[Maplab-dev] [Bug 213] [SECTStudio-Classifier] Adding Classes at button vs. top of list

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http://www.maptools.org/bugzilla/show_bug.cgi?id=213





------- Additional Comments From spencer@dmsolutions.ca  2004-02-18 22:19 -------
this has to do with the way that mapserver renders classes.  You might expect it
to work the same way as all the other types of drawing, i.e. it draws each
object one after the other (like layers and styles).  This is not how classes
work.  Each feature in a layer is drawn according to the class that it fits
into.  This means that mapserver evaluates each class as it finds it and if the
layer fits the class (expression) then it will use the styles of that class to
render the feature and then move to the next feature.  This is the important
part to understand.  It will draw the first class it finds and never draw
another one.  This means that if you have two classes that could draw the same
feature, with two complementary styles (one is a fill and one is an outline for
instance) only one class will be used and you will see either the outline or the
fill depending on which class comes first in the map file.

So when you add a catch-all class at the top of the list, every feature will end
up being drawn by that class.  There is no 'on top' with mapserver classes ...

the debate to add rows before or after the selected one is semi-religious.  I
think that we will always get different opinions on this issue.  I believe that
this is a documentation issue and nothing should be done to change it.

Well, there could be one thing ... we could have two insert buttons ... an
insert before and an insert after button, which I have seen in OpenOffice table
functionality ...



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