The American Red Cross typically uses cloud-based mobile apps for its mapping work. These tools require an internet or cell phone connection to create, modify, or troubleshoot mapping surveys, and to upload data periodically. We recently conducted a project in an extremely remote area without dependable internet or cellular connectivity, where volunteers had to be offline and inaccessible for days or weeks at a time. To bridge this gap, we developed POSM (Portable OpenStreetMap) - letting us conduct major field efforts and work entirely offline for months at time.

POSM is a hardware device loaded with offline versions of software. POSM broadcasts a wireless signal that other devices can connect to in order to access tools that ordinarily require an internet connection.

Currently, POSM includes support for GIS and mapping tools used by the Missing Maps project:

POSM also includes software downloads and other useful apps for mapping and mobile data collection:

  • QGIS (open source desktop GIS)
  • OpenRefine (desktop data cleaning)
  • OsmAnd (navigation and GPX-recording app)
  • OpenSignal (crowdsourced cell signal-strength recording)
  • AppLock (to prevent volunteers from using up cell data for social networking, etc)

This means that any and all parts of a mapping workflow can happen offline. A user can pre-download files for an area of interest and then take POSM to the field. Mappers can do any and all of the following: fly a drone, process the imagery, use that to conduct a mapathon and create a base map, conduct a phone-based survey, add local detail to the base map with either paper-based or mobile phone-based methods, and pull the resulting data from the phones onto a local server. This cycle can be repeated over and over again to build off of field efforts. When a project finishes, users take POSM back to an area with internet and push the changes into OpenStreetMap and other relevant places.

POSM workflow

POSM has been used for mapping in West Africa, Sri Lanka, Comoros, Ecuador, and Seattle. It also has potential for use as a secure data-sharing tool (e.g. local intranet for disconnected areas) and many other applications. Additional software can be integrated into the devices.

Getting started

Interested in using POSM? This site walks through all the steps for obtaining, setting up, and using the device. If you are not sure whether or not POSM is right for your project, you can contact us and we can talk it through with you.

Please note that the POSM software is free and open-source; the American Red Cross developed this for its own projects but we are happy for others to benefit from it. We do not sell the devices, nor do we make a profit on the technology.