Getting all the points of polyline

Question

I have some polyline feature objects in Python. Now I want to get all the points of polylines.

For example, if a polyline has start point [0,0] end point [5,5]. Result: [1,1];[2,2];[3,3];[4,4];[5,5].

I want to find all the integer points on that line including end points. For straight line this is dead simple, but if polyline has Beizer Curve, Circular Arc, Elliptic Arc geometry types, then how can I do it?

I can only use those tools which are available in all license levels of ArcGIS. For example, ArcGIS Basic.

Answer 1

I know this is old but I was looking for the same as I don't have ArcInfo for the FeatureVerticesToPoints tools. After using Search cursor solution above I went forward to simplify the code and found that using NumPy Arrays in the Data Access Module a simple and very quick script could be produced. I'm using this as a script tool.

Note: The key is the explode_to_points parameter in arcpy.da.FeatureClassToNumPyArray

Here is link to ArcGIS Repository Location: Feature Class to Points

# Feature Class to Points
# 
# Paul Smith (2012) [email protected]

# Imports
import arcpy
import numpy

#Inputs from user parameters
InFc  = arcpy.GetParameterAsText(0) # input feature class
OutFc = arcpy.GetParameterAsText(1) # output feature class

# Spatial reference of input feature class
SR = arcpy.Describe(InFc).spatialReference

# Create NumPy array from input feature class
array = arcpy.da.FeatureClassToNumPyArray(InFc,["SHAPE@XY"], spatial_reference=SR, explode_to_points=True)

# Check array and Exit if no features found
if array.size == 0:
    arcpy.AddError(InFc + " has no features.")

# Create a new points feature class
else:
    arcpy.da.NumPyArrayToFeatureClass(array, OutFc, ['SHAPE@XY'], SR)

Answer 2

The following should work on polylines and polygons:

import arcpy

infc = r"D:\Projects\GDBs\slowbutter.gdb\fc"

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

rows = arcpy.SearchCursor(infc)
for row in rows:
    # Create the geometry object
    feat = row.getValue(shapefieldname)
    print "Feature %i: " % row.getValue(desc.OIDFieldName)
    partnum = 0
    # Step through each part of the feature
    for part in feat:
        print "Part %i: " % partnum
        part_list = []
        for pnt in feat.getPart(partnum):
            if pnt:
                # Add to list
                part_list.append([pnt.X, pnt.Y])
            else:
                # If pnt is None, this represents an interior ring
                print "Interior Ring:"
        partnum += 1  
        print part_list

For some UK road data, I get this; a nested list of X,Y pairs for each vertex that makes up the polyline:

Feature 7: 
Part 0: 
[[-0.48053999999996222, 51.482510000000048], [-0.48032999999992398, 
51.482609000000082], [-0.48026999999996178, 51.48273800000004], 
[-0.48043999999993048, 51.482891000000052], [-0.48065999999994347, 51.482948000000079],
[-0.48123999999995704, 51.483009000000038]]

Answer 3

As I understood you need to increase number of vertices for your polyline features. And also to transform all "Beizer Curve, Circular Arc, Elliptic Arc" segments into several line segments.

For this task in ArcGIS you can use Densify (Editing) tool in ArcToolbox.

Then you can convert your polylines' vertices to point features as suggested Darren Cope and artwork21.

If you prefer to do it in ArcMap take a look at Creating new points along a line help topic.

Answer 4

As Darren Cope has suggested, converting your layer to a point vertices may be done using the Feature Vertices to Points tool.

Here is the python code snippedt:

# import system modules 
import arcpy
from arcpy import env

# Set environment settings
env.workspace = "C:/data"

# Set local variables
inFeatures = "majorrds.shp"
outFeatureClass = "c:/output/output.gdb/majorrds_midpt"

# Execute FeatureVerticesToPoints
arcpy.FeatureVerticesToPoints_management(inFeatures, outFeatureClass, "MID")