Home > Cartography, OpenStreetMap, Uncategorized > POSM, OSM without the Internet

POSM, OSM without the Internet


Disclaimer: I am in no way affiliated with the POSM or its development.  I’m just an OSM contributor who thought this was neat and wanted to share the love.

For a while I’ve been envisioning some sort of system that would allow map data to be collected over a large area and then committed and later shared without an Internet connection.  Going into a rural area without sufficient or existing Internet connectivity would surely be a problem with using tools for compiling and rendering OpenStreetMap (OSM) data.  I had come up with a few solutions that were not unique and seems to have been tried before.

Sneakernet

Yep, just toss your GPS tracks, pictures, and JOSM output onto a USB thumb drive and walk/drive it over to a centralized location, where Internet connectivity is available, for processing.  Sure, it might take a while to collect all the information and take a while longer to redistribute all the information to the people in the field but it works.

Intranet

Okay, being a network geek this is my favorite solution; build your own network!  For the record, I’m not talking about stringing wire from village to village like soldiers did around Europe in WWII.  No, I’m talking about building wireless MANs to connect wired/wireless LANs that may already exist in these villages (or we can build our own!).

Adding our own infrastructure (email, web, and other servers) to the network would provide basic communications between villages with a potential connection to the Internet from a faraway town.

But this is far from fun for a software geek (I’m not one of those).  From here enter the POSM.

POSM

The Portable OpenStreetMap, or POSM, device is a small server that hosts all the tools needed to compile, edit, and publish collected mapping data without Internet connectivity.  The project was discussed at the US State of the Map (2016) and the video is a must-watch.

Of course a POSM could be added to either a Sneakernet or Intranet to allow for distributed data to be collected faster but the POSM, alone, seems to make working with this data much easier in the field.

Back to my thoughts

Honestly, my first thoughts around making a box like this, even before I heard about POSM, was the syncing of data back to the master OSM database.  If you watched the video to the end it appears someone else in the crowd had the same concern.  The answer to this was the use of git to manage conflicts.  To me this is very smart as git was made for this type of use-case (distributed data that needs to be compiled together at a core location).

I do wonder how well POSM would work if you had one in each village with MAN connections between and having the POSMs sync among themselves, sharing the data in near-real time.  This would be beneficial as there would be a backup of the data in the event one of the POSM devices died and could add some redundancy.  Providing connectivity could also aid in communications between sites through IRC or XMPP.

Lots of ideas…  Lots of options…

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  1. 2016-08-10 at 00:31 EDT

    I’ve had been experimenting with Traccar (https://www.traccar.org/). A friend wanted a near-real-time display of his trucks for his dispatcher and it seemed to fit his needs.

    The client is nice in that it will store data points on the phone until a connection to the server is available. I’d been limiting updates to when Wi-Fi was available. I’m not sure what the upper end is but I’ve gone 5 days between connections. Depending on settings, it can be a lot of data points.

    Not sure if it’s a feature but the client-to-server communication is simple enough that you can replace the server with your own code. Having a book or two about coding front-ends with OSM is valuable. I’ve been using one from Packt Publishing.

    The one draw-back: the software appeared to be a “finicky” about what phones on which it would install/run. Newer phones would report with higher accuracy (more digits to the right of the “.”).

    Certain older phones would “drift” while remaining stationary. It was noticeable enough that, overnight, one of his trucks would “drift” about a quarter mile. Once the truck started moving again, it would “snap back”. This appeared to be a problem with the phone and not the software.

    – Tim

  2. Mark Turner
    2016-08-28 at 14:51 EDT

    Hey Eric, any interest in getting a citywide community WiFi network going? Setting up a couple of cantennas and seeing what we can do? I’ve been mulling the idea over for a while now and think it would be fun to get something started. What do you think?

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