[OSM-dev] Basic GPX parser in OpenLayers

Christopher Schmidt crschmidt at metacarta.com
Thu Oct 18 19:18:01 BST 2007

On Thu, Oct 18, 2007 at 07:11:57PM +0100, Shaun McDonald wrote:
> That is a fairly common compression ratio in my experience. Sometimes  
> I'm getting an even better compression, depending on where I've been  
> and the type of route/traffic.
> >
> >Since the point counts are available in the GPX tracklog page (it
> >seems), hopefully we can at least stick it in there for GPX tracklogs
> >with less than some number of points -- 1000 is ~2s to render, whereas
> >12000 was 90s, so if I do some speed improvements on it, maybe ew can
> >have support for 1000-5000 points or so.
> How about using gpsbabel to reduce the point count? In many instances  
> you just want to see roughly where the track went, so if it is  
> reduced to 1000 points, then in many use cases it could still be useful.

Line simplification is one way to limit points, but obviously it can't
be done with much effect in the browser when a large chunk of the
cpu time is processing time -- it would just make things slower. I can't
speak to whether OSM would want to have line simplification done on the
server, but perhaps someone else can.

Christopher Schmidt

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