[pgrouting-users] Linestring query

[Patrick Higgins]

Many thanks Gavin, I will start there.
Patrick

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Sent: 27 November 2014 12:21
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Today's Topics:

   1. Linestring query (Patrick Higgins)
   2. Re: Linestring query (Gavin Fleming)


----------------------------------------------------------------------

Message: 1
Date: Thu, 27 Nov 2014 11:49:07 +0000
From: Patrick Higgins <PHiggins at pkc.gov.uk>
To: "'pgrouting-users at lists.osgeo.org'"
	<pgrouting-users at lists.osgeo.org>
Subject: [pgrouting-users] Linestring query
Message-ID:
	<37DE9C197285FD4C9D57A2B8C0647E6C0FDAA909 at PEREXC02.pkc.gov.uk>
Content-Type: text/plain; charset="us-ascii"

Hello

Could anyone please tell me if pgRouting has the facility to be able to place a point at a specified distance (e.g. 300m) along a linestring from a point of origin?

The problem summed up:  Which houses/properties are within a 300, or 600m walking distance from a play area, where the walking route follows the pavement/ sidewalk/ established path route, but not through private property?

In the past, a circle of 300/600m radius has been used, but this then includes properties which are in actual fact further than 300/600m walking distance.

The point of origin is a play park centroid.

The linestring could be a single linestring, such as a highway centre line, in which case there would be a single point at 300m along the linestring from the point of origin.

Alternatively, the linestring could be one which after 150m, meets another linestring, a junction heading west, in which case points would be placed on both the original linestring (at 300m) and on the westward one (at 150m + 150m).

It is envisaged that we will use this tool to generate walking distances from woodlands, ponds and so on.

Many thanks
Patrick Higgins

------------------------------

Message: 2
Date: Thu, 27 Nov 2014 14:20:54 +0200
From: Gavin Fleming <gavin at afrispatial.co.za>
To: pgRouting users mailing list <pgrouting-users at lists.osgeo.org>
Subject: Re: [pgrouting-users] Linestring query
Message-ID: <54771726.5070309 at afrispatial.co.za>
Content-Type: text/plain; charset="windows-1252"

Linear referencing sounds like a good approach for this problem:

http://postgis.net/docs/manual-2.1/reference.html#Linear_Referencing

On 27/11/2014 13:49, Patrick Higgins wrote:
>
> Hello
>
>  
>
> Could anyone please tell me if pgRouting has the facility to be able 
> to place a point at a specified distance (e.g. 300m) along a 
> linestring from a point of origin?
>
>  
>
> The problem summed up:*  Which houses/properties are within a 300, or 
> 600m walking distance from a play area, where the walking route 
> follows the pavement/ sidewalk/ established path route, but not 
> through private property?*
>
> * *
>
> *In the past, a circle of 300/600m radius has been used, but this then 
> includes properties which are in actual fact further than 300/600m 
> walking distance.*
>
>  
>
> The point of origin is a play park centroid.
>
>  
>
> The linestring could be a single linestring, such as a highway centre 
> line, in which case there would be a single point at 300m along the 
> linestring from the point of origin.
>
>  
>
> Alternatively, the linestring could be one which after 150m, meets 
> another linestring, a junction heading west, in which case points 
> would be placed on both the original linestring (at 300m) and on the 
> westward one (at 150m + 150m).
>
>  
>
> It is envisaged that we will use this tool to generate walking 
> distances from woodlands, ponds and so on.
>
>  
>
> Many thanks
>
> Patrick Higgins



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