I went to visit my girlfriend in Hamburg over the weekend. Whilst I was there, we took the GPS and digital camera for a walk around a redeveloped gasworks. They've kept the original gasworks buildings and cleaned them up, putting in new interiors. The site now has a couple of hotels, a couple of restaurants, office space, residential flats, shops and a small park. Lots of features to map in a small space! The previous OSM coverage for this area was good but not complete. Google Maps coverage is also incomplete here; the redevelopment may mean that things have changed relatively recently, although interestingly the omissions in the two maps were very different.

There was already existing work in this area, so I set out to improve what was already there and fill in the gaps. It looked like quite a lot of tracing from Yahoo had been done already (building outlines, etc). I made some tweaks to this data - the Yahoo imagery seems slightly inaccurately positioned, so I aligned it to some reasonably consistent parts of my GPS tracing and then moved some of the existing features a small distance to better correspond to this. This is not a major visual difference but hopefully makes things slightly more accurate. Since the Yahoo imagery is slightly from the side of the buildings, I moved some of the outlines to correspond better with the footprint of the buildings, rather than the rooflines.

We paced round many unmapped footways, noted the positions of bicycle parking, steps, some unmapped roadways, playgrounds, etc. I also got some address details for some the buildings and tagged those too. When I got home I uploaded these changes, plus a load of extra tracing from Yahoo that I was able to do now that I understood how things looked on the ground.

The map for this area should be much more complete now and useful for giving directions. An interesting find during this exploration was a strange footpath going over what looked like an old industrial railway bridge into a small park on the other side of Gasstraße. It looked like the bridge had been fenced / taped off but that the fences had been moved (not necessarily officially!). We weren't really sure where it might go or if we were supposed to be there. We might go back and try to figure it out next time I visit.

The new stuff is currently on Osmarender but most / all of it should make it to the Mapnik render in the next day or so.