[mapserver-users] snap-to scale

[Puneet Kishor]

I sort of understand what you mean... let's see...

On Thursday, May 16, 2002, at 05:06  AM, imap at chesapeake.net wrote:

>
> Over the past few years I been grappling with issues of tweaking
> mapfiles to get the various scale to render correctly while giving
> the user infinite zoom capability.  Its a tough task to make maps
> display with the correct labelling, line widths and annotation.
> Seems like the best mapfile configurations, are really big
> due to the granularity of the minscale/maxscale breakdowns for
> N layers...  and in particular there are alot of issues with
> annotation font placement which are extremely difficult to control
> with a minscale/maxscale configuration.  Do you know what I mean?

yes, this is a nuisance. in fact, it would be cool to do away with the 
mapfile completely... create everything on the fly... all the layer 
definitions, etc. on top of that, any layers you want to "identify" have 
to be duplicated as a highlight layer... the complexity very rapidly 
explodes.


>
> I am thinking about coming up with a scheme that will 1) take
> a set of extents and adjust them to conform to either a pre-set
> zoom levels or scales, or 2) re-design the apps to render using
> a center point and mapscale (or maybe miles/km conversion)
>
> Im thinking that if I set up 10 or so preset zoom levels, and
> round extents the conform specifically to my mapfile parameters,
> it would be easier to manage and improve the quality of the images
> rendered.
>

seems like a reasonable solution. keep in mind though, your scales will 
change depending on the screen resolution of the client and the size of 
the mapimage. I have setup a zoom bar that doesn't go to preset scales 
but computes any scale between 1 and maxscale on the fly. The 
zoomintervals are discrete, but I can setup a sufficiently large number 
of them that it is quite usable really. works quite well, though the map 
file is still a mess.

pk/