(Since I'm not certain that this got through I'm resending. If it did,
please forgive me)
Hi all,
I need help with an unusual query (at least for me :] )
The objective is to find road segments with a type defined to tunnel
within a given distance.
This is needed because of gps signal spikes (speed-wise) at tunnel
exits...
Now given the following scenario of road segments:
=====*-----------------*==========
====V===*========================*
*======
=====*-----------------*==========
|
|
|
|
|
|
|
|
|
|
==========-----------------------=======================
= | road
- tunnel
* nodes
V vehicle
Now when I execute a distance-based query (for road segments of tunnel
type) I get the lower tunnel, which is closer.
But I want the upper one which is actually the one on the top.
the actual query is as follows (tunnels (road type=67) within a 150
metres radius) -- the road map is in WGS84:
SELECT name, road_type FROM $road_net WHERE
transform(geometry,$srid) &&
setsrid(expand(transform(geomfromtext('POINT($lon $lat)',4326),
$srid),150),$srid)
AND distance(transform(geomfromtext('POINT($lon $lat)',4326),$srid),
transform(geometry,$srid)) <=150 AND road_type=67;
Already thankful for any tips,
--
Pedro Doria Meunier <[EMAIL PROTECTED]>
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