---
title: "MultiLineString | Microsoft Docs"
ms.date: "06/14/2017"
ms.prod: "sql-server-2014"
ms.reviewer: ""
ms.technology: 
ms.topic: conceptual
helpviewer_keywords: 
  - "MultiLineString geometry subtype [SQL Server]"
  - "geometry subtypes [SQL Server]"
ms.assetid: 95deeefe-d6c5-4a11-b347-379e4486e7b7
author: MladjoA
ms.author: mlandzic
manager: craigg
---
# MultiLineString
  A `MultiLineString` is a collection of zero or more `geometry` or **geographyLineString** instances.  
  
## MultiLineString instances  
 The illustration below shows examples of `MultiLineString` instances.  
  
 ![Examples of geometry MultiLineString instances](../../database-engine/media/multilinestring.gif "Examples of geometry MultiLineString instances")  
  
 As shown in the illustration:  
  
-   Figure 1 is a simple `MultiLineString` instance whose boundary is the four endpoints of its two `LineString` elements.  
  
-   Figure 2 is a simple `MultiLineString` instance because only the endpoints of the `LineString` elements intersect. The boundary is the two non-overlapping endpoints.  
  
-   Figure 3 is a nonsimple `MultiLineString` instance because the interior of one of its `LineString` elements is intersected. The boundary of this `MultiLineString` instance is the four endpoints.  
  
-   Figure 4 is a nonsimple, nonclosed `MultiLineString` instance.  
  
-   Figure 5 is a simple, nonclosed `MultiLineString`. It is not closed because its `LineStrings` elements are not closed. It is simple because none of the interiors of any of the `LineStrings` instances intersect.  
  
-   Figure 6 is a simple, closed `MultiLineString` instance. It is closed because all its elements are closed. It is simple because none of its elements intersect at the interiors.  
  
### Accepted instances  
 For a `MultiLineString` instance to be accepted it must either be empty or comprised of only `LineString` intances that are accepted. For more information on accepted `LineString` instances, see [LineString](../spatial/linestring.md). The following are examples of accepted `MultiLineString` instances.  
  
```  
DECLARE @g1 geometry = 'MULTILINESTRING EMPTY';  
DECLARE @g2 geometry = 'MULTILINESTRING((1 1, 3 5), (-5 3, -8 -2))';  
DECLARE @g3 geometry = 'MULTILINESTRING((1 1, 5 5), (1 3, 3 1))';  
DECLARE @g4 geometry = 'MULTILINESTRING((1 1, 3 3, 5 5),(3 3, 5 5, 7 7))';  
```  
  
 The following example throws a `System.FormatException` because the second `LineString` instance is not valid.  
  
```  
DECLARE @g geometry = 'MULTILINESTRING((1 1, 3 5),(-5 3))';  
```  
  
### Valid instances  
 For a `MultiLineString` instance to be valid it must meet the following criteria:  
  
1.  All instances comprising the `MultiLineString` instance must be valid `LineString` instances.  
  
2.  No two `LineString` instances comprising the `MultiLineString` instance may overlap over an interval. The `LineString` instances can only intersect or touch themselves or other `LineString` instances at a finite number of points.  
  
 The following example shows three valid `MultiLineString` instances and one `MultiLineString` instance that is not valid.  
  
```  
DECLARE @g1 geometry = 'MULTILINESTRING EMPTY';  
DECLARE @g2 geometry = 'MULTILINESTRING((1 1, 3 5), (-5 3, -8 -2))';  
DECLARE @g3 geometry = 'MULTILINESTRING((1 1, 5 5), (1 3, 3 1))';  
DECLARE @g4 geometry = 'MULTILINESTRING((1 1, 3 3, 5 5),(3 3, 5 5, 7 7))';  
SELECT @g1.STIsValid(), @g2.STIsValid(), @g3.STIsValid(), @g4.STIsValid();  
```  
  
 `@g4` is not valid because the second `LineString` instance overlaps the first `LineString` instance at an interval. They touch at an infinite number of points.  
  
## Examples  
 The following example creates a simple `geometry``MultiLineString` instance containing two `LineString` elements with the SRID 0.  
  
```  
DECLARE @g geometry;  
SET @g = geometry::Parse('MULTILINESTRING((0 2, 1 1), (1 0, 1 1))');  
```  
  
 To instantiate this instance with a different SRID, use `STGeomFromText()` or `STMLineStringFromText()`. You can also use `Parse()` and then modify the SRID, as shown in the following example.  
  
```  
DECLARE @g geometry;  
SET @g = geometry::Parse('MULTILINESTRING((0 2, 1 1), (1 0, 1 1))');  
SET @g.STSrid = 13;  
```  
  
## See Also  
 [STLength (geometry Data Type)](/sql/t-sql/spatial-geometry/stlength-geometry-data-type)   
 [STIsClosed (geometry Data Type)](/sql/t-sql/spatial-geometry/stisclosed-geometry-data-type)   
 [LineString](../spatial/linestring.md)   
 [Spatial Data (SQL Server)](../spatial/spatial-data-sql-server.md)