User:David.earl

From OpenStreetMap Wiki
Jump to: navigation, search

Hi,

I'm David Earl, living in Fulbourn, Cambridge, UK: a freelance photographer, designer and technologist: find me at frankieandshadow.com +44 7977 500014

Having got a GPS in September 2005, I systematically surveyed Cambridge, completing this in January 2006. Since then I've spread further out, and most of South Cambridgeshire is complete, together with the city of Ely and the market towns of Newmarket, Saffron Walden and Royston.

Mapping interests

I'm also the author of

North Star

Nstar.png David.earl is awarded the North Star


for completing all the roads in Cambridge

Mapping methodology

Surveying with a bike, I started out with a Garmin Geko 301 GPS and pencil and paper. However, this was time consuming and hard on the knees as it meant a lot of starting and stopping, and getting notepad out and so on. Adding waypoints on a Geko is not convenient (requires lots of button presses) so I tended to ride in a circle where I wanted to mark something that couldn't be related to a junction.

I then bought an Olympus digital voice recorder. I decided the easiest way to use this was with the recorder mounted on the handlebars so I could press record/pause without too much difficulty, and a headset. I used this arrangement for many months and it works fine. But it still required circling on the ground and meant I had trailing wires. It also meant pressing quite a small button on the recorder a couple of times at each location, which is tricky in gloves (needed on a bike in winter) and is not the safest thing to be doing on a bike.

So then I bought a Nokia N810 internet tablet. This general purpose miniature computer has a built in GPS and bluetooth. It also has available a mapping application called Maemo Mapper and a voice recorder called Maemo Recorder. Using a bluetooth headset (now available for under £10) I was able to make voice notes, and by adapting Maemo Mapper I was able to set it up so a prod anywhere on the large screen would record an auto-numbered waypoint (good with gloves, no need to divert my attention). A chunk of new work in JOSM then allowed for continuous audio recording - so I could just turn on the recorder on the N810 and put it in the background. By marking a synchronization point at the beginning, and touching the screen at each point where I needed to make a voice note, this then enables a click of a button in JOSM to play back the voice note corresponding to a marked location. It works well with gloves, it's much safer, I don't have to fiddle with wires or small buttons.

I've had to solve a few further problems with this approach:

  • the headset is particularly vulnerable to wind noise. After losing a couple of street names to the noise, I tried using some foam on the end of the headset and this works a treat - a chunk of a washing up sponge.
  • Maemo mapper records very quietly. I have to run it through an audio editor to amplify the result before it is usable. Mamo Recorder is a bit primitive - I'm sure it will improve.
  • The battery life on the N810 is about 4 hours 10 minutes. This is a bit limiting, but I've now got an external battery pack which extends it considerably. Though 4 hours is about my limit in one go anyway.

My ideal would be not to have to press any buttons at all. This could be achieved if I or someone could program JOSM's audio capabilities to recognise a particular phrase. Then we could add a waypoint vocally and sync it to the track by the time. (Voice activation to record separate snippets doesn't work because background noise outside is too strong - vehicles, wind, even birdsong).

For more details of how to use continuous audio mapping in JOSM, see JOSM help page on the subject