[Xastir] Script to cache some maps

[Fred Hillhouse Jr]

5/5/5 will produce the same results for most "slippy" tile schemes.

The lat/long bounds are typically the same. But as usual, there are a few
that play differently. If you look at the tiles from flightaware, the tiles
are 600x600 rather than 256x256. For OrdanceSurvey, the tiles are 250x250.
There are a few others that use 256x256 but the bounds are unique. The odd
ducks really don't add anything of value except OS tiles.

While some follow the same scheme (OSM, Google(old), Mapquest), others do
thing like swap X & Y (ArcGIS). Others will do a notY (nautical,
aeronautical). For notY, the math is 2^Z-Y=notY.

Some of the tiles I've played with are, nautical and aeronautical and
satellite imagery. I think nautical charts are available in other forms,
(maybe even usable in Xastir). I only found aeronautical in tiles. It is
interesting to follow a commercial airplane on the high IRF charts while
tracking an APRS user.

Some tiles are PNG and others are JPG.

I normally use OSM, Topo, imagery, and nautical. I like OSM because I can
add details but it lacks in terrain details such as contours. Overall, OSM
is improving. Topo tiles are usually old data but the terrain (contours)
really hasn't changed much over the years and besides, I grew up on 15 and
7.5' maps. When the big one hits we will need new topos for the west coast
and my new Arizona coastline. Imagery is pretty good but tile memory size is
usually bigger and also kind of pointless for anything other than a large
zoom level so the collection stays small. With nautical, I follow N1ZZZ and
KE5KTU (north eastern seaboard, NY to ME) when they're active.



Best regards,
Fred N7FMH




-----Original Message-----
From: xastir-bounces at lists.xastir.org
[mailto:xastir-bounces at lists.xastir.org] On Behalf Of Skyler Fennell
Sent: Thursday, November 19, 2015 5:05 PM
To: Xastir - APRS client software discussion
Subject: Re: [Xastir] Script to cache some maps

Is the tiling system with the zoom/x/y.png standard for non OSM like the
ArcGIS topo?

Does this system work cross between maps, ex. Does 5/5/5.png have the same
lat long bounds between any tile map?

Kd0whb

> On Nov 19, 2015, at 10:50 AM, Fred Hillhouse Jr <fmhillhouse at comcast.net>
wrote:
> 
> I run Windows and use APRSIS32 and I use more than the OSM tiles (e.g.,
> ArcGIS Topo).
> 
> I have used an USB hard drive for tile storage while mobile. You can get
> really big ones for lower cost these days. Some might argue an SSD makes
> more since. I am leery of that since I have had several USB Flash Drive,
> plus, they are costly.
> 
> If you are rendering your own tiles, then plug in a portable hard drive
and
> copy (backup) the latest tile revisions to the portable hard drive.
> 
> Most of the time, space is not all that important. I have less than 10GB
of
> tiles and I do look around the world when something interesting is
> happening. I am in between projects looking to roll out my newest
> configuration.
> 
> I wrote an application to download the tiles I need. I started first with
> something that simply used a GPX file as the source. I haven't finished a
> routine to fetch tiles within a polygon. That would be useful for
counties,
> cities, etc. A whole state would be extreme.
> 
> I don't know if Xastir can actually use tiles but it seems like a logical
> extension if not.
> 
> Best regards,
> Fred N7FMH
> 
> 
> 
> -----Original Message-----
> From: xastir-bounces at lists.xastir.org
> [mailto:xastir-bounces at lists.xastir.org] On Behalf Of Jason KG4WSV
> Sent: Thursday, November 19, 2015 7:42 AM
> To: Xastir - APRS client software discussion
> Subject: Re: [Xastir] Script to cache some maps
> 
>> On Wed, Nov 18, 2015 at 10:23 PM, Skyler F <electricity440 at gmail.com>
wrote:
>> 
>> So the ultimate solution for the raspberry pi folks would be to run a
tile
>> server on their home computer (so there is no violation of terms and you
>> can download as many tiles as needed), and then run this script to cache
> as
>> many maps as needed onto their pi. I think that is the way to go!
> 
> This sorta sounds like the worst of both worlds to me - you are still tied
> to your home network connectivity to get maps, but you additionally have
> all of the hassles of running a server just to keep maps available.  ugh.
> 
> I'm with Andrew, my "ultimate" is vector data that xastir can ingest
> directly.
> 
> The only reason for me to set up a map server is if I can't get said
vector
> data formatted for xastir.  There's a slight advantage to sourcing OSM
> data, since that's the FOSS GIS data du jour.  A portable tile server
(e.g.
> mobile, incident command post, remote event HQ, etc) would likely require
a
> fairly well endowed computer (high end laptop, potent SBC like an Intel
> NUC, or _maybe_ a higher end ARM like a Jetson TK1).  I seriously doubt
> Pi/beaglebone/etc is going to get the job done as a tile server, they're
> just too anemic computationally.
> 
> -Jason
> kg4wsv
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