[OpenLayers-Users] custom getFeatureInfo control / problem with layer pixels

[Mario Nuñez Jimenez]

Hello Gery,
I am just trying to do my own getFeatureInfo control by capturing the click on map event.

The problem is to fit the x and y pixels from the click event on the x and y needed to do a getfeatureinfo request  to my wms.

The idea is that the X and Y from the event are taken from the viewport/base layer (the complete picture shown in the map) but I need to do a get feature info request about other layer loaded in the map, a smaller map shown over the base layer (it only occupies a small area).

Every time I want to use the X and Y that I get from the event I have a result from my getfeatureinfo request even If I clicked out that layer area, so it's a nonsense since it should replied with some kind of "you are out of the layer extension so there is no data were you clicked".  Also if I cliked in a subarea of my layer the result of the getfeatureinfo request says "you clicked in area Z" but I didn't clicked in subarea Z, so I think the X and Y should be related to the layer you are querying  but I don't know how to do that.

Cheers,
Mario.

-----Original Message-----
From: Gery . [mailto:gamejihou at hotmail.com] 
Sent: jueves, 14 de febrero de 2013 20:45
To: Mario Nuñez Jimenez
Cc: openlayers-users at lists.osgeo.org
Subject: Re: [OpenLayers-Users] custom getFeatureInfo control / problem with layer pixels

I've recently tested the openlayers.control.getfeature to do something related to your question but sorry to say this, I didn't understand what you're trying to do.

Sent from my iBath

On Feb 14, 2013, at 19:12, "negroscuro" <mario.nunez at atosresearch.eu> wrote:

Hello,
I am trying to do a customized getFeatureInfo, so in order to do the request to the WMS I need to know the I and J defined in the OGC WMS 1.3.0 specification, I mean to do the getFeatureInfo request i need a I and J, being those I and J pixels of the layer.

If I am not wrong, when I implemented a control to handle the click on map event, I get a X and Y pixels but those pixels I guess that dont match the layers ones because that x and y from the event are based in the viewport extension and not in a concrete layer extension so my question here is how to get the choosen layer X and Y when I click on it or just get some null value to know that I am clicking outside my concrete layer.

I know which layer is selected but I dont know how to convert the vieport x and y clicked in that layer's X and Y pixels.

Do I explained myself clearly enough?
Sorry for my english.
Thank you in advance for helping
Cheers.



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