Matt, is an ultra hiker who wanted to publish his location for all to see, yet mask some of the details (such as timestamp). His solution, which he describes here, makes use of a clever service: mapalist. Mapalist monitors a Google Spreadsheet and converts the data published there to flags on a map.
Matt's solution for sharing controlled waypoints involves manually editing a Google Doc on his phone and then having Mapalist publish this data. That's certainly a workable solution, but of course, my first thought was: how can I automate this?
The answer: Tasker! What makes this so easy to do is the existence of a Tasker plugin to update Google Spreadsheets. I installed the plugin, signed up with mapalist, and created a skeleton Google Spreadsheet. All that was left to do was to use Tasker to glue everything together.
First, I had to figure out what event I wanted to trigger logging my location. I could have done it based on time of day, which for a multi-day hike, makes quite a bit of sense. Another option: I could have wired this into my Pebble watch, so points are saved whenever I click a button on my watch. For my little test, I hooked it into the Steps Taken event in Tasker.
For testing purposes, I choose 50 as the step interval. In a real hiking scenario, I'd probably set it to five or ten thousand steps, depending on how frequently I wanted the points to be published.
Next, I had to write the actual Tasker action to grab the location, tweak the format a bit and push the data to the Spreadsheet plugin. Here's that code:
Profile: Map My Location Event: Steps Taken [ Number:50 ] Enter: Map My Location A1: Get Location [ Source:GPS ... ] A2: Variable Set [ Name:%data To:%LOC;My Location within %LOCACC meters Do ] A3: Variable Search Replace [ Variable:%data Search:, Replace With:; ] A4: Spreadsheet Update [ Configuration:Update Where was I? Timeout (Seconds):20 ]
I then turned on the event during a walk and logged a few points. You'll notice that the points are sort of all over the place. That's due to the limitation in GPS accuracy and the fact that I was logging points so close together. I'll replace this example with data from my next run or hike, and the map should be more informative. Here's an example of a run I captured and published:
If I were using this data for more than testing purposes, I'd update the above action to also store the data in a text file locally. That way, even if there were internet issues along the trail, I'd know I would have a reliable stash of data regardless.
Update: I've temporarily disabled the map above until I get a better data set.
Update: I've got a real example map above in place, and have published version 2.0 of this solution, which supports offline publishing.