[OSM-dev] Cartagen - client-side vector based map renderer, dynamic maps
Stefan de Konink
stefan at konink.de
Thu May 7 20:24:12 BST 2009
Jeffrey Warren wrote:
> were you thinking of the thru-flash technique for sockets?
I have two options; I was indeed looking at the flash technique for
native protocol access. Alternatively the Cherokee Webserver has its own
'dbslayer' implementation this allows an SQL database to be queried over
HTTP and outputed in the common formats [json/xml/cvs/...]
> I'd love to
> help out if I can. Right now, Cartagen doesn't use sockets, but small
> Ajax requests every 1/3 of a second. Latency is low but not quite
> realtime... it's within about a second but depends on the size of the
> plot requested of course. I've been avoiding Flash because it's not
> available on the iPhone or Android, and it'd be nice to have almost the
> same renderer/editor codebase on mobile devices and PC.
I don't want to reinvent the wheel, so I will checkout how you build
this thing and probably hook in some code.
> Just curious, how does Mapnik or Omsarender do it? Surely they don't
> actually render every node of a way for very large bboxes?
In the default Mapnik case polylines are fetched, so that is basically
an operation that already has a materialized linestring. Since the
tables know what type the line will be it is just a draw this line at
that point. [A bit more complex due to layer = ...]
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