On 8/15/2011 7:02 PM, Robert Sanson wrote:
What happens when your click point for a start or end is not directly on
a node? Does pgrouting snap the start/end points to the nearest vertex
on the nearest road?
I take the start and end points and in PHP connect to the database and
snap it to the nearest edge like this:
$sql = "SELECT gid, source, target, the_geom,
distance(the_geom, setsrid(makepoint(".
$lonlat[0].",".$lonlat[1]."), 4326)) AS dist
FROM ".TABLE."
WHERE the_geom && expand(setsrid(makepoint(".
$lonlat[0].",".$lonlat[1]."),4326), ".$EXPAND.")
ORDER BY dist LIMIT 1";
You can write some simple functions in plpgsql like:
find_nearest_link_within_distance()
find_nearest_node_within_distance()
find_node_by_nearest_link_within_distance()
I have these on one database, but I can remember if I wrote these or
they are part of pgRouting as I try to encapsulate most code in simple
function calls so it is reusable.
-Steve
Thanks,
Robert
>>> Stephen Woodbridge <[email protected]> 16/08/2011 6:43 a.m. >>>
On 8/15/2011 1:57 PM, sushma wrote:
> Hi Guys,
>
> I want to implement pgrouting using openlayers .i.e to find shortest path
> from building to another buildings.So if user clicks one building as
a start
> point and another as end point then it returns the shortest path between
> those buildings. I am totally new to the openlayers.
> So far i can display the map of road data and buildings from
geoserver using
> openlayers. Now i wanted to get on with click control. So need some
> suggestion how can i get on with click control.
Here is an example that I put together using mapserver for the maps,
pgRouting and I use a small PHP program to handle the the Ajax requests
to communicate between OpenLayers and pgRouting.
http://tinyurl.com/3vnufmh
-Steve
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