[drats_users] Map Downloader Question

[Dan Smith]

> If I understand the downloader correctly, it works from a radius
> around the given lat/lon points.  The higher resolution you select
> the smaller the radius.

No, not quite.  The larger the radius, the lower the starting zoom level
is used.  However, no matter what radius you choose, it always goes down
to street level.

So, if you choose a diameter of 15 miles, then it will get everything at
zoom levels 13-17 around your center.  If you choose the 60 mile
diameter, then it will get zoom levels 11-17 around your center.

In short, the diameter you choose only affects how far *out* you can
zoom from your center.

> With the old downloader you could specify a custom area (not a
> circle) and what level you wanted to drill down to. This is extremely
> helpful for those of us who want to download an area of interest
> other than a perfect circle like a strip along the coast of Florida.

Your state is just poorly shaped, that's all :)

> It also allows us to define a specific area (i.e. county boundaries)
> for areas of interest.  For most ARES and RACES groups I would think
> that the area of concern would be an entire county and street level
> detail. The current downloader doesn't posses this capability.

I think it does.  Are you trying something and experiencing a problem,
or are you making an assumption based on the interface?

> If the new downloader could be designed to enter boundaries  (i.e.
> n,s,e & w) along with the desired level, that would take care of it.

The way the data is available from the map source, this is harder than
it sounds, and significantly more complex, which is why the older design
didn't work very well.

I should also point out that the new one doesn't download a circle, it
downloads a square.  The way the data is arranged, each (square) map
tile at zoom level X is the same area as four tiles at zoom level X+1.
This makes drilling down from a maximum zoom level a very easy calculation.

So, given the above information, and assuming you're not seeing a bug
which is causing it to behave other than intended, is there a problem?
I know that for regions like Florida, you'd have to choose a
significantly larger chunk of map than is really necessary to get the
whole state in one go, but I think that for the rest of us in
rectilinear locales, choosing a center and a maximum zoom is more
straightforward.

I hear more praise of the new approach over the old, which makes me
assume it's more useful that way.

Does anyone else feel strongly one way or the other?  I'd hate to burn a
couple of Saturdays moving it back to the old and more complex model
just because some weirdo from a long-and-skinny state wanted it that
way... :P

> P.S. b11 mail running fine all day. The gremlins have been exorcized!

Good to hear!  Keep pounding.. I'm extra paranoid now :)

-- 
Dan Smith
dsmith#danplanet.com, s/#/@/
www.danplanet.com
KK7DS