different tiling methods

[Jeff Portwine]

Hi Everybody,

I have a general question for my own education, it doesn't directly pertain to anything I'm working on right now.    I was just wondering if anybody could explain to me the difference in different ways of tiling map images?     In my current project, I had several large layers such as road layers and water layers that I tiled in order to make them faster and more resource friendly... The method I used was:

-tile4ms <data.txt> <tile name>   
(where data.txt is a list of all the shapefiles being included in the tiling, since tiger data comes in about a zillion files)
-shptree <tile name>
-cat <data.txt> | xargs -n 1 shptree

The way I understand it, this combines all the pieces into one shapefile, tiles them, and spatially indexes them...  is that correct?   

In a recent post I also saw a pointer to Steve Woodbridge's shp2tile utility which it seems does much the same thing... the main difference being from the sounds of it that it doesn't put a lot of shapefiles together, but rather splits a single large shapefile into tiles and then indexes them.   How is this different from the first method, and how does it affect resources and rendering speed?   Or is the only real difference the one I noted where you are sticking multiple shapefiles together one way and only using one original shapefile the other way?

Are there other methods of tiling that behave differently or that you might use for different situations?

Thanks everybody,
Jeff
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