Looking at the the hint "Hints.PRESERVE_TOPOLOGY" indicates you mean the 
generalization should take place in the FeatureSource ?. Would be consistent 
with the handling of image pyramids. 

I thought the "Hints.GENERALIZATION_DISTANCE" is enough and the feature 
source returns a set of valid geometries which are the base for 
generalization for Rendering/WMS. 

Anyway, we could choose, your decision. 

All other things are ok for me. 

 

 

 

Andrea Aime writes: 

> Hi,
> with Christian we've discussed this topic almost to death,
> let me summarize and ask for final feedback on the topic. 
> 
> What I propose is to add two new FeatureSource Hint,
> - Hints.GENERALIZATION_DISTANCE, expressed a a double,
>    intended to be a hint of the minimum distance
>    between two subsequent points in the generalized output,
>    or to say it another way, an indication of how much
>    the geometry shape can be altered as a result of the
>    generalization (anybody cares to word this better?)
> - Hints.PRESERVE_TOPOLOGY, a boolean, intended to specify
>    whether we can accept topologically invalid geometries
>    as a result of the generalization 
> 
> As usual the feature source will indicate the support
> for the two hints by advertising them into ... 
> 
> The two use cases for these hints are for rendering and
> for WFS output. We assume a generalizing
> feature source can get some significant speed benefits
> by doing in datastore generalization, for example:
> - a spatial database with a fast on the fly generalization
>    routine that results in less data transfer from the
>    database to the gt2 code
> - a datastore that has pre-generalized data sets (vector
>    data pyramid) and thus, can cherry pick the proper
>    version to pick and use 
> 
> The topology preservation is usually not required for
> rendering, and can open the door to quicker on the fly
> generalization routines, whilst we definitely want
> topology preserved geometries if we're serving them out
> in WFS. 
> 
> We want to introduce these two new hints in gt2 2.5.x
> and trunk. 
> 
> Opinions, feedback?
> Cheers
> Andrea 
> 
>  
> 
> -- 
> Andrea Aime
> OpenGeo - http://opengeo.org
> Expert service straight from the developers. 
> 
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