# Polyline (arcpy)

## Summary

A Polyline object is a shape defined by one or more paths, in which a path is a series of connected segments.

## Discussion

In many geoprocessing workflows, you may need to run a specific operation using coordinate and geometry information but don't necessarily want to go through the process of creating a new (temporary) feature class, populating the feature class with cursors, using the feature class, then deleting the temporary feature class. Geometry objects can be used instead for both input and output to make geoprocessing simpler. Geometry objects can be created from scratch using Geometry, Multipoint, PointGeometry, Polygon, or Polyline classes.

## Syntax

**Polyline (inputs, {spatial_reference}, {has_z}, {has_m})**

Parameter | Explanation | Data Type |

inputs |
The coordinates used to create the object. The datatype can be either Point or Array objects. | Object |

spatial_reference |
The spatial reference of the new geometry. (The default value is None) | SpatialReference |

has_z |
The Z state: True for geometry if Z is enabled and False if it is not. (The default value is False) | Boolean |

has_m |
The M state: True for geometry if M is enabled and False if it is not. (The default value is False) | Boolean |

## Properties

Property | Explanation | Data Type |

JSON (Read Only) | Returns a JSON representation of the geometry as a string. Tip: The returned string can be converted to a dictionary using Python's json.loads function. | String |

WKB (Read Only) | Returns the well-known binary (WKB) representation for OGC geometry. It provides a portable representation of a geometry value as a contiguous stream of bytes. | Bytearray |

WKT (Read Only) | Returns the well-known text (WKT) representation for OGC geometry. It provides a portable representation of a geometry value as a text string. | String |

area (Read Only) |
The area of a polygon feature. Empty for all other feature types. | Double |

centroid (Read Only) |
The true centroid if it is within or on the feature; otherwise, the label point is returned. Returns a point object. | Point |

extent (Read Only) |
The extent of the geometry. | Extent |

firstPoint (Read Only) |
The first coordinate point of the geometry. | Point |

hullRectangle (Read Only) |
A space-delimited string of the coordinate pairs of the convex hull rectangle. | String |

isMultipart (Read Only) |
True, if the number of parts for this geometry is more than one. | Boolean |

labelPoint (Read Only) |
The point at which the label is located. The labelPoint is always located within or on a feature. | Point |

lastPoint (Read Only) |
The last coordinate of the feature. | Point |

length (Read Only) |
The length of the linear feature. Zero for point and multipoint feature types. | Double |

length3D (Read and Write) | The 3D length of the linear feature. Zero for point and multipoint feature types. | Double |

partCount (Read Only) |
The number of geometry parts for the feature. | Integer |

pointCount (Read Only) |
The total number of points for the feature. | Integer |

spatialReference (Read Only) | The spatial reference of the geometry. | SpatialReference |

trueCentroid (Read Only) |
The center of gravity for a feature. | Point |

type (Read Only) |
The geometry type: polygon, polyline, point, multipoint, multipatch, dimension, or annotation. | String |

## Method Overview

Method | Explanation |

boundary () |
Constructs the boundary of the geometry. |

buffer (distance) |
Constructs a polygon at a specified distance from the geometry. |

clip (envelope) |
Constructs the intersection of the geometry and the specified extent. |

contains (second_geometry) |
Indicates if the base geometry contains the comparison geometry. contains is the opposite of within. Only True relationships are shown in this illustration. |

convexHull () |
Constructs the geometry that is the minimal bounding polygon such that all outer angles are convex. |

crosses (second_geometry) |
Indicates if the two geometries intersect in a geometry of a lesser shape type. Two polylines cross if they share only points in common, at least one of which is not an endpoint. A polyline and an polygon cross if they share a polyline or a point (for vertical line) in common on the interior of the polygon which is not equivalent to the entire polyline. Only True relationships are shown in this illustration. |

difference (other) |
Constructs the geometry that is composed only of the region unique to the base geometry but not part of the other geometry. The following illustration shows the results when the red polygon is the source geometry. |

disjoint (second_geometry) |
Indicates if the base and comparison geometries share no points in common. Two geometries intersect if disjoint returns False. Only True relationships are shown in this illustration. |

distanceTo (other) |
Returns the minimum distance between two geometries. If the geometries intersect, the minimum distance is 0. Both geometries must have the same projection. |

equals (second_geometry) |
Indicates if the base and comparison geometries are of the same shape type and define the same set of points in the plane. This is a 2D comparison only; M and Z values are ignored. Only True relationships are shown in this illustration. |

getArea (type) |
Returns the area of the feature using a measurement type. |

getLength (measurement_type) |
Returns the length of the feature using a measurement type. |

getPart ({index}) |
Returns an array of point objects for a particular part of geometry or an array containing a number of arrays, one for each part. |

intersect (other, dimension) |
Constructs a geometry that is the geometric intersection of the two input geometries. Different dimension values can be used to create different shape types. The intersection of two geometries of the same shape type is a geometry containing only the regions of overlap between the original geometries. For faster results, test if the two geometries are disjoint before calling intersect. |

overlaps (second_geometry) |
Indicates if the intersection of the two geometries has the same shape type as one of the input geometries and is not equivalent to either of the input geometries. Only True relationships are shown in this illustration. |

positionAlongLine (value, {use_percentage}) |
Returns a point on a line at a specified distance from the beginning of the line. |

projectAs (spatial_reference, {transformation_name}) |
Projects a geometry and optionally applies a geotransformation. To project, the geometry needs to have a spatial reference, and not have an UnknownCoordinateSystem. The new spatial reference system passed to the method defines the output coordinate system. If either spatial reference is unknown the coordinates will not be changed. The Z- and measure values are not changed by the ProjectAs method. |

symmetricDifference (other) |
Constructs the geometry that is the union of two geometries minus the instersection of those geometries. The two input geometries must be the same shape type. |

touches (second_geometry) |
Indicates if the boundaries of the geometries intersect. Two geometries touch when the intersection of the geometries is not empty, but the intersection of their interiors is empty. For example, a point touches a polyline only if the point is coincident with one of the polyline end points. Only True relationships are shown in this illustration. |

union (other) |
Constructs the geometry that is the set-theoretic union of the input geometries. The two geometries being unioned must be the same shape type. |

within (second_geometry) |
Indicates if the base geometry is within the comparison geometry. within is the opposite operator of contains. Only True relationships are shown in this illustration. |

## Methods

**boundary ()**

Data Type | Explanation |

Object |
A polygon's boundary is a polyline. A polyline's boundary is a multipoint, corresponding to the endpoints of the line. A point or multipoint's boundary is an empty point or multipoint. |

**buffer (distance)**

Parameter | Explanation | Data Type |

distance |
The buffer distance. The buffer distance is in the same units as the geometry that is being buffered. A negative distance can only be specified against a polygon geometry. | Double |

Data Type | Explanation |

Polygon |
The buffered polygon geometry. |

**clip (envelope)**

Parameter | Explanation | Data Type |

envelope |
An extent object used to define the clip extent. | Extent |

Data Type | Explanation |

Object |
An output geometry clipped to the specified extent. |

**contains (second_geometry)**

Parameter | Explanation | Data Type |

second_geometry |
A second geometry. | Object |

Data Type | Explanation |

Boolean |
A return Boolean value of True indicates this geometry contains the second geometry. |

**convexHull ()**

Data Type | Explanation |

Object |
The resulting geometry. The convex hull of a single point is the point itself. |

**crosses (second_geometry)**

Parameter | Explanation | Data Type |

second_geometry |
A second geometry. | Object |

Data Type | Explanation |

Boolean | A return Boolean value of True indicates the two geometries intersect in a geometry of a lesser shape type. |

**difference (other)**

Parameter | Explanation | Data Type |

other |
A second geometry. | Object |

Data Type | Explanation |

Object |
The resulting geometry. |

**disjoint (second_geometry)**

Parameter | Explanation | Data Type |

second_geometry |
A second geometry. | Object |

Data Type | Explanation |

Boolean | A return Boolean value of True indicates that the two geometries share no points in common. |

**distanceTo (other)**

Parameter | Explanation | Data Type |

other |
A second geometry. | Object |

Data Type | Explanation |

Double |
The distance between the two geometries. |

**equals (second_geometry)**

Parameter | Explanation | Data Type |

second_geometry |
A second geometry. | Object |

Data Type | Explanation |

Boolean |
A return Boolean value of True indicates that the two geometries are of the same shape type and define the same set of points in the plane. |

**getArea (type)**

Parameter | Explanation | Data Type |

type | PLANAR measurements reflect the projection of geographic data onto the 2D surface (in other words, they will not take into account the curvature of the earth). GEODESIC, GREAT_ELLIPTIC, LOXODROME, and PRESERVE_SHAPE measurement types may be chosen as an alternative, if desired. - GEODESIC —The shortest line between any two points on the earth's surface on a spheroid (ellipsoid). One use for a geodesic line is when you want to determine the shortest distance between two cities for an airplane's flight path. This is also known as a great circle line if based on a sphere rather than an ellipsoid.
- GREAT_ELLIPTIC —The line on a spheroid (ellipsoid) defined by the intersection at the surface by a plane that passes through the center of the spheroid and the start and endpoints of a segment. This is also known as a great circle when a sphere is used.
- LOXODROME —A loxodrome is not the shortest distance between two points but instead defines the line of constant bearing, or azimuth. Great circle routes are often broken into a series of loxodromes, which simplifies navigation. This is also known as a rhumb line.
- PLANAR —Planar measurement use 2D Cartesian mathematics to calculate lengths and areas. This option is only available when measuring in a projected coordinate system and the 2D plane of that coordinate system will be used as the basis for the measurements.
- PRESERVE_SHAPE —This type calculates the area or length of the geometry on the surface of the Earth ellipsoid, for geometry defined in a projected or geographic coordinate system. This option preserves the shape of the geometry in its coordinate system.
| String |

Data Type | Explanation |

Double |
The area of the feature. Areas are always returned in square meters. |

**getLength (measurement_type)**

Parameter | Explanation | Data Type |

measurement_type |
PLANAR measurements reflect the projection of geographic data onto the 2D surface (in other words, they will not take into account the curvature of the earth). GEODESIC, GREAT_ELLIPTIC, LOXODROME, and PRESERVE_SHAPE measurement types may be chosen as an alternative, if desired. - GEODESIC —The shortest line between any two points on the earth's surface on a spheroid (ellipsoid). One use for a geodesic line is when you want to determine the shortest distance between two cities for an airplane's flight path. This is also known as a great circle line if based on a sphere rather than an ellipsoid.
- GREAT_ELLIPTIC —The line on a spheroid (ellipsoid) defined by the intersection at the surface by a plane that passes through the center of the spheroid and the start and endpoints of a segment. This is also known as a great circle when a sphere is used.
- LOXODROME —A loxodrome is not the shortest distance between two points but instead defines the line of constant bearing, or azimuth. Great circle routes are often broken into a series of loxodromes, which simplifies navigation. This is also known as a rhumb line.
- PLANAR —Planar measurement use 2D Cartesian mathematics to calculate lengths and areas. This option is only available when measuring in a projected coordinate system and the 2D plane of that coordinate system will be used as the basis for the measurements.
- PRESERVE_SHAPE —This type calculates the area or length of the geometry on the surface of the Earth ellipsoid, for geometry defined in a projected or geographic coordinate system. This option preserves the shape of the geometry in its coordinate system.
| String |

Data Type | Explanation |

Double |
The length of the linear feature. Lengths are always returned in meters. |

**getPart ({index})**

Parameter | Explanation | Data Type |

index |
The index position of the geometry. | Integer |

Data Type | Explanation |

Array |
getPart returns an array of point objects for a particular part of the geometry if an index is specified. If an index is not specified, an array containing an array of point objects for each geometry part is returned. |

**intersect (other, dimension)**

Parameter | Explanation | Data Type |

other |
The second geometry. | Object |

dimension | The topological dimension (shape type) of the resulting geometry. - 1 —A zero-dimensional geometry (point or multipoint).
- 2 —A one-dimensional geometry (polyline).
- 4 —A two-dimensional geometry (polygon).
| Integer |

Data Type | Explanation |

Object |
A new geometry (point, multipoint, polyline, or polygon) that is the geometric intersection of the two input geometries. |

**overlaps (second_geometry)**

Parameter | Explanation | Data Type |

second_geometry |
A second geometry. | Object |

Data Type | Explanation |

Boolean | A return Boolean value of True indicates the intersection of the two geometries has the same dimension as one of the input geometries. |

**positionAlongLine (value, {use_percentage})**

Parameter | Explanation | Data Type |

value |
The distance along the line. If the distance is less than zero, then the starting point of the line will be returned; if the distance is greater than the length of the line, then the end point of the line will be returned. | Double |

use_percentage | The distance may be specified as a fixed unit of measure or a ratio of the length of the line. If True, value is used as a percentage; if False, value is used as a distance. (The default value is False) | Boolean |

Data Type | Explanation |

PointGeometry |
The point on the line at a specified distance from the beginning of the line. |

**projectAs (spatial_reference, {transformation_name})**

Parameter | Explanation | Data Type |

spatial_reference |
The new spatial reference. This can be a SpatialReference object or the coordinate system name. | SpatialReference |

transformation_name | The geotransformation name. | String |

Data Type | Explanation |

Object |
The projected geometry. |

**symmetricDifference (other)**

Parameter | Explanation | Data Type |

other |
A second geometry. | Object |

Data Type | Explanation |

Object |
The resulting geometry. |

**touches (second_geometry)**

Parameter | Explanation | Data Type |

second_geometry |
A second geometry. | Object |

Data Type | Explanation |

Boolean | A return Boolean value of True indicates the boundaries of the geometries intersect. |

**union (other)**

Parameter | Explanation | Data Type |

other |
A second geometry. | Object |

Data Type | Explanation |

Object |
The resulting geometry. |

**within (second_geometry)**

Parameter | Explanation | Data Type |

second_geometry |
A second geometry. | Object |

Data Type | Explanation |

Boolean | A return Boolean value of True indicates this geometry is contained within the second geometry. |

## Code Sample

Create a polyline feature class from scratch.

```
import arcpy
# A list of features and coordinate pairs
feature_info = [[[1, 2], [2, 4], [3, 7]],
[[6, 8], [5, 7], [7, 2], [9, 5]]]
# A list that will hold each of the Polyline objects
features = []
for feature in feature_info:
# Create a Polyline object based on the array of points
# Append to the list of Polyline objects
features.append(
arcpy.Polyline(
arcpy.Array([arcpy.Point(*coords) for coords in feature])))
# Persist a copy of the Polyline objects using CopyFeatures
arcpy.CopyFeatures_management(features, "c:/geometry/polylines.shp")
```