[Xastir-dev] [Xastir] Open Street Map support (read this)

[Jerry Dunmire]

Hi Curt,
I moved this to the dev list.

I think I understand the issues people are having and they all appear
to happen on the transition to/from OSM levels. There is also an area
select issue, but I'm pretty sure that is a minor issue, probably an
off-by-one type of thing.

I spent well into late last night (this morning) trying to find the
right place to put in the transition from continuous scaling to levels
but I'm not quite there. I know what needs to be done but I'm still
learning the code and looking for a single place that covers all the
transitions.

I started to look at scaling the bit maps, but that will require still
another learning curve and would still need to learn the flow of the
program. So I don't feel like I'm wasting time fixing the transition
problem, nor do I think it will slow down the alternate scaling.

I would also like to propose, to be implemented at the same time as
the scaling change, a user option to use either the OSM levels or the
linear scaling. My reasoning is that scaling bit maps generally
produces blocky and/or blurry images. My personal preference is to
trade off better looking maps for less flexibility in setting the
scale, but I understand that others will have a different preference
and I think I can accommodate both.

I also want to get to the point where we can cache and use the OSM
tiles rather than large bitmaps. A slippy map implementation would be
great, but probably beyond my present skills. The use of tile caching
should provide a faster interface and eliminate large downloads for
small position changes.

I have to travel for a couple of days starting tomorrow afternoon. So
my goal, assuming you are not adamant that I not do it, is to fix the
transition error before I leave. Then I can get started on the linear
scaling when I get back.

Will that be OK?

...jerry


On Thu, Jun 10, 2010 at 8:45 AM, Curt, WE7U <curt.we7u at gmail.com> wrote:
> On Wed, 9 Jun 2010, Jerry Dunmire wrote:
>
>> Thanks Tom for the analysis. I'll look into where else calling the
>> adj_to_OSM_levels()
>> needs to be called as a short term fix until I can figure out (really
>> just learn what's already there) a better scaling method.
>
> Considering the types of issues people are having, I'd urge you do
> concentrate instead on learning how the other map modules do their
> scaling, then fix up the OSM module.  A better use of your time.
>
> If we get too ancy before that's complete then we can do the
> short-term fixes ourselves.
>
> --
> Curt, WE7U.                         <http://www.eskimo.com/~archer>
>   APRS:  Where it's at!                    <http://www.xastir.org>
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