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Couple Litchi questions....

Discussion in 'Phantom 2 Vision + Discussion' started by Frogbone, Jul 15, 2015.

  1. Frogbone

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    - Maps

    How does Litchi get the maps? I think I read somewhere that you can connect to internet at the current place and it will download the local map.
    What if I don't have internet there? How do I preload maps? How large of an area can I preload?
    I will be doing an Ireland road trip and I will be in a lot of remote areas. If there was a way to load the entire island that would be great as I don't think I will be able to get maps in remote areas. Also, with preloaded maps I can plan missions ahead of time.

    - POI mission
    I did one yesterday and it appeared that after it completed it's circle it proceeded to do the same circle again. Is this the way it is designed? Run mission until I manually stop it ?
    How do I cancel a POI mission (or any other mission) while it is in progress? I saw the "Home" button but I don't want to stop and have to go back home every time. In my case I flicked S1 and I was able to manually continue to fly. However, the display still showed the "return to Home" message until I exited out of Litchi and restarted it. It seemed that when the RTH was triggered it wanted to stay active until it was actually at home.
     
  2. tcope

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    You load the app when you do have a connection and scroll to the area you will be flying in. I'm also _pretty_ sure you can use Google Maps to download the map from that area and then this loads in the flying app. I'm not 100 percent sure about this but I think it works.
     
  3. Frogbone

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    I might be in several areas on a particular day where I won't have internet from early morning to late night.
    If the area I can select in the morning is big enough to cover all the spots I am travelling to then this would work. However, if there is a limitation of how large of a map it saves that might cause a problem.

    I know google maps lets you save maps but only up to a certain size. I will have to check that out.
     
  4. RoyVa

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    You have to cache the Google maps if you don't have internet where you are going to fly. When you have Internet open google maps and go to the location you are going to fly at. Move the maps around so you have all the area you will be flying in. Then it caches those. Close the app then reopen when you are at that location and the map should open with GPS working.
     
  5. MapMaker53

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    Well, this is how I generally do it, though others may have a better method.

    While connected to a local wifi internet connection (either at home -- or at a local library, Starbucks, Panera Bread restaurant, hotel, etc. if out of town), open Litchi and tap the FPV icon in the upper left and choose the GS option. A map/satellite image of your present location should load. Pinch the image smaller and pan to the location you wish to fly. Then enlarge again to see the general flying area.

    Plot a GS mission by tapping waypoints with your finger onto the satellite image, adjust each waypoint setting by tapping or holding down the waypoint to slide and adjust it's location.

    Save the mission by taping the button on the left that has the down arrow and assigning the mission a name.

    If going immediately out to fly, DO NOT TURN OFF YOUR TABLET (I believe turning off the tablet clears the cache memory) as doing so will loose the map/satellite image once you loose your wifi internet connection. You CAN close the Litchi app if you like, but do not turn off the tablet. Simply put it into standby mode with a simple tap of your tablet's on/off switch. It takes a long time to loose battery power while in standby mode. Drive to the location you wish to fly, tap your tablet on/off switch to wake it up, start the Litchi app (if you had closed it), and call up the GS mission. The satellite image should also show up with it even though you have no wifi internet connection.

    If not going immediately out to fly because your flying location is really far away -- like in a different state -- you can turn your tablet totally off after saving a mission, but you will have to use an out of town free wifi internet source as mentioned above to load the mission (previously created at home) and have the map/satellite image show up with it. At that point, again, do not turn off your tablet but simply tap the on/off button and put it into standby/sleep mode. Tap it again when you are at your flying location.

    If others do the caching a better way, I'm all ears.
    Thanks.

    NOTE: You can test this method by creating a mission while on your home wifi (just a real simple mission with 2 waypoints), save the mission, and then turn your tablet wifi connection off. Close out the Litchi and put your tablet into standby mode. Take your tablet out of standby mode. Remember, you now do not have a wifi connection because you had turned the tablet wifi connection off. Open Litchi, load the GS mission, and the satellite image should still appear. Understand that if you have a different mission saved that uses a different satellite image, you will not be able to load that second satellite image until again reconnected to wifi for caching.

    Also, someone in the Google Groups Litchi forum suggested you can use your cell phone as a wifi hotspot and connect to it first to call up the map in Litchi, then connect to the Phantom -- but I've never done that because I don't own a smart phone with internet access.

    One more tip.. I flew a huge site last week during the course of an 8 hour day with no internet connection, but had previously cached the satellite image of the site. Whenever I was driving between locations, I put the tablet into sleep mode and helped replenish its charge by plugging it into my accessory outlet with a USB adapter.

    Sorry.... Just another observation on my part... It seems you have to do the above procedure for each POV app you may want to use. I discovered that my cached satellite image in Litchi did not show up in the Ultimate Flight app when I wanted to switch over to that app for a particular flight that day.
     
    #5 MapMaker53, Jul 15, 2015
    Last edited: Jul 15, 2015
  6. Frogbone

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    Even caching google maps only lets me save a small area and only so many places. It seems very impractical.
    On my phone I have the Samsung "Here" app. I can download entire states.
    I wonder if they would maybe work with Litchi ?
     
  7. Frogbone

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    I might have found my solution and here is what I did:

    I turned on Developer options on my Nexus 7
    Enabled "Mock Locations"
    Installed "My Fake GPS Location"

    While connected to the Internet at home in the US I opened the fake location app and searched for "Blarney Castle". App took me there and I set my current location right there.
    Opened Litchi, hit the "locate" button and voila...it took me right over Blarney Castle with a fairly decent size of satellite maps around it.

    Turned off wifi, turned off Litchi
    Turned Litchi back on and sure enough it kept the map.

    Turned tablet off and rebooted, mind you after reboot wifi is still off
    Started the fake GPS app which still had my last setting saved.
    Opened litchi and again, the maps where there

    EUREKA !!!

    Then I thought, hey, can I do this with more locations? Tried it with Rock of Cashel and Cliffs of Moher.
    Same sequence as above.

    Guess what? All three were there :)

    So, even though I might not have Internet when I am out there during the day, anything previously saved remains on the tablet. Once I have everything plotted with the Fake GPS App I won't need to run that map anymore as my Tablet GPS will report my true location.

    I am just not sure how long Litchi will keep my maps stored, maybe the developer will see this thread and chimes in. Power cycling my tablet didn't get rid of my cached apps so theoretically they should stay for good unless there's only so much memory allocated for that and eventually stuff gets overwritten ?
     
  8. Kaehn

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    Litchi uses the Google Maps API in order to display maps. Google's API manages how and when the maps are saved entirely and unfortunately for us they don't make this very clear in the documentation.

    What I do know (and to confirm what's been said above):
    - you cannot cache maps in another application (such as Google maps), they will not load in Litchi
    - restarting the mobile device has high chances of clearing the cache so best not to do it, you can however close Litchi

    Generally there are 2 ways to cache maps:

    - If you have 3G/LTE at the flying location, then you can simply start the app there, if the app auto connects to the phantom fine, just hit the main top button to disconnect (which will disable wifi for you too, leaving you with the LTE/3G connection), then simply move the map around to ensure the map tiles are saved.

    - If you do not have internet at the flying location, you will need to pre-cache maps either at home or anywhere you can find an internet connection. Start the app, then move the map around where you intend to fly.

    I do not know how many map tiles can be cached nor do I know how long they are cached for, as I said above Google doesn't make this part of the API very clear.

    @Frogbone I am not sure what that fake GPS app does, but that sounds weird, I'm not sure how faking the location could have an effect on the Litchi map tiles cache, considering it's not a shared cache.
     
    #8 Kaehn, Jul 16, 2015
    Last edited: Jul 16, 2015
  9. Frogbone

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    Thanks for the clarification !!

    My thinking for faking the location was to see what Litchi does when the device reports a current location to the app when connected to the Internet.
    My observation was that Litchi loads the map for the current GPS location provided to it by the Android system.

    My further thinking was then to use the Fake GPS Location to mimic "having Internet" there when I know that I won't have it when I am actually there.

    So,
    - I told Litchi by this way that I am at point X through the fake GPS app.
    - Litchi uses my current Internet connection to "cache" the local map
    - I then changed my location through the fake GPS app
    - Litchi "followed" me to that location and again "cached" the map there
    - I turned off my Internet connection
    - Turned off tablet
    - Rebooted
    - Went back to first location with fake GPS app
    - Started Litchi
    - Litchi displayed the map previously "cached"
    - Went to second location again through fake GPS map
    -Litchi again displayed correct map

    This told me that once Litchi has Internet at any given location it "caches" that map and stores it somewhere. That map does not get lost even when shutting off the tablet.
    How long the map is retained and how many location it will save and retain is the big question.
    I have no idea how the app works and does all this but I thought you might have some answers as you are the developer
     
    kelleysislander likes this.