[mapserver-users] classitem and class expression in itasca demo

[Patrick Stanistreet]

I have been working with the itasca demo trying to learn mapserver and gis.

I have simplified the demo.map  file to a single layer which displays the
state in outline.  The layer is ctybdpy2 and I have used the existing 
extents
from the demo.map file.  I have also compiled shapelib and verified the
extents from the file ctybdpy2 using shpinfo..

The classitem is  cty_name and the class expression is  Itasca.  Using 
dbfdump
I can see the column headers and the cty_name column has many other cities
in other rows.

I would have guessed that I could change the class expresssion value to 
another
city but when I do that the map does not display.  Going back to
cty_name Itasca works  fine. I  have been able to substitute another column
for the same city , forgot what the column name is but it is a short form of
the city name and the class expression ITAS works.  But again  changing
to any other city doesnt work.

Also I have noted that the dbfdump shows multiple rows with the same 
city name,
so thinking that could be part of the problem I have tried to use a city 
with
a unique row but it makes no difference.

The actual reason for all this is that I have downloaded a shapefile map of
California and verified its extents using once again shpinfo.  Also I 
have looked
at the the dbfdump information and tried substituting a column  field  
classitem and class expression from the dbfdump info and the calif. map
into the demo.map file but it gives the same results.  Map doesnt display.

Sorry for the repeat questions here but this has stopped me cold.