Further to what LivingWithDragons said - I live in Cambridge and the data here is genuinely way better than Google's is. No disrespect to gmap intended - they have excellent and *consistent* coverage over much of the world. It's just not as good as OSM in a number of well surveyed areas. I can't take credit for the vast majority of surveying around my home town. I am putting in quite a lot of miles surveying footpaths and bridleways, which leads me to another OSM advantage - OSM includes more map features than Google (though Google tends to have significantly better coverage of shops and businesses).

For not-directly-accessible features like streams there are a number of possible techniques:
* Often you can trace from the Yahoo satellite maps, if available (these are displayed by default in the Potlatch editor and there's a plugin to display them in JOSM. Traces created from them are suitable, license-wise, for OSM).
* Landsat imagery is available for (AFAIK) the whole world and can sometimes help you get an approximate trace. You can display this in JOSM, I don't know about Potlatch.
* npemap.org.uk provides out-of-copyright Ordnance Survey maps (for the UK) which can also be traced, though you have to take care to line them up with existing map data or they come out quite inaccurate.
* Finally, it's possible to connect up streams by more traditional survey techniques: going to crossing points (bridges, etc) and joining them up, taking bearings, triangulation, etc.

Hi David,

Sorry I didn't make it to this one, hopefully I'll be able to attend some future mapping parties, though. The progress that you've made with Bury already looks pretty amazing.

Cheers,
Mark

Congratulations! It's a great feeling to have your edits show up for the first time. Also, the Osmarender tiles update much faster (and you can explicitly ask for updates on tiles if you need to).

There are some tags for disused / abandoned railways. Would any of those be suitable for the stretches you looked at?

Anyhow, nice work on keeping things up-to-date. As a "living document", like wikipedia, OSM should be able to stay more up-to-date than other maps, eventually.

osm.wiki/index.php/New_Popular_Edition

Has instructions on how to realign the NPE layer with the existing ways for more accurate tracing. I've been finding I can locally line up the NPE map with some ways but that there seems to be some "drift" further away from the features I lined up. I've been re-aligning the NPE layer with some features nearby to whatever I'm currently editing in hope that it will minimise the errors introduced.

Sometimes you can use a combination of NPE and satellite maps, or of NPE and surveying in order to maximise the accuracy of the trace and to get names for things. NPE is particularly useful for finding the paths and names of things like streams, which are typically hard to survey.

It's great fun having a real GPS unit, though - it can make you a lot more productive.

Congratulations!

Depending on where you live, you might be able to use local knowledge + the Yahoo satellite maps provided by Potlatch (the online editor) to improve the local maps. When I've not been able to go out GPS-ing I sometimes do this anyhow. Footways, street names, drainage ditches (and other landmarks) bus stops, tracing round the outlines of major buildings - all these things are useful.

Whilst you're waiting for the GPS you might also like to learn a bit about JOSM, which I've found makes full blown surveying + mapping much easier to do once you have a GPS. With the right plugin, you can also overlay out-of-copyright OS maps (if you're in the UK) which can be useful for tracing over (footpaths tend to change over time but rivers and streams can usefully be traced).

When you edit stuff, switch to the Osmarender view (use the "+" sign at the top right of the map view), which updates more regularly. If you want to request part of it to be updated, you can do so here: http://tah.openstreetmap.org/Browse/slippy/

Hope this is useful to you! There's lots to do and lots to learn about. Have fun!