[OSM-dev] How to show isochrones on slippy map

yvecai yvecai at gmail.com
Sun Aug 21 09:22:04 BST 2011


On 20. 08. 11 20:33, Josh Doe wrote:
> So now that I'm figuring out the necessary bits to generate isochrones
> (or rather distance isolines) from OSM+pgRouting+GRASS, I'd like to
> put this on a little web app to allow users to specify an arbitrary
> start point and distance (and later select from several profiles). I'm
> not sure what's best/fastest, to just send a raster to be overlaid on
> the OSM basemap, or to send it as a vector.
Using a vector overlay with openlayer, you can make your isochrones 
selectable, highlight-able and clickable, so you can deliver related 
informations in popups: user experience may be richer and easier.
However, with complex vector features, such an overlay can be heavy to 
display on small clients. From your example on the wiki, it seems OK, 
though.
> I've done very little with
> OpenLayers, so I'm wandering through the woods quite a bit here. I was
> thinking of copying from the pgRouting workshop (i.e. use PHP process
> clicks and to deliver data).
>
> You can see an example map here:
> http://wiki.openstreetmap.org/wiki/Safe_Routes_to_School_Mapping_Toolkit#Technical_details
>
> Any pointers to similar implementations would be appreciated, either
> for inspiration or code reuse.
Although it is a little bit messy, you can find some useful code with 
vectors and routing on 
http://dev-yves.dyndns.org/pistes-nordiques-backend/index.html.
You will probably find at http://openlayers.org/dev/examples/ all that 
you need for your app.

Yves




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