ENC: [Mapserver-users] What is the resolution item on the mapobject?

[Murilo Lacerda Yoshida]

-----Mensagem original-----
De: Murilo Lacerda Yoshida [mailto:murilo.yoshida at agx.com.br] 
Enviada em: segunda-feira, 21 de junho de 2004 19:54
Para: 'Steve Lime'
Assunto: RES: [Mapserver-users] What is the resolution item on the
mapobject?

  Thanks Steve, that clears my ideas...
  I was in doubt about the resolution member because somewhere in
mapscale.c it is used to calculate the scale if the scale is in feet
units.
  But if it is not used, and I use meters anyway, that doesn't really
matters.
  Thanks,
    Murilo

-----Mensagem original-----
De: Steve Lime [mailto:steve.lime at dnr.state.mn.us] 
Enviada em: segunda-feira, 21 de junho de 2004 16:58
Para: murilo.yoshida at agx.com.br; mapserver-users at lists.gis.umn.edu
Assunto: Re: [Mapserver-users] What is the resolution item on the
mapobject?

There's very little reason to use the resolution parameter. The only
reason
it was ever added was for the case when you create very high
resolution
images for printing. In those cases if you stuck with the default
resolution
AND used scale values label/layer display or symbol scaling you might
not
get what you hoped for. So, let's say you want to make a high
resolution
version of what the user sees onscreen. Well, you might change the
resolution so that the computed scale is consistent between the
monitor
and the printed page. The scale value number is mostly useless except
for relative things like scaling symbols or turning things on and off.

Resolution is used for computation of a numeric scale value and not for

scalebar generation.

Does this help?

Steve

>>> "Murilo Lacerda Yoshida" <murilo.yoshida at agx.com.br> 6/18/2004
4:29:30 PM >>>
  Hi all,
  I was reading the mapscale.c. In the calculateScale method it uses a
resolution member of the map object.
  Then I looked at the mapfile documentation, it says that the
resolution member is used to calculate scales, and that its default is
72 pixels per inch.
  I normally do not define this member in my map files.
  Ok, so that means that all my scales are calculated by considering
that 1 inch equals 72 pixels?
  If I use php/mapscript, should I refresh this member every time my
extents change so I get the actual scale?
  I am a little confused about this.
  Thanks,
    Murilo