Mobile Trail Explorer

Mobile Trail ExplorerExplore your trails using the mobile phone and GPS unit (internal/external)

Mountain Bike Trail

Mobile Trail Explorer is an application where user can view and record tracks using the mobile phone and GPS device (either external or internal). Recorded tracks can be exported in KML or GPX formats so that they can be viewed in Google Earth application. Mobile Trail Explorer is mainly targeted for recording biking, hiking etc. trails.

You can also create trails or placemarks in Google Earth and import those to Mobile Trail Explorer in KML format. You can then display the imported track as “ghost” trail and follow the trail or waypoints.

Mobile Trail Explorer can also post your current location to web in specified URL address. You can send your current location, speed, altitude and heading information in query parameters and do whatever you like with them on your server application.

Mobile Trail Explorer software runs on Java platform (J2ME/Java ME) so it is supported by many mobile phones. It is required that mobile phone supports either Bluetooth connections (JSR 82) or Location API (JSR 179) for GPS and File connection (JSR 75) for exporting trails to kml files.

Platform: Java MIDP-2.0 CLDC-1.1

Price: Free

License: GPL

Screenshots (Nokia N80):

Mobile Trail Explorer - Trail view Mobile Trail Explorer - Elevation view

Mobile Trail Explorer - Information view Mobile Trail Explorer - Waypoints view

Mobile Trail Explorer - Satellites view Mobile Trail Explorer - Satellite sky view

Nokia E71:

Mobile Trail Explorer displaying map from OpenStreetMap
Mobile Trail Explorer displaying map from OpenStreetMap

Trail exported to Google Earth:

Recorded Trail in Google Earth

Download example: track_2006-09-07_08-47.kml


Latest Stable Version:

Latest Beta Version:

Discussion Group:

Google Groups
Subscribe to mobile-trail-explorer

Visit this group

Version History:

Version 1.14 (March 18th 2009)

  • New logo and icon
  • Improved MapCache initialization time
  • Fixed information screen scrolling
  • Splash screen hang fix (Issue 106)
  • WGS84 coordinates in degrees and minutes (Issue 162, Thanks Marco can Eck)
  • Fixed NullPointerException with S40 devices (Issue 145, 164)
  • NoSuchFieldError fixed (Issue 166)
  • Added decimal check to calculate time form (Issue 167)

Version 1.13 (November 15th 2008)

  • Option to prevent Map tiles from being downloaded over the network (Cached tiles will still be displayed)
  • Bug fix: When the locale is changed manually, it will be saved (From Kaspar)
  • Bug fix: LocaleManager does now respect the user-selected locale (From Kaspar)
  • Simplified the addition for additional locales (From Kaspar)
  • Find place by using Google service (From Kaspar)
  • German support tweaks (From Peter)
  • OpenStreetMap surveyor feature (From Vikas)

Version 1.12 (August 13th 2008)

  • New languages: French and Dutch
  • NoSuchFieldError fixed (Issue 123)

Version 1.11 (August 5th 2008)

  • Renamed “Waypoints” to “Places” (Issue 92)
  • Filename uses datestamp with seconds
  • User can add audio-markers
  • Configurable action keys (* and # keys)
  • New speedometer screen (Issue 112)
  • Support different grid formats (Contributed by Kaspar Mösinger)
  • Encoding problems with KML import (Issue 120, Contribution from Bastian)

Version 1.10 (May 6th 2008)

  • Support varying screen sizes like rotating screen on N95 (Issue 90)
  • Improved startup time
  • Support for uploading position to web server (Issue 78)
  • Scrolling (up/down) works on the information screen (Issue 73)
  • Fixed the saving/loading of trails using RMS (Issue 89)
  • Import trails from KML files
  • Import waypoints from KML files
  • Fixed waypoint editing when handling quickly added or imported waypoints

Version 1.9 (April 1st 2008)

  • Trail is now projected using the mercator projection
  • Both trail and map are now zoomed with same keys (1 and 3)
  • File browser for importing trails and selecting export path
  • Logger can now write to the filesystem
  • Signal strength SNR key to Sky View and updated help screen
  • Change screen on space key as well as 0 key
  • Export and import waypoints
  • Initial JSR-179 support

Version 1.8 (December 3rd 2007)

  • Trail duration is displayed and exported to KML
  • Trail maximum speed is displayed and exported to KML
  • Trail average speed is displayed
  • Initial map texture support (Issue 49)
  • User can select filename for exported trail

Version 1.7 (August 17th 2007)

  • Changed Logging Levels to more “understandable” ones.
  • Logger now states what level it’s currently logging at.
  • Changed How Trails & GpsPositions are serialized
  • Implemented a Version system, to allow for updates etc.
  • Implemented an update feature for version 1.6 and lower
  • Implemented re-exporting of Tracks that are saved in RMS (Issue 44)
  • Satellite sky view (Issue 51)
  • Track elevation view (Issue 31)
  • Export saved trail (Issue 45/50)
  • Added Sms Ability to send a GpsPosition/Waypoint as an SMS! (Issue 52)
  • Drawing style options (draw whole the trail or end of the trail)

Version 1.6 (June 10th 2007)

  • Display current time (Issue 37)
  • Fix for invalid KML (Issue 38)
  • Display ghost trail (Issue 33)
  • Altitude is exported to both KML and GPX files (Issue 34)
  • Waypoints are exported to GPX files (Issue 34)

Version 1.5 (April 28th 2007)

  • Autosuggest waypoint name (Issue 12)
  • Added ability to ‘Force’ screen’s backlight to stay on (Issue 21)
  • Improved speed of KmlConverter and GpxConverter
  • MTE now remembers last position on startup (Issue 17)
  • About/Help Screen (Issue 23)
  • Fixed Bluetooth Device List refresh exception (Issue 22)
  • Controls in the setting forms will be re-initialized when pressing “Cancel” (Issue 27)
  • Added zoom scale bar (Issue 28)
  • Separate information, waypoints and satellites view (Issue 15)
  • Fixed “Unable to save waypoints” problem (Issue 26)
  • Added “Trail Actions” screen when stopping recording, where user can export the trail to multiple formats and/or save trail to phone memory (Issue 18)
  • Fixed bluetooth problem seen on Nokia 6230 (Thanks Patrick)

Version 1.4 (March 26th 2007)

  • Compass in main view
  • Fixed the GPX format and file extension
  • Distance is displayed in main view
  • User can pan the view

Version 1.3 (February 25th 2007)

  • Display speed, altitude and heading
  • Record speed/time markers every Nth position
  • Export trails in GPX format

Version 1.2 (January 24th 2007)

  • User can change recording interval via settings
  • Recording is automatically paused when user is stopped
  • Waypoints are stored when application shuts down

Version 0.2 (October 7th 2006)

  • First “public” release
  • Record and export trails to Google Earth’s KML format
  • Draw recorded trail and waypoints
  • Show current location as longitude and latitude
  • Tommi Laukkanen

    Thanks Jimmy! I have already added the feature on recording “markers” every Nth recorded position that will include the speed and time information. I could also add the start and stop icons so that user could easily see the starting and ending point from Google Earth. I’ll try to release the next version within a week.

    Nice idea to use the application to store speed cameras as waypoints :)

  • Mario S.

    I have also an additional feature idea for next releases.
    It would be great if Trail Explorer shows the current length of the track below the speed info. Because on mountain bike trips I want to know how far I have been cycling. Perhaps you could also write the total length of track in the Endpoint Placemark in a kind of info box and also the average speed and the total time for this track.

    You could calculate the distance between two recording points with these formulas:

  • Tommi Laukkanen

    I’ll add this to a upcoming feature list. I think that distance could be also shown in the trail markers for every Nth recorded position.

    Thanks for the formula link. No need to reinvent the wheel :)

  • Dakota Reese

    Wow. I love the new build. I was thinking about adding Dilution of Precision check (to eliminate extremely bad GPS guess), but was unsure on how to best add multiple sentence parsing to your code. It looks like it is a quick add with your new parser.

    Thanks again for a great program.

  • Martin Tilma

    Hi, I donwloaded version 1.3 on my Sony Ericsson W800i. After a few track points the I get: “Last refresh xx seconds” and it wont track any points.

    I user a ADAPT AD-300 Bluetooth GPS Receiver.

    What can I do?

  • Tommi Laukkanen

    Hi Martin! If you are able to record few track points then it should work. It sounds like the phone lost the connection to GPS receiver or GPS receiver lost track of satellites. Does it work with other GPS software, like GMaps?

  • Richard Proud

    Hi Martin

    The application installs fine and connects to my bluetooth GPS OK and I can start recording. However, when I stop recording I get a java error to do with file writing: java.lang.Exception: writeToFile: Open Connector: java.lang.illegalArgumentException. Any ideas? I have not specified a destination folder into the Export box under Settings as I assume it will just write the trial file locally to the application. I’m using it on a SonyEricsson V600i.

    Many thanks

  • Tommi Laukkanen

    Hi Richard! Mobile Trail Explorer doesn’t store trails locally into MIDlet’s record store. It saves them always using the File Connection API so you should specify the destination folder for your exports. Default E:/ seems to work well with majority of phones.

  • Martin Tilma

    Hi Tommi, I tested with Gmap (for a short period, I don’t have flat fee internet) and it is working. Do you know other applications that don’t need an internet connection?

    Is there a way to let your application check if there is a good connection with the GPS device?

  • Richard Proud

    Hi Tommi

    E:/ points to a memory card I believe? The phone I’m using doesn’t have one, so how would I reference the Applications folder as the place to write the track out? Would it be C:/Applications? I’m not sure how phone disks are organised / referenced.

    I have tried it on another phone (Nokia), where file writing to E:/ is not a problem as it has a memory card. However, after about 20 seconds of recording, it seems to loose the GPS stream and goes into refresh mode. Any ideas on that issue too?

    It’s a great application and does exactly what I need, but I’m just struggling to get it setup OK on either of the phones I have.

    Many thanks

  • Martin Tilma

    Hello Tommi, I tryied a different GPS BT device and now its working okay. But its not my own GPS device.

    My own device starts flashing the bluetooth led and then losses connection or something.

    When I stop recording and start recording the connection with my bluetooth GPS is restored (for a while)

    any thoughts?

  • Tommi Laukkanen

    Hi Richard and Martin! The path is phone specific and E:/ seems to work well with Symbian phones. Unfortunately I haven’t included a file browser into a Mobile Trail Explorer so you can’t browse for valid directory.

    But fortunately I was able to code a small browser Midlet that scans your phones root drives and displays them in a simple text box. You can use this app to determine a valid path to be used with Mobile Trail Explorer. You can download this small app here:

    I hope that this helps for your problems.

    The 20 sec problem seems to be more phone or GPS unit specific. My Nokia N80 had a firmware bug that caused long running bluetooth connections to brake down after a few minutes and only firmware update was able to fix this. If Mobile Trail Explorer is able to start the recording then it should be able to continue to do so as long as user stops it (or bluetooth connection brakes down).

    Some GPS units can have problems connecting to satellites. I’ve had a GPS device that needed reset by removing a battery before it could connect to satellites properly.

  • Richard Proud

    Thanks Tommi – much appreciated. I’ll give the utility a go.

  • orgoz


    Thanks for this great utility under GPL license ! It will be useful for me to map my city (for the OpenStreetMap project).

    It works good on a Nokia N70 and an Evermore BT920 GPS receiver :-)

    Thanks again !
    Best regards

  • Martin Tilma

    Hello Tommi, I did a firmware upgrade on my phone. But doesn’t solve the problem for me. After a while (less then 2 minutes) the bluetooth connection brakes down.

    I hope there is some solution…

  • Tommi Laukkanen

    Hi Martin, I found few articles that says the problem is on the phone hardware (W800i) and can’t be fixed with the firmware update.

    Here is one comment of W800i bluetooth dropouts

    I hope this helps.

  • Urban Öhman

    Excellent work! However, after my first day out with a SE K750i and a “navibe” bluetooth GPS I find that the BT connection is broken ever so often. This means that the connection is not maintained longer than 60 seconds, 10-15 seconds is more common. Any other out there who has experienced this behaviour?

    I have a feeling that it correlates with the energy-saving scheme of the Sony-Ericsson phone (the screen goes black), but I am not sure.

    Hooked up against a Palm the navigator has no problems whatsoever.

  • Paul

    Hi Tommi,

    Thanks for this excellent app, I am using it with:

    Nokia N80 (58.01)
    V 4.0623.042

    Nokia LD-3W Bluetooth GPS

    I have a question, I find that the app only outputs .kml files, regardless of my choice in settings.

    When I put the .kml file generated when selecting .gpx in the menu, into Google Earth I get the following error:

    – Open of file “*.kml” failed: File has missing or bad root element. –

    Do you have any ideas?

    Many thanks, Paul

  • Tommi Laukkanen

    Hi Paul!

    Thanks for reporting the used devices. I’m using the same hardware as you although my firmware is few months older then your’s.

    The GPX extension has been fixed in the current development version. When you select GPX format the current release version writes the file content as GPX but still uses .kml file extension. Next release will use .gpx file extension.

  • Dave H

    Hello, I’m new to the forum… this interested me because I noticed the comment someone had about the Samsung D807… I have the same issue.

    I’ve had to become literate at Java MIDlet programming to write a script to help determine the problem.

    It is the line of code that asks to find local devices that “hangs” this phone. [ getlocaldevice() ] However, it might be a security issue (bug) with the firmware… I suspect the phone *should* have a pop-up asking if you OK this app to connect to the local device, but that’s not happening. I still have some toying around to do in an attempt to further figure this out… but I suspect a Firmware issue.

    Has anyone else been working on this? I like this phone, but this could be a deal breaker.


  • Tommi Laukkanen

    Hi Dave! I haven’t received any information that anyone would have been working on this issue. I think that all D807 owners would be happy any progress that you might have on this issue.

  • Tommi Laukkanen

    This blog entry is starting to fill up on your excellent comments but the blog page wasn’t meant to be this large ( I’ve have to pay for the traffic :) ). So now I have created an user group in the Google Groups where discussion can be continued with real discussion forum tools. Please write your future entries in the Google Group Discussion list:

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