[mapserver-dev] MapServer legend functionality

[Yewondwossen Assefa]

On 11/06/2010 12:13 PM, Kralidis,Tom [Ontario] wrote:
> Assefa: isn't this a GetMap request which outputs a legend image
> instead?  I see similar logic.
>
> I've seen CubeWerx use 'GetLegend', which displays a full legend, as a
> VendorSpecificParameter in their WMS implementation, which I think is
> very useful.
>
> ..Tom
>
>
>    
Correct, parameters to be able to use this functionality through OGC 
would be similar to a GetMap request. I like the idea of having the 
GetLegend interface. The other possiblity would have been to access it 
through a GetLegendGraphic with vendor specific parameters to 
accommodate this.
I was not aware of the CubeWerx GetLegend support. I also  think that It 
can be useful. I am not sure though that Cuberx has the concept of 
"visible elements only" in the legend support.

regards,


>> -----Original Message-----
>> From: mapserver-dev-bounces at lists.osgeo.org
>> [mailto:mapserver-dev-bounces at lists.osgeo.org] On Behalf Of
>> Yewondwossen Assefa
>> Sent: Friday, 11 June 2010 12:10
>> To: Lime, Steve D (DNR)
>> Cc: 'MapServer Dev Mailing List'
>> Subject: Re: [mapserver-dev] MapServer legend functionality
>>
>> On 11/06/2010 11:54 AM, Lime, Steve D (DNR) wrote:
>>      
>>> I think it would be a reasonable addition. Are you thinking about
>>> simply adding a visibility flag to a layer and flipping it
>>>        
>> if features
>>      
>>> are rendered? Often legend rendering is done separately
>>>        
>> from drawing, as two separate requests. Presumably you'd need
>> a something like a fake draw map option in the legend code to
>> make a drawing-like pass through the data. Could get expensive.
>>      
>>>
>>>        
>>    Yes,  it could be an expensive operation to do a fake draw
>> to get the legend. I am wondering if we could save something
>> when a draw is done and retrieve it for the legend if it
>> validates the current layers/extent  constraint.  Draw and
>> legend are separate process but come usually one after the
>> other so trying to take into account that fact might help.
>>
>> regards
>>
>>      
>>> Steve
>>>
>>> -----Original Message-----
>>> From: mapserver-dev-bounces at lists.osgeo.org
>>> [mailto:mapserver-dev-bounces at lists.osgeo.org] On Behalf Of
>>> Yewondwossen Assefa
>>> Sent: Thursday, June 10, 2010 7:24 PM
>>> To: 'MapServer Dev Mailing List'
>>> Subject: [mapserver-dev] MapServer legend functionality
>>>
>>> Hi all,
>>>
>>>     I was looking into possible solutions re. MapServer
>>>        
>> legend and the
>>      
>>> possibility to only draw a legend (icon and text) based on
>>>        
>> the current
>>      
>>> visible features.
>>> The idea is to have this functionality exposed through
>>>        
>> interfaces such
>>      
>>> as OGC GetLegendGraphic that can provide the drawing
>>>        
>> "context" (such
>>      
>>> as layers, bbox ...). The idea is to allow users to have a
>>>        
>> reasonable
>>      
>>> legend based on what they are drawing.
>>> Do others run into this and see it as a useful addition?
>>>
>>> best regards,
>>>
>>>
>>>        
>>
>> --
>> ----------------------------------------------------------------
>> Assefa Yewondwossen
>> Software Analyst
>>
>> Email: yassefa at dmsolutions.ca
>> http://www.dmsolutions.ca/
>>
>> Phone: (613) 565-5056 (ext 14)
>> Fax:   (613) 565-0925
>> ----------------------------------------------------------------
>>
>>
>> _______________________________________________
>> mapserver-dev mailing list
>> mapserver-dev at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/mapserver-dev
>>
>>      
>    


-- 
----------------------------------------------------------------
Assefa Yewondwossen
Software Analyst

Email: yassefa at dmsolutions.ca
http://www.dmsolutions.ca/

Phone: (613) 565-5056 (ext 14)
Fax:   (613) 565-0925
----------------------------------------------------------------