[gdal-dev] OGR Feature Styles

Geo Aspects Development dev at geoaspects.com
Thu Jan 24 07:39:44 EST 2008


hi,

I have a couple of questions regarding feature styles in OGR.

Firstly, it appears that there is no way to count or list the names of  
styles stored in a StyleTable - the list is private and there are no  
methods to access it. So, for example, in a UI, I can't list the  
available styles by name for the user to choose from. Is this correct?

Secondly, the section in the documentation marked  "Feature Styles can  
be stored at 2 levels" suggests that a style can be defined at the  
dataset or feature level. In fact, there is a  StyleTable property for  
OGRDataSource, for OGRLayer and for OGRFeature, however, none of the  
drivers appear to use these tables (they simply store the style string  
directly in the feature without using a table), plus the StyleMgr only  
uses the one style table it has been initialized with (so you have to  
preload it from the dataset, layer or feature) - which means that "all  
that stuff should be transparent to the OGR client " is not exactly  
the case ie If I want to look up a style name (as denoted by an @name  
in the style string) I need to search the style tables stored in the  
feature, then the layer and  then the dataset myself?

Thanks
Tim


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