The ground survey mapping process undertaken by the Ramani Huria team depends upon high quality aerial imagery. Mappers collect data on site with the help of the field papers produced by drone images (mbtiles) that offer direction and location to the mapper. Equipped with GPS units, Ramani Huria team members mapped all city centre wards using this approach. These include Kivukoni, Kisutu, Kariakoo, Jangwani, Gerezani, Mchafukoge, Upanga Mashariki and Upanga Magharibi.

Ground survey process with the help of aerial imagery

  • First visit the fieldpapers website and make field papers for the area upon which you want to conduct a ground survey. If you don’t know how to produce the field papers, then see our ‘how to: data collection tools’ tech blog
  • After you have created the field papers, then get yourself a data collection form or a notebook to use for notes, as well as a GPS unit/OSM tracker for tracking and marking waypoints while conducting your ground survey. Once you’re packed, then you are good to go for data collection.
A mapper with field paper and GPS unit PHOTO CREDIT: Ramani Huria

A mapping team packed and ready for data collection

  • Using the field paper overview produced with drone imagery (mbtile), you can then locate your area of interest for data collection. After locating your area, power on your GPS unit/OSM tracker and wait for it to pick up a network. Then begin to walk through the site – identifying waypoints, notes, and tracks for the area. It’s important to take some pictures for you to refer to when some information may no longer be clear after data collection.
Map team tagging

A mapping team noting down the tags of the feature on notebook and GPS unit

  • Once you complete data collection, return to your working space and import the recorded tracks and waypoints from your GPS unit/OSM tracker to your computer via a USB cable. For more info on importing data from GPS unit or OSMtracker on the phone, go to “How to use a GPS unit” and “Mobile apps, including OSMtracker” tabs on our how to: data collection tools
Garmin Cable

Using a Garmin USB cable to import GPS unit data to a computer

  • After this, you can launch JOSM and add the recorded waypoints and tracks to the software. To do this, go to file>open and then locate your waypoints and tracks that were saved in your GPS unit or phone, then click “open” and they will appear on your JOSM editor window.
JOSM Waypoints

JOSM interface showing added waypoints and tracks

  • Next, load the drone imagery (mbtiles) by going to file>open, locating the mbtiles, and clicking “open” to add and display it on JOSM. Now your JOSM interface with high quality drone image (mbtiles) will look like this:
JOSM Mbtiles

JOSM interface showing drone imagery (mbtiles)

  • When the image is loaded, download the data layer of the site. After this, you can begin digitizing and tagging the information that you enter into JOSM. On downloading data layer and editing, please visits tabs “downloading data” and editing data on our “how to; tech blog series on JOSM
  • Finally, upload the data layer. The data layer will look like this:
JOSM and OSM

JOSM interface showing drone imagery (mbtiles) and OSM data layer

  • Congratulations, you have just completed a ground survey with the help of aerial imagery and contributed to developing OSM!

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