Thread: [Announce] modRana: a flexible GPS navigation system
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MartinK is offline MartinK
2013-05-09 , 22:06
Posts: 1,548 | Thanked: 7,510 times | Joined on Apr 2010 @ Czech Republic
#1376
Originally Posted by magic_doc View Post
Hi MartinK,

thanks again for your great work and congratulations for the android-version.
Thanks !

Originally Posted by magic_doc View Post
May I dare to ask if there is any chance to get the messed-up gpx-tracks displayed correctly in the future?

CU Michael
Good point, I really should finally fix that. Hopefully it shouldn't be that difficult (basically just recognize where the segments start/end and start/stop drawing them accordingly).

Originally Posted by malfunctioning View Post
I've done my first experiments and I'm very impressed! I'm using modRana 0.41.1(GTK version).

A couple of questions:

....

- When I am setting up the batch download of tiles, I clicked to calculate the size. When it calculates the size, it looks like it keeps calculating the full size (I suppose it downloads and deletes every single tile?) It would be better probably to just estimate by downloading a representative number of random tiles and then extrapolating (sorry if that's the way it already works, I might have not waited enough).
It is a bit more efficient than downloading the tiles - it downloads just the headers and checks the size field. It does really check all files though - which is not much usable for very large sets. BTW, if it also finds some that some tiles are available from local storage, it removes them from the batch.

Anyway, I like your random sample idea - that could really work quite nicely in most cases ! Picking say 1000 tiles at random and extrapolating from there.

Originally Posted by malfunctioning View Post
- Another comment regarding the last point: When it is calculating the size, if you click back to exit the menu, the application becomes nonresponsive and needs to be closed. I guess the threads that are downloading / calculating the size of the tiles are still running.
Thats weird, I'll check it out. The threads should be daemonic, so that when their parent quits, they should be automatically killed.

Originally Posted by malfunctioning View Post
Great program! I think I'm going to use it for the first time tomorrow.
Thanks & good luck on your travels !

Originally Posted by malfunctioning View Post
Talking of which, does Google really disable batch downloading of tiles? Because that sucks. Anybody knows how to get around that?

Martin, I just had a cool idea: Since Google disables batch download, but downloading tiles in normal use is allowed, wouldn't there be a way to simulate a route that would cover all the target tiles? Unfortunately I suppose you would have to run the route as many times as the zoom levels you have selected, and change zoom level at each pass. And, the route would probably be huge and hard to compute. A strange benefit is that this would take less space, because it wouldn't download tiles that you wouldn't see during normal use (tiles for places unaccessible within the view distance for the range of zooms selected). Also, you might have to be observant of the speed at which the route is run.
I think the algorithm Google uses for baning is much more simple - probably just user-agent & number of tiles downloaded per second. Also, the Google Maps web interface seems to download tile sequentially/in order, so they might also try to detect that.

There are some improvements I plan to eventually implement for batch tile download, that all have legitimate uses, but might be useful for users wanting to work with Google tiles:
  • custom user agent support
    As a good behaving application, modRana correctly reports it's user agent as:
    Code:
    "modRana flexible GPS navigation system (compatible; Linux)"
    Some enterprising users might want to set it to something like:
    Code:
    Mozilla/5.0 (compatible; MSIE 5.5; Linux)
    If anyone wants to experiment with the user agent already in hte current modRana version, it is set in
    Code:
    /opt/modrana/core/configs.py
    on line 190.
    Note that you need to be root to edit this file.
  • limiting the number of tile download threads
  • custom/Random delay between tile downloads
  • support for tileserver mirrors
    Most big tileservers, including the Google ones have 3 or more mirrors. This is mainly due to some Javascript threading limitation, but using multiple mirrors from modRana might be handy.

BTW, modRana supports downloading tiles around a tracklog or current route.

Originally Posted by malfunctioning View Post
I've run into a little problem. I grabbed the car routing data for the US West region directly from http://modrana.org/data/monav/north-...est_car.tar.gz

Then, I stored the resulting folder (us-west) into the path specified in the wiki, and the data files end up in:: /home/user/MyDocs/.maps/monav_data/us-west/routing_car/

But I can see no preferred pack when I try to add it in the modRana Navigation > Routing data options.
Looks like a regression - I'm having the same issue. I've done some changes in how the path to the routing data folder is "computed", which might have triggered it. Hopefully should be an easy fix. BTW, thanks for reporting this!
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