OGR Autostyling and other providers, styling RFC?

Daniel Morissette dmorissette at MAPGEARS.COM
Mon Nov 19 17:26:43 EST 2007

Tamas Szekeres wrote:
> But my other problem related to this is that the style info is
> assigned to the features but we cannot utilize layer level styles at
> the data source. Therefore loading the styles happens in that time
> when the features are actually drawn and the last loaded style is
> preserved at layer level. Currently I have approx 3000 OGR layers with
> syle info but I guess all of them use the same style for each feature
> actually. This behaviour causes some known issues (like the problems
> around rendering those layers in the legend) that have been been
> discovered early but haven't been addressed yet.

FYI Tamas, "styles at the layer level" was part of the original "OGR 
Feature Style" design but was never implemented... so if we want to go 
that route we got a bit more work to do, both in OGR and MapServer.

Using a style table at the layer level and linking features to styles by 
style-id is an extremely powerful way to do rendering. Combine style 
tables with the concept of priority levels and you can do even more 
powerful things. We had implemented that approach in a cartographic 
editing software in a previous life before my webmapping days and that's 
why I had included section 2.7 in the OGR Feature Style document 
(http://gdal.org/ogr/ogr_feature_style.html)... but as I wrote above 
this was never implemented in OGR.

Daniel Morissette

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