[mapserver-dev] MapServer legend functionality

[Yewondwossen Assefa]

On 11/06/2010 1:53 PM, Bart van den Eijnden wrote:
> Personally I like extending GetLegendGraphic with an extra BBOX parameter. This way it will be easier to have generic clients. Other SLD WMS implementations can just ignore the extra BBOX parameter and act as they would normally do.
>
>    
   I see your point. I guess we need to support at least the BBOX but 
also all other parameters that are supported in the GetMap.  I am 
wondering if overloading   GetLegendGraphic would not create confusion 
for users with existing parameters used for a regular GetLegendGraphic.  
Beside the OGC interfaces, It should also be possible to expose this 
through MapScript.

> Best regards,
> Bart
>
> On Jun 11, 2010, at 7:32 PM, Yewondwossen Assefa wrote:
>
>    
>> 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
>> ----------------------------------------------------------------
>>
>>
>> _______________________________________________
>> 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
----------------------------------------------------------------