Hi Jesper,
As a workaround (unless this was the intended design), you can use the
following approach:
SCALETOKEN
NAME "%ne_scalerank%"
VALUES
"0" "([scalerank] < 10)"
"1000" "([scalerank] < 8)"
"10000000" "([scalerank] < 5)"
END
END
FILTER "%ne_scalerank%"
Seth
--
web:https://geographika.net & https://mapserverstudio.net
mastodon: @geographika@mastodon.social
On Thu, Feb 13, 2025, at 12:31 PM, Seth G via MapServer-users wrote:
> Hi Jesper,
>
> This looks like a bug - it should work as you expect it to.
> Could you log an issue at https://github.com/MapServer/MapServer/issues ?
>
> Seth
>
> --
> web:https://geographika.net & https://mapserverstudio.net
> mastodon: @geographika@mastodon.social
>
> On Wed, Feb 12, 2025, at 3:13 PM, Jesper Kempe via MapServer-users wrote:
>> Hi
>>
>> I am trying to show different levels of details based on zoom level in a map
>> based on Natural earth 10m data (ne_10m_lakes.zip from
>> https://www.naturalearthdata.com/downloads/10m-physical-vectors/) using the
>> attribute scalerank in the shape file.
>>
>> My plan was to use SCALETOKEN to replace the value in a FILTER with the
>> current max scalerank to use.
>> But I cant get it to work. Nothing is shown in the map.
>>
>> Should it be possible to use a scaletoken in a filter expresssion?
>>
>> Looking at https://mapserver.org/development/rfc/ms-rfc-86.html#discussion
>> it looks like it at least was planned to work?
>>
>> Now I get errors like this in the log file:
>>
>> [Wed Feb 12 13:50:20 2025].23938 replacing scaletoken (%ne_scalerank%) with
>> (5) in layer->filter (ne_10m_lakes) for scale=221471921.250000
>> [Wed Feb 12 13:50:20 2025].24460 msEvalExpression(): General error message.
>> Cannot evaluate expression, no item index defined.
>> [Wed Feb 12 13:50:20 2025].24474 msEvalExpression(): General error message.
>> Cannot evaluate expression, no item index defined.
>> [Wed Feb 12 13:50:20 2025].24482 msEvalExpression(): General error message.
>> Cannot evaluate expression, no item index defined.
>>
>> Using this mapfile:
>> MAP
>> CONFIG "MS_ERRORFILE" "ms_error.txt"
>>
>> STATUS ON
>>
>> PROJECTION
>> "init=epsg:4326"
>> END
>>
>> EXTENT -180 -90 180 90
>>
>> WEB
>> METADATA
>> "wms_title" "WMS Demo Server"
>> "wms_srs" "EPSG:4326"
>> "wms_enable_request" "*"
>> END
>> END
>>
>> LAYER
>> DEBUG 5
>> NAME 'ne_10m_lakes'
>>
>> TYPE POLYGON
>> PROJECTION
>> "init=epsg:4326"
>> END
>> EXTENT -180 -90 180 90
>> DATA "ne_10m_lakes.shp"
>>
>> SCALETOKEN
>> NAME "%ne_scalerank%"
>> VALUES
>> "0" "10"
>> "1000" "8"
>> "10000000" "5"
>> END # VALUES
>> END # SCALETOKEN
>>
>> FILTER ([scalerank] < %ne_scalerank% )
>>
>> CLASS
>> STYLE
>> OUTLINECOLOR "#647078"
>> WIDTH 1
>> COLOR "#EBEEF0"
>> END
>> END
>>
>> END
>>
>> END
>>
>> For this request
>> https://myserver/wms?&service=WMS&request=GetMap&layers=ne_10m_lakes&styles=&format=image%2Fpng&transparent=false&version=1.1.1&map=ne_10m_lakes.map&height=512&width=512&srs=EPSG%3A4326&bbox=-180,-90,180,90
>>
>> Worth noting is if I replace FILTER ([scalerank] < %ne_scalerank% ) with
>> FILTER ([scalerank] < 5 ) in the mapfile it works fine.
>>
>> Anyone with thoughts or ideas on how this can be solved?
>>
>> I am on Mapserver 7.6.4.
>>
>> Thanks,
>> Jesper
>>
>> _______________________________________________
>> MapServer-users mailing list
>> MapServer-users@lists.osgeo.org
>> https://lists.osgeo.org/mailman/listinfo/mapserver-users
>>
>
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