[Mapserver-dev] Generic tiling (for shapefiles and rasters)...

[woodbri at swoodbridge.com]

On 9 Mar 2004 at 22:49, Steve Lime wrote:

> The modifications I'm talking about should have no effect on file-based
> versus directory-based access. The location (or TILEITEM) contents are
> applied to the layer that is tiled regardless of the where the tileindex
> is defined. Your old mapfile would still work. You could re-write as
> 
> LAYER
>   NAME tiger-tile
>   DATA tiger-tile
> END
> LAYER
>    TILEINDEX "tiger-tile"
>    DATA "roads"
> END
> LAYER
>   TILEINDEX "tiger-tile"
>   DATA "waterpoly"
> END
> 
> A bit more verbose but now you can do filtering within your tiles. For 
> example, you could take a single county out of production. Or you
> could store multiple years worth of data within the same tile and could
> specify a particular year at runtime.

Would achieve the filtering using the FILTERITEM in the tile layer?
Could you use CLASS say on a polygon layer where you colored the 
polygons based on year, for example?

> Will you be willing to test?

Yes, if I have time I would be happy to. Work has got me running flat 
out but I have a special case of needing only one 1 states worth of 
Tiger data, and just made a special tileindex for that. It would have 
been nice is we could have just filtered the existing index and had 
one less file to worry about keeping up to date. I should be able to 
adapt this mapfile to a test.

-Steve

> > -Steve W.
> 
> Steve
> 
> On 8 Mar 2004 at 17:06, Steve Lime wrote:
> 
> > Hi Folks: As I've been putzing with enhanced tiling support I've been
> > trying to generalize things
> > so that one wouldn't be limited to simply shapefile tile indexes. For
> > raster data that shouldn't be
> > an issue using another LAYER as a tile layer. This would allow you,
> for
> > example, to store your
> > tileindex in PostGIS and reference images on the file system. For
> > shapefiles it's not that simple
> > though because of this need to open one tile as a template (to get
> item
> > names and such). I can'd
> > find an easy way to retrieve, for example, the 1st record in a layer.
> > (For rasters this isn't an 
> > issue since we don't need a template.)
> > 
> > So, there are a couple of options:
> > 
> >   - say the hell with non-shapefile tile indexes for shapefiles, but
> > allow them for rasters
> > 
> >   - figure out a method to retrieve the nth element of a datasource
> > (not by ID, but by position)
> > 
> >   - retool the msLayer... functions and move the msLayerWhichItems
> > functionality someplace else
> > 
> > I'm partial to the first one. I can't imagine anyone using
> > non-shapefile tile indexes with shapefiles 
> > (I mean, most folks would put everything in PostGIS or SDE). Raster
> > data are where that functionality
> > makes sense.
> > 
> > I just want to run the idea by folks to make sure I'm not overlooking
> > some obvious solution.
> > 
> > Steve
> > _______________________________________________
> > Mapserver-dev mailing list
> > Mapserver-dev at lists.gis.umn.edu
> > http://lists.gis.umn.edu/mailman/listinfo/mapserver-dev
> > 
> 
> 
> 
> 
> Stephen Lime
> Data & Applications Manager
> 
> Minnesota DNR
> 500 Lafayette Road
> St. Paul, MN 55155
> 651-297-2937
>