[pgrouting-users] Pgrouting-users Digest, Vol 81, Issue 2

Omar_Fernando_Pessoa · June 24, 2015, 11:30am

You can find the nearest point using <#> operator. It’s faster.

SELECT source, target, id, ST_LineLocatePoint(the_geom, ST_GeometryFromText(‘POINT(%.4f %.4f)’,4326)) as percentual FROM vertex_ruas ORDER BY the_geom <#> ST_GeometryFromText(‘POINT(%.4f %.4f)’,4326) LIMIT 1;

···

2015-06-23 18:04 GMT-03:00 <pgrouting-users-request@lists.osgeo.org>:

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Today’s Topics:

Reg: Get nearest node in osm data (Manikanta Kondeti)

Re: Reg: Get nearest node in osm data (Stephen Woodbridge)

Re: Reg: Get nearest node in osm data (Manikanta Kondeti)

Message: 1
Date: Wed, 24 Jun 2015 01:26:32 +0530
From: Manikanta Kondeti <mani.iiit123@gmail.com>
To: pgRouting users mailing list <pgrouting-users@lists.osgeo.org>
Subject: [pgrouting-users] Reg: Get nearest node in osm data
Message-ID:
<CAMxCCEbigsduMLqQXQUsd=SzBi76F1ZZy1bcFhd9DG=WKvT_wg@mail.gmail.com>
Content-Type: text/plain; charset=“utf-8”

Hi,

I am writing a small application to get the route on the map. I am using
openlayers.js on client and pgrouting as a backend routing library for my
project. When a click is triggered I get a lat, lon, and I have the osm
data in postgres which is loaded using osm2pgrouting. I’ll pass this
lat,lon to server and I have to find the nearest node id from this
lat,lon. Can I query the database and get it done? Help me out.

Thank you,
Mani
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Message: 2
Date: Tue, 23 Jun 2015 16:25:53 -0400
From: Stephen Woodbridge <woodbri@swoodbridge.com>
To: pgrouting-users@lists.osgeo.org
Subject: Re: [pgrouting-users] Reg: Get nearest node in osm data
Message-ID: <5589C0D1.3080809@swoodbridge.com>
Content-Type: text/plain; charset=windows-1252; format=flowed

On 6/23/2015 3:56 PM, Manikanta Kondeti wrote:

Hi,

I am writing a small application to get the route on the map. I am
using openlayers.js on client and pgrouting as a backend routing library
for my project. When a click is triggered I get a lat, lon, and I have
the osm data in postgres which is loaded using osm2pgrouting. I’ll pass
this lat,lon to server and I have to find the nearest node id from this
lat,lon. Can I query the database and get it done? Help me out.

Probably you want to do this in two steps:

find the nearest edge

find the nearest node along the edge

Anyway your queries will be something like:

– get the closest edge
select * from edges where st_dwithin(geom, st_setsrid(st_makepoint(long,
lat), 4326), maxdist) order by st_distance(geom,
st_setsrid(st_makepoint(long, lat), 4326)) asc limit 1;

– get closest node along edge
select case when st_line_locate_point(geom,st_setsrid(st_makepoint(long,
lat), 4326)) < 0.5 then source else target from edges edge_id=id

– or search to just get the closest node
select * from nodes where st_dwithin(geom, st_setsrid(st_makepoint(long,
lat), 4326), maxdist) order by st_distance(geom,
st_setsrid(st_makepoint(long, lat), 4326)) asc limit 1;

where:

maxdist - maximum distance to search for geometries in db units probably
degrees

long, lat - values for the location in question

id - is the id of the closest edge found in the first query

Message: 3
Date: Wed, 24 Jun 2015 02:33:57 +0530
From: Manikanta Kondeti <mani.iiit123@gmail.com>
To: pgRouting users mailing list <pgrouting-users@lists.osgeo.org>
Subject: Re: [pgrouting-users] Reg: Get nearest node in osm data
Message-ID:
<CAMxCCEZpdrsYZh=QXHkZaU2gbAtBgC8jvoTLQm=V=O1jc6YwVA@mail.gmail.com>
Content-Type: text/plain; charset=“utf-8”

Hi Steve,

Thanks a lot for your response.

On Wed, Jun 24, 2015 at 1:55 AM, Stephen Woodbridge <woodbri@swoodbridge.com

wrote:

On 6/23/2015 3:56 PM, Manikanta Kondeti wrote:

Hi,

I am writing a small application to get the route on the map. I am
using openlayers.js on client and pgrouting as a backend routing library
for my project. When a click is triggered I get a lat, lon, and I have
the osm data in postgres which is loaded using osm2pgrouting. I’ll pass
this lat,lon to server and I have to find the nearest node id from this
lat,lon. Can I query the database and get it done? Help me out.

Probably you want to do this in two steps:

find the nearest edge

find the nearest node along the edge

Anyway your queries will be something like:

This is working perfect and found the nearest edge.

– get the closest edge
select * from edges where st_dwithin(geom, st_setsrid(st_makepoint(long,
lat), 4326), maxdist) order by st_distance(geom,
st_setsrid(st_makepoint(long, lat), 4326)) asc limit 1;

This is giving me syntax error. I’ve added the screenshot

– get closest node along edge
select case when st_line_locate_point(geom,st_setsrid(st_makepoint(long,
lat), 4326)) < 0.5 then source else target from edges edge_id=id

This is not giving me any nearest nodes. I’ve this screenshot as well.

– or search to just get the closest node
select * from nodes where st_dwithin(geom, st_setsrid(st_makepoint(long,
lat), 4326), maxdist) order by st_distance(geom,
st_setsrid(st_makepoint(long, lat), 4326)) asc limit 1;

where:

maxdist - maximum distance to search for geometries in db units probably
degrees

long, lat - values for the location in question

id - is the id of the closest edge found in the first query

Let me know if I miss something.

Thanks,
Mani

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End of Pgrouting-users Digest, Vol 81, Issue 2

…
Omar Fernando Pessôa
http://www.opessoa.com
Desenvolvedor de sistemas
Programador C# e C++