Today I went on a twitch: birding slang for making a specific journey to see a rare/unusual bird. Before I set off I entered the grid co-ordinates from a birding site, and noted that my Garmin OSM map had little detail, so I also carried along my usual OSM kit.
When I returned I discovered that most of the detail had been entered since mid-April, thanks to particular energetic on-the-ground mapping by will7777 in SE Derbyshire, but also lots of use of the recently released Ordnance Survey data. I was able to add a few extra paths, and see enough to add some additional POIs. Of course I travelled back a slightly circuitous route to validate streetnames recently sourced from the OS Data.
What really struck me is how important on-the-ground survey still is.
The OS Data shows a large stretch of woodland (OSM way 57959537) is not actually woodland, but is mostly wetland consisting of large beds of pond sedges. This image shows a powerline (OSM way 59359478) crossing the wetland area, with the wooded area considerably to the N & W of the powerline. This geograph photo shows the same area from a lower viewpoint, and interestingly records the traditional local name, Manner (or Manor) Floods. The powerline on OSM has been sourced from the OS VectorData Map layer. View the same area on Where's the Path. Armchair mappers beware!
And the bird? Images here and videos here (not mine).