[Xastir] Announcing tile support for OSM

[Curt, WE7U]

On Wed, 28 Jul 2010, James Cameron wrote:

> Are the http requests streamed in one connection, or are there multiple
> connections?  Are the multiple connections fired simultaneously or are
> they queued one by one?
>
> The reason I ask is that several users are on high latency connections,
> such as satellite or commercial wireless "broadband", and a tiling
> implementation that makes multiple requests pays the latency penalty
> many times.

The requests are lined up serially, plus you can interrupt between
them with a pan or zoom or F4.  F4 gives you the optimum zoom level
in Xastir to match the tile resolution that's nearest.  I believe
Jerry mentioned that the OSM servers will only accept 2 connections
at a time from one address anyway, so you can't do much in the way
of parallel operation to begin with.

In any case, once you have an initial set of tiles to match your
desktop, panning only requests a few tiles along the new edge.  For
zooming you take a hit, but only the first time.  It gets faster as
it "learns" the area you move around in (because of caching the
tiles).

-- 
Curt, WE7U.                         <http://www.eskimo.com/~archer>
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