[mapguide-internals] Updated MapGuide RFC 14 - CartographicStylization Engine

Ben Trumbore ben.trumbore at autodesk.com
Thu Feb 22 15:22:12 EST 2007


I have a few questions about the updated schemas (version 5):

* Now that the symbolization elements must be included in the layer
definition schema, will it be possible for both the layer and
symbolization resource schemas to reference (i.e. include) a single
schema for the symbolization elements?  I'm no XML expert - maybe the
answer to this is obvious.

* How does the new LineWeightContext interract with the SizeContext of a
SymbolInstance that refers to a LineUsage?  Does SizeContext only affect
point symbols and not lines?  What is the default for LineWeightContext?

* By removing the Label element from CompositeRule, that class will not
cleanly derive from the Rule class in MdfModel.  We have competing
interests here: having the new classes fit into the existing object
model, and not providing two (incompatible) method for labeling the same
features.  We could, of course, derive from Rule just ignore the Label
member.  Thoughts?

* Speaking of labels, the RFC gives several examples of graphic being
laid out along a line symbols (plain text labels would presumably be
similar), but no examples of labelling for points or polygons.  It isn't
clear to me how the position of such labels is controlled.

I assume DrawLast helps make labels show up on top of features.  That
name might be a bit misleading - is there something wrong with just
flagging it as a label?

How do we specify that a text symbol is meant to be dynamically placed
near a point feature (as it currently does) rather than being fixed at
the feature location?  If CheckExclusionRegion is false for a point
layer, is the symbolization placed right at the point (factoring in the
insertion point, etc).

Most of the AreaUsage elements seem relevant to specifying a fill
pattern for polygons, rather than to specifying a label that is
dynamically centered in the visible part of the polygon.  How do you
tell the difference between fill and and label here?  Does the
OriginControl element have anything to do with this?

* Do I correctly understand that all "overpost" elements have been
replaced with a notion of an "exclusion region", and that symbolizations
can now say "Don't let anyone overpost me" and "I will overpost anything
I please"?  If so, which of those declarations takes precedence?

* Can CompoundSymbols be stored as resources, or only SimpleSymbols?
The documentation for SymbolReference doesn't say.  The schema only
permits a CompoundSymbol to contain SimpleSymbols as children, and those
SimpleSymbols can be specified with a SimpleSymbolReference (essentially
the same as a SimpleSymbolReference, right?).  If CompountSymbols can be
resources, it's easy to imagine someone referring to a CompoundSymbol as
a child of a CompoundSymbol.  Would we treat that as bad data?  Is there
a good reason why we can't allow this?  It certainly isn't essential
functionality, and you've probably thought it through, so I'm just


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