate through feature classes
    for fc in fcs:
        #Check if feature class is points
        shape = Describe (fc).shapeType
        if shape != "Point":
            #Feature to point
            outFile = os.path.join (workspace, fc + "_point")
            FeatureToPoint_management (fc, outFile, "INSIDE")
            garbage += [outFile]
        else:
            outFile = os.path.join (gdb, fc)

        #Remove unwanted text to determine merge
        fcCategory = fc.replace ("_poly", "").replace ("_lines", "").replace ("_points", "")

        #Check if category is in dictionary
        if fcCategory in fcsDi:
            fcsDi [fcCategory] += [outFile]
        #If not in dictionary
        else:
            fcsDi [fcCategory] = [outFile]

#Iterate through dictionary keys
for category in fcsDi:
    print "Merging", category
    #Path to merge feature class
    outFc = os.path.join (mergeGdb, category + "_merged")
    #Get list of feature classes from dictionary
    fcs = fcsDi [category]
    #Merge
    print "Created:", outFc
    Merge_management (fcs, outFc)

#Clean up
for trash in garbage:
    Delete_management (trash)

Best Answer

Related Solutions

[GIS] How to create points in a Feature Class from a database table

[GIS] How to batch merge point, polygon and line feature classes into a new feature class

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