[mapserver-dev] RFC: GMaps API for mapserv

[Paul Spencer]

On 10-Apr-08, at 5:33 PM, Stephen Woodbridge wrote:
> Paul Ramsey wrote:
>> On Thu, Apr 10, 2008 at 1:07 PM, Stephen Woodbridge
>> <woodbri at swoodbridge.com> wrote:
>>> It seems that the meta-tiling and labeling issues will need to be  
>>> addressed
>>> eventually, so I think some discussion of how they would be done  
>>> from a
>>> design point of view should be undertaken. If these can not be  
>>> easily solved
>>> in this architecture then that might indicate a problem.
>> Metatiling implies caching, since you'll necessarily be producing way
>> more tiles for each request than you need, you should store the  
>> spares
>> for the future. And I don't think we want to go there. At least, some
>> folks don't want to go there.
>
> Yes, I agree with the fact the metatiling is out of scope. I think  
> the point that I did not make so clear is that assuming someone  
> wants to do metatiling, say using some script or tilecache or  
> whatever. Is there anything in the implementation or design that  
> would prevent one from generating metatiles and chopping them up via  
> a script and storing them somewhere outside of mapserver? If yes, is  
> removing that within the scope of things or not?

I think that you should do a couple of things differently in mode=gmap:

* Steve Lime just added a processing option to enable mapserver to  
calculate label positions before features are clipped.  With PARTIALS  
TRUE, this should eliminate the label problems to a large extent when  
producing tiles since adjacent tiles should put the label in the same  
place (relatively speaking) and labels should end up continuing nicely  
across tile boundaries.  So this processing option and PARTIALS TRUE  
could be forced on in this specific mode

* draw map tiles a bit bigger and trim the result to reduce edge  
effects.

If you did this, with an apache module, meta tiles would be a thing of  
the past - well maybe not, but it would go a long way to avoiding the  
need for them.

Also, I think you should call it mode=tile :)

And ... +1!

Cheers

Paul
__________________________________________

    Paul Spencer
    Chief Technology Officer
    DM Solutions Group Inc
    http://www.dmsolutions.ca/