Layer get distinct function...

[Bart van den Eijnden]

Steve,

this could also be very useful for the WFS interface, which has a DISTINCT
function.

<ogc:Functions>
<ogc:Function_Names>
<ogc:Function_Name nArgs="1">MIN</ogc:Function_Name>
<ogc:Function_Name nArgs="1">MAX</ogc:Function_Name>
<ogc:Function_Name nArgs="1">COUNT</ogc:Function_Name>
<ogc:Function_Name nArgs="1">DISTINCT</ogc:Function_Name>
</ogc:Function_Names>
</ogc:Functions>

See also:

http://www.maptools.org/bugzilla/show_bug.cgi?id=351

Best regards,
Bart

> It can be costly in some cases but I can also see the immediate use for
> me in the time support where the user sends a request like Time=current
> (or Time=now).
>
>
> Steve Lime wrote:
>
>> Hi all: Tom's recent post about time and WMS reminded me of a feature
>> that might be useful for WCS/WMS and other interfaces. The ability to
>> get a list of distinct values for an attribute within a layer. At the
>> moment with WCS for example you have to explicitly enter all available
>> times in metadata. Works fine for a few but would get tedious quickly. I
>> could also see this as being a way to extend templates to be more
>> dynamic (e.g. produce a select list) and data driven. It would be very
>> helpful to be able to mine the data for that list. I'd like to propose a
>> msLayerGetDistinct function that would return an array of all unique
>> values for an attribute. What do folks think, other better ideas?
>>
>> Steve
>>
>
>
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> Assefa Yewondwossen
> Software Analyst
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> Email: assefa at dmsolutions.ca
> http://www.dmsolutions.ca/
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