A question of scale

[Frans Knibbe]

Thanks Bart, this offers a clear explanation of the matter. I did search 
the archive but the word 'scale' is very common, I'm afraid.
In fact there is already some information on this matter in the MapFile 
Reference:

RESOLUTION [int]

    Sets the pixels per inch for output, only affects scale computations
    and nothing else, default is 72

Nonetheless, I think it would be a good idea to rename 'MINSCALE' and 
'MAXSCALE' to  'MINSCALDENOMINATOR'  and 'MAXSCALEDENOMINATOR'. Or let 
those keywords be synonyms for backward compatibility. Not only would 
the 'min' and 'max' bits be less confusing, it would also be clear the 
scale definition as found in the WMS 1.3 specification is used by MapServer.

Regards,

Frans


Bart van den Eijnden wrote:

>Frans,
>
>there are so many explanations from Ed McNierney on this issue in the Mapserver archive. Among others:
>
>http://mapserver.gis.umn.edu/data2/wilma/mapserver-users/0211/msg00186.html 
>
>http://mapserver.gis.umn.edu/data2/wilma/mapserver-users/0208/msg00056.html 
>
>And OGC already left the ScaleHints at WMS 1.3 ...... and replaced it with MinScaleDenominator and MaxScaleDenominator which is basically what Mapserver has. See also:
>
>http://mapserver.gis.umn.edu/data2/wilma/mapserver-users/0401/msg00594.html 
>
>Best regards,
>Bart
>
>Bart van den Eijnden
>Syncera IT Solutions
>Postbus 270
>2600 AG  DELFT
>
>tel.nr.: 015-7512436
>email: BEN at Syncera-ITSolutions.nl
>
>  
>
>>>>Frans Knibbe <frans at GEODAN.NL> 22-9-2005 15:11:50 >>>
>>>>        
>>>>
>Hello,
>
>Currently I am setting minimum and maximum scales for layers and classes 
>in the map file. This works leads me to the question how scale is 
>defined in mapserver. I could not find it in the documentation. Does 
>anyone know what is meant by scale in the context of the MINSCALE and 
>MAXSCALE keywords?
>
>And wouldn't it be better to use scalehints (as defined by the OGC) in 
>stead of scale? That would also make the settings less confusing because 
>MINSCALE is used for maximum scale and vice versa.
>
>Regards,
>
>Frans
>
>
>
>  
>