Re: Balloon chasing program [1 Attachment]


James Ewen VE6SRV
 

On Mon, Jul 10, 2017 at 2:25 PM, Jerry Gable jerrygable@yahoo.com
[GPSL] <GPSL-noreply@yahoogroups.com> wrote:

Google doesn't allow their maps to be cached so the plan is OpenStreetMaps or one of the derivatives.
The current implementation does the caching. I still have to figure out the best way to do the cache pre-load.
A typical landing zone can easily be 5+ GB of maps.
A typical landing zone can easliy be kept under a couple dozen MB of
map if you don't grab map tiles that show each sidewalk block. There's
no real need to go past zoom level 14. Most areas won't give you much
detail beyond that. If you're trying to use the map to stay on the
proper side of the road you better look out the window because the
accuracy of the map isn't going to be good enough to keep you from
driving into oncoming traffic. Zoom level 19 is ridiculous to drag in.

Flooding all of those requests can quickly piss off a map supplier.
Bingo! Don't try to grab every tile everywhere. If you really need
that, build your own tile server and render your own tiles.

Will have to figure out a way to mark off the area and then parse out the map requests
over some time.
Pull in the tiles as the user looks at the area. Grab tiles for the
level being viewed and a level or two below. That's not a lot of tiles
to grab, and doesn't put a huge load on the tile server. Keep those
tiles on the HD for offline viewing. Oh yeah, use the standard file
storage method so that other programs using the tiles can share rather
than having to use unique repositories.

Look at aprsisce/32. Lynn Deffenbaugh has been using the OSM and other
tiles for a lot of years now. You can even get topographic tile sets
if you like.

http://aprsisce.wikidot.com/start

http://aprsisce.wikidot.com/tile-sets

With aprsisce/32, you can simply scroll around the map, and it will
pull in tiles for the area you have looked at automatically.

I can scroll around Alberta and grab all tiles down to Z14 in about
20-30 minutes. (350 miles X 750 miles)

BTW, I am interested in your program as well.

I do all that you have on your screen currently with APRSISCE/32 for
the APRS mapping, and my AvMap G6. The AvMap puts 3 user selected
parameters on screen on the GPS, and will center on the targeted
callsign. I usually have altitude, course and speed of the balloon on
screen there. I put the decoded packets on the screen of the D710. The
computer can show the map, track of the balloon, others chasing. etc.
You can put aliases on the station if you like.

I can't get vertical rate on screen though. We send that via status
text from the payload though so you can see it. Time to landing is
interesting. Obviously hard to calculate until after burst.

A vertical altitude graph would be nice to see, so you can observe the
height over time.

James
VE6SRV

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