[mapserver-users] .map

woodbri at swoodbridge.com woodbri at swoodbridge.com
Thu Sep 19 18:06:35 PDT 2002


John,

There are a few of ways to look at this problem.

One is think of every shape file as a layer and have a bazillion 
layers  -  this may be the right way, but there may be a better way.

An other way is to think of the data as a smaller number of sets of 
common objects where each set represents a layer in the map file.

Let say you have a set of telephone poles and every day another city 
or region reports on with their telephone poles in their own shape 
file. So now you have to include that new shapefile in the map. Bang! 
need another layer - right?  ... Wrong!

I have a Tiger/Line Mapserver running. The Tiger data is organized by 
counties, about 3300 of them in the US, every county has about 10 
different shapefiles, that would make about 33,000 shapefiles, but I 
only have 10 layers to define the 10 types of data in the mapfile. If 
I added another county and its 10 new shapefiles, I would not need to 
add any new layers.

The trick is to make a tileindex for each layer that points to the 
the 3300 files that represent a single layer. If I add a new shape 
file to the map, I update the tileindex to include a reference to the 
new file and I never touch the mapfile. This can easily be automated 
with a little scripting. In example above of telephone poles it would 
work the same way. You copy the new shape files to the map data 
directory and run a utility to add its record to the tileindex.

I hope this makes sense,
  -Stephen Woodbridge
   http://iMapTools.com

On 19 Sep 2002 at 16:17, John Bennett wrote:

> I'm new to this, therefore a simple question.
> 
> I have a large dataset that is being added to daily, full of
> shapefiles and Gifs. For displaying these files using Mapserver is the
> protocol to update the .map file every time the database is updated
> (one big .map file, I don't think so, too big eh!) or make a new .map
> dynamically for each user depending on their request? Thanks for the
> past help. John
> 
> 
> 





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