[OSM-newbies] Rendering on the PC

Serge Wroclawski emacsen at gmail.com
Sun Apr 11 20:12:14 BST 2010


On Sun, Apr 11, 2010 at 1:22 PM, john whelan <jwhelan0112 at gmail.com> wrote:
> This may not be the ideal place to post the question but I'll ask it anyway.
>
> When I use JOSM it downloads the tiles I'm after then uploads the changes
> I've made afterwards.

> The idea would be an OSM aware program that sits on the PC similar to Google
> Earth.  It would grab the information from OSM and cache it for next time.
> Next time it would query to get any updates and then just download the
> updates.

That's not as easy as it sounds.

There's no current support in the API (the communication protocol
between the client and server) for a client to request updates to a
certain area by time. In other words, you can't ask for a bounding box
as per a certain date at this time.

That's why there's no nice way to have an API cache (which is
essentially what you're asking for). There might be ways to get around
it, but you'd end up doing so much work that it would be significantly
more work on both the client and the server end in order to save what
would probably be a negligible amount of network traffic.

> The program would also allow items to be selected for display, same concept
> as Google Earth, place names, cycle routes etc.  This would allow a smaller
> packet to be returned to the PC if we only sent the requested information.

You can currently request only some data from the server, and since
you're using JOSM, I believe you can already use this functionality.

> The advantages would be lower server and internet traffic.

Traffic isn't the only measurement of "work", but as this would
require a significant amount of work to add to the API, I don't think
it'll happen soon.

> So the question is is there such a program today?

You can do most of what you describe now with JOSM, including the
rendering I believe.

> If not how does one nudge someone to build it?

We're generally a community of "doers". If you feel strongly about it
needing to get done, then  roll up your sleeves and work on it. We'll
be here to help you.

- Serge




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