[HOT] next HOT tech chat

Wed Jul 17 04:46:16 UTC 2013

Hi Pierre,
if you are doing your workshop with JOSM, a short term and low-tech
solution is to use the caching feature of JOSM. As Paul mentioned, you have
to check the terms of use of the imagery you are using to make sure you are
allowed to cache it. You can find the feature in JOSM in
Edit->Preferences->WMS/TMS
tab->Settings. There is a path at the bottom. When you browse around an
area, the tiles are cached in this folder, once you have covered the area
you want (for each zoom level) then you can copy this folder to the other
computers in the right place (check the path in the preferences or you can
set the path to where you copied the files). Also, I don't remember exactly
but you may also need to do what is written under the section "Caching" on
this page http://josm.openstreetmap.de/wiki/Help/Menu/Imagery  to make sure
the cache isn't deleted.

Cheers,

Vivien

On Tue, Jul 16, 2013 at 12:31 PM, Pierre Béland <pierzenh at yahoo.fr> wrote:

> HOT is presently deploying four field teams in Burkina Faso, Chad, Togo
> and Senegal. As it is often the case in these countries, internet bandwith
> is a significant problem. We are already experimenting problems in Togo.
>
> What type of  "not too techy" solution could be implemented immediately to
> respond to internet communication problems of a classroom with up to 20
> computers ?
>
> As we said yesterday at the Tech WG, the most significative improvement
> for field teams would probably be to cache the Imagery.
>
> What short term solution would you propose for this?
>
> Pierre
>
>   ------------------------------
>  *De :* Harry Wood <mail at harrywood.co.uk>
> *À :* Paul Norman <penorman at mac.com>; 'Yantisa Akhadi' <yantisa at gmail.com>;
> 'Mikel Maron' <mikel_maron at yahoo.com>
> *Cc :* "hot at openstreetmap.org" <hot at openstreetmap.org>
> *Envoyé le :* Mardi 16 juillet 2013 10h39
> *Objet :* Re: [HOT] next HOT tech chat
>
>
>
> > So, there's a few different things you could cache.
> >
> > One is imagery/tiles. For tiles it's a well-solved problem, tile.osm.org
> > uses a bunch of squid caches and the configuration is all at
> > http://git.osm.org/chef.git/tree/HEAD:/cookbooks/tilecache
> >
>
> It would be neat if a BRCK type device could intercept requests to
> tile.openstreetmap.org while an internet connection is working, and then
> serve the same tiles from cache if the internet is down. I'm thinking of
> man-in-the-middle caching on the connection device. Is that a squid-like
> thing to do?  That type of caching may already be a generic function of
> BRCK. It would mean that if you have some tool running locally, but which
> is designed to require an internet connection for embedded maps (hitting
> tile.openstreetmap.org in the standard way) it could carry on working,
> without re-configuring tile URLs.
>
> ...but it wouldn't have all the tiles in the region. Just those which
> somebody had viewed before. To have all the tiles, the temptation is to
> request the full pyramid as a bulk tile download. That causes problems for
> the server, and is strictly disallowed on the main osm tile server, but you
> could imagine some set-up in which aid workers are allowed to bulk-download
> a pyramid of tiles from a HOT tile server before they get on a plane.
>
> Of course the smart way is to run a tile server in the field. Smart
> because it's more compact, and also because feeding in diffs is a reliable
> compact thing to do. Another "solved problem" really ...Except that the
> technology is somehow still far too complicated to give to a random
> non-technical aid worker. In fact I think even people like MapAction didn't
> get their heads around it. Rendering is still very much an OpenStreetMap
> expert skill.
>
> It think tiled vector data will be the key to lowering barriers here. You
> mentioned tiles and API data as two forms of caching, but cached *vector*
> data has huge potential. This is a bit more of a blue skies idea. But check
> out this tantalising preview from the MapBox guys: https://vine.co/v/b0DvTPnpPtw
> That's the whole planet on USB key, rendering on the fly.  I think we want
> to get to the point where aid workers don't leave home without a copy of
> this. Then another challenge is allowing them to request low-bandwidth data
> updates when they have internet. Of course there are some pretty amazing
> mobile apps which use a tile vector data approach. I really love
> MapsWithMe, but it's closed-source and doesn't do low-bandwidth updates. Is
> AND the best open source one? I hope we'll see convergence on an open
> standard and open tools to view, and update vector tiles. What's the best
> way for HOT to push things in that direction?
>
> Harry Wood
>
>
>
>
>
>
>  A disadvantage is that they only cache what has been requested.
>
>
>
> I think a remote team with sporadic internet connection.
>
>
> on the topic of HOT usb stick.... https://vine.co/v/b0DvTPnpPtw <<< The
> entire word rendering on the fly!
>
>
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