[webmap-discuss] WMS Requests: Rounding BBOX

Steven M. Ottens steven.ottens at geodan.nl
Thu Sep 21 06:20:01 EDT 2006


Christopher Schmidt wrote:
> Today, an OpenLayers user asked me why we weren't rounding BBOX values
> in our tiled image requests, since it was causing problems with his
> reverse proxy caching to have OpenLayers not do so. The primary reason
> this isn't done at the moment is that I couldn't pick a good value to
> use :)
>
> 6 decimal places seems to be a generally good value to cut-off at when
> working in degrees: that gets you down to half-meter accuracy (I 
> think?). Does anyone have any other thoughts on this? How have you
> addressed rounding BBOX requests in your own applications?
6 decimal places for lat/long is fine. I don't think we need to be able
to give bounding boxes in mm on lat/long systems anyway. But 6 decimal
places for projected ones is a bit overkill. Can you make sure that
those bounding boxes are rounded in a more sensible way?

Steven

-- 
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