[drats_users] Map Downloader Question

[Dave Cooley]

Okay I was interpreting the interface incorrectly. The max zoom thing messed
me up. If I select the 120 mile radius, it will draw a circle (with square
edges due to the map tiles being square) 240 miles across centered on the
coordinates I input. Is this correct? 

The we click start and come back in an hour.
I assume map tiles of water should take less time to download (unless we are
now plotting the favorite fishing holes) so it may not be that bad. 

In that Florida and Texas represent non-rectilinear (cool word by the way)
geographic challeneges, I am sure that we can adapt to the thinking of the
rest...

P.S. now that we are on the subject when are you going to add aerial views
and weather to the realtime map overlays. I couldn't resist.........

Happy Holidays to all

Dave Cooley
N4DIB



-----Original Message-----
From: drats_users-bounces at lists.danplanet.com
[mailto:drats_users-bounces at lists.danplanet.com] On Behalf Of Dan Smith
Sent: Friday, December 19, 2008 4:32 PM
To: Discussion of D-RATS
Subject: Re: [drats_users] Map Downloader Question


> 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
_______________________________________________
drats_users mailing list
drats_users at lists.danplanet.com
http://lists.danplanet.com/mailman/listinfo/drats_users

Internal Virus Database is out of date.
Checked by AVG - http://www.avg.com 
Version: 8.0.173 / Virus Database: 270.8.0/1717 - Release Date: 10/9/2008
4:56 PM