Yaouh! out (update for tangogps maps)

Risto H. Kurppa risto at kurppa.fi
Tue Jan 20 14:06:47 CET 2009

On Tue, Jan 20, 2009 at 2:59 PM, Helge Hafting <helge.hafting at hist.no> wrote:
> Risto H. Kurppa wrote:
>> huh - so Tangogps is able to update tiles?? I didn't know it, lack of
>> reading/documentation/UI/something.
> Just click anywhere on the map. "map download" is the last item on the
> popup menu.

> There seem to be a bug in that the zoom level you're looking at doesn't
> get updated. A user-configurable amount of zoom levels below are
> downloaded though. I therefore tend to zoom one level out before
> downloading.
> I don't know if it uses etags, but I guess it blindly downloads all. If
> it used etags, then it could save space by not having tens of thousands
> of identical copies of "the blank land tile" and "the blank sea tile".
> Helge Hafting

I think you got me wrong: yes, I know that it can download new tiles,
but if you already have downloaded the tiles of some area and then
after some months you'd like to get the latest map tiles (=dowload the
latest, changed tiles), does the 'download tool' do it or does it see
that the tiles are already there and will not download anything.

In some update scripts the etag is used to recognize if the tile on
the server is different than the local tile and if it is, then the
tile file is downloaded.

Or maybe I got you wrong :)

Anyway, a tool to upgrade the tiles (that uses the etag thing, not
downloading all the files) is needed and I think we've seen it now,
just need to test..


| risto h. kurppa
| risto at kurppa dot fi
| http://risto.kurppa.fi

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