user restrictions / tiles

[Stephen Lime]

I guess you could use classes for this. That is, assuming there is an owner attribute
for each shape you could add to the normal class expressions "... AND '[OWNER]' == 'user'".
You then have to build those expressions assuming you have multiple users. Couple of
ways to do that depending on how anal you are about security;

 - use CGI vars to change expressions dynamically
 - use mapscipt

The next version of MapServer will allow you to substitute CGI vars directly into expressions
so you could write "... AND '[OWNER]' == '[CGI_OWNER]'" where CGI_OWNER is a
variable in your HTML form. MapScript gives you the most control obviously. You could
build user specifc mapfiles as needed. That way you could store user data in separate
shapefiles. You also have access to a richer set of authentication schemes.

Very large datasets are more efficient in tiled format, for the most part. Expressions are
supported on tiled shapefiles. Normal query (by point, area or rect) is not supported (yet!)
on tiled shapefiles. Coming soon though.

Steve

Stephen Lime
Internet Applications Analyst

Minnesota DNR
500 Lafayette Road
St. Paul, MN 55155
651-297-2937

>>> Matthias Schulz <schulz at gaf.de> 01/22/01 02:57AM >>>
1.
Is there a way to define the data of a shapefile shown on the map by
using an attribute query? I want the user to log in and show only the
information he is allowed to see, i.e. setting a query definition to the
shapefile(s) with mapscript. Does anyone have an example for this?
2.
For large datasets I assume it is faster to work with tiles, is that
correct? Can I combine working with defining the shown data by a query
as in point 1 and working with tiles?

Thanks a lot,

Matthias

--
Matthias Schulz
GAF mbH   Arnulfstr. 197   80634 Muenchen   Germany
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