All,

It's probably not the cleanest way to approach it, but maybe a straight 
imagemap type approach.   You use the four corners of the label bounding poly 
and send as an imagemap or json set or id query.

I think the bounding polys need to somehow be thought of as a ad-hoc data layer 
themselves.  Is there a way of sub-selecting feature constructs (that were 
originated by mapserver, like centroids are, into a reusable (on the fly) 
dataset?

My immediate thoughts were to use a clientside imagemage (which is passe these 
days) and that is where the translation occurs for the bounding boxes, via the 
imagemap generation.

bobb
________________________________________
From: Lime, Steve D (MNIT)
Sent: Monday, January 20, 2014 9:43 AM
To: Basques, Bob (CI-StPaul); wiltomap; mapserver-users@lists.osgeo.org
Subject: RE: [mapserver-users] Clickable label

That or a UTFGrid. I don't believe that support (in master) handles labels but 
maybe it could. In UTFGrid context you wouldn't want to render characters 
anyway, only the bounding polygons. However, because the grid is rendered at a 
lower resolution than the related map label placement consistency might be the 
issue. --Steve
________________________________________
From: Basques, Bob (CI-StPaul)
Sent: Friday, January 10, 2014 6:15 PM
To: Lime, Steve D (MNIT); wiltomap; mapserver-users@lists.osgeo.org
Subject: RE: [mapserver-users] Clickable label

Steve,

I've been thinking on this thread since it started, I wonder, could you use a 
imagemap template from Mapserver, but populate it with the Label bounding 
polygons?

bobb


________________________________________
From: mapserver-users-boun...@lists.osgeo.org 
[mapserver-users-boun...@lists.osgeo.org] on behalf of Lime, Steve D (MNIT) 
[steve.l...@state.mn.us]
Sent: Friday, January 10, 2014 4:14 PM
To: wiltomap; mapserver-users@lists.osgeo.org
Subject: Re: [mapserver-users] Clickable label

 This can't be done with stock MapServer. Labels are dynamic by nature and are 
the product of a map raw while queries work off the base data. The bridge 
between the map and a query is a conversion from pixels to map coordinates 
based on map size and extent.

You might be able to pull this off using MapScript. For a query you'd have to 
do things in two stages:

  1) Draw the map (in memory) based on the map the user interacted with (same 
extent, size and set of layers) so that a label cache is created.
  2) Search the label cache based on the query point and based on that pull the 
appropriate feature.

I don't know if step 2 is feasible or not. You used to be able to loop through 
it, not sure about now.

There might be other ways using an image where you render text and label 
backgrounds using the same color, a color that you could map back to a feature 
id. The map would basically contain label polygons in a raster you could, in 
turn, query that raster using point and retrieve a feature id. I have doubts 
that you could match the first image to the second so this would be a huge long 
shot.

Steve

-----Original Message-----
From: mapserver-users-boun...@lists.osgeo.org 
[mailto:mapserver-users-boun...@lists.osgeo.org] On Behalf Of wiltomap
Sent: Friday, January 10, 2014 2:17 AM
To: mapserver-users@lists.osgeo.org
Subject: [mapserver-users] Clickable label

Hello all,

I have to display labels instead of points on a layer. The labels rely on an 
attribute value. I would like to click on the label to make an attribute 
windows open up. So far, no problem with mapfile configuration...

The only thing is that the attribute window opens up when I click right in the 
middle of the label. I can use TOLERANCEUNITS and TOLERANCE parameters in the 
mapfile to enlarge the clickable area BUT this means that I can also click next 
to the label and get the attribute window, which I don't want to...

My purpose is to get the attribute window whereever I click on the label (any 
part of it) and not if I click next to it. Would you think about a solution to 
that ?

I enclose a scrennshot of the mapfile I have worked out so far.


Many thanks in advance,

Thomas


<http://osgeo-org.1560.x6.nabble.com/file/n5097281/mapfile_label.jpg>



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