making efficient map layers

[Frank Warmerdam]

On Tue, 22 Mar 2005 10:52:32 -0500, Jeff Portwine <jdport at veritime.com> wrote:
>
> Thanks for the information...
> I can write a script I'm sure, but I have never used the ogr2ogr utility and
> I'm not sure how it works... is there documentation for that?

Jeff,

OGR utility documentation is available off the OGR web page at:

  http://www.gdal.org/ogr

>  Or if Mapscript could be used that might be even
> better, though I really don't know how I could create new shapefiles from
> old ones but I'll look into it.

I don't know how to do that off hand in mapscript, but I think it has
the ability to create shapefiles.  You might have to create all the fields
manually.

> Is it possible using ogr2ogr to output (as in your example) CFCC=A13 from
> every county shapefile into a single shapefile, or would I have to create
> separate output shapefiles for every county and then tile them?

As Stephen Woodbridge mentions, having lots of little shapefiles
with a tileindex isn't a bad thing.  However, you can use the
ogr2ogr -append  and -update to open an existing shapefile in update
mode, and append to the end of it if you really want to merge things.

Best regards,
--
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent