[mapserver-users] snap-to scale

[Joe Bussell]

I have started to make a first pass at a solution similar to the one you
are discussing.  I have two mapfiles, one for raster generation at fixed
zoom levels, the other for live requests.  I have created sevel scales
that are displayed and use javascript to insure that my extents and map
pixel dimensions match up to one of my rastered scales (with the
exception that at highly zoomed in scales I provide a live map).  I have
found that it is more useful to think of maps in terms of a center and
what I call a Span, which describes the size of the image in decimal
degrees.

I like what you are thinking about though.  It seems that I wrote a lot
of code that will never see reuse, which is never a good plan.  I would
like to continue this thread...

Joe Bussell
On Time Systems


On Thu, May 16, 2002 at 06:06:56AM -0400, 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?
> 
> 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.  
> 
> So anyway, I thought I would solicit some ideas to come up with the
> simplest solution to make mapserver snap-to preset mapscales that
> align with my mapfile layer objects.  hmmm
> 
> Regards,
> 
> Chris Stuber (mapsurfer)
> Silicon Mapping Solutions, Inc
>