## Question

**gsiewruk** on *Sat, 31 May 2014 12:36:02 *

I have a table which contain information about edges of the graph in form of ```
geometry
linestring
```

. Spatial result of query ```
select
* from edge
```

look like this

**EACH** `linestring`

is
created always from two ```
geometry
points
```

with insert statement like:

`INSERT INTO edge VALUES( geometry::Parse('LINESTRING(1 1 ,1 2)'))`

In order to finding shortest path between two points I have implemented `Dijkstra`

algorith
according toDijkstra in c#, However I have found out about STDistance() function
which is ment to do the same thing just by executing simple query. Could anyone give me a hint how could I use `STDistance`

with
objects created like I described? Every example I find use `linestrings`

created
from 3 points.

I have difficulty using example in the situation I have lets say 3 `linestrings`

as
bellow:

```
INSERT INTO edge VALUES( geometry::Parse('LINESTRING(1 1 ,1 2)'))
INSERT INTO edge VALUES( geometry::Parse('LINESTRING(1 2 ,1 3)'))
INSERT INTO edge VALUES( geometry::Parse('LINESTRING(1 3 ,1 4)'))
```

and finding shortest path from ```
1
1
```

to ```
1
4
```

**Edit:** I have suceeded with combining all linestrings into one shape by:

`SELECT geometry::UnionAggregate(linestring) FROM edge`

i get shape :

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

Now I use `STDistance`

as
follows:

`SELECT (geometry::UnionAggregate(linestring)).STDistance(geometry::STGeomFromText('POINT(0 0)', 0)) FROM edge`

However the return value is about distance between point (0,0) and presented shape, when my intend is to count edges length from one point to the other, any clues?

## Replies

**gsiewruk** on *Sat, 31 May 2014 14:50:08 *

edited question

**tracycai** on *Mon, 02 Jun 2014 03:23:14 *

Hi,

To calculate the distance between two points, use the query like:

DECLARE @g geometry; DECLARE @h geometry; SET @g = geometry::STGeomFromText('POINT(1 1)', 0); SET @h = geometry::STGeomFromText('POINT(1 2)', 0); SELECT @g.STDistance(@h);

STDistance (geometry Data Type)

http://msdn.microsoft.com/en-us/LIBRARY/bb933952

Thanks.