Recent diary entries
It's long been a goal of mine to fill in landuse and landcover information for the Columbus area. In previous efforts, I found myself spending a lot of time tracing around the edges of a large connected area of farmland, or woods, or residential development, and then when I finished that one multipolygon, I was too burnt out to do much more, so other landuses were done with less detail or left undone.
I've now solved that problem, by creating a work grid. This is essentially just an OSM data file that I load as a separate layer under my working data layer in JOSM, and I never upload the grid layer to the server because it doesn't correspond to any real objects. You can download the Columbus work grid if you like; it has upload="false" set in the XML so JOSM won't treat it as data that should be uploaded.
By focusing on one square-mile section at a time, I can map out landuse to my desired level of quality and detail. Now the remaining problem is that I only get around to mapping one or two grid squares each week, and there are 900 sections in the grid!
It seems rendering of ref tags on aeroway=runway is slightly broken. Runways always have two identifiers (one for each direction) and these are typically written together in the ref tag separated by a semicolon. It appears this semicolon is being replaced by a linefeed character, which makes sense for the current highway shield rendering style. But on runways, the value of the ref tag is still drawn along the way, and multiline text along a path doesn't seem to work, so instead we get a placeholder glyph that looks like a tiny "LF" in a box.
I think if we could get that semicolon replaced by an em dash ("—") instead (only for aeroway=runway of course) we'd have a satisfactory resolution.
It seems someone screwed up the US boundary relation: in an attempt to add some maritime boundaries, most of the old members were dropped. I'm currently on the task, however.
Complete the US boundary relation
Create the Alaska boundary relation
Fix any other state boundary relation problems I encounter
The process of improving Ohio's county boundaries has been ongoing for months. The work has been done mostly by myself and one other editor, using Potlatch.
Well, I recently tackled the boundaries in JOSM, and after a couple of nights of work, all the overlapping boundary ways have been merged, and proper relations created for each county.
The TIGER data in adjacent counties still needs to be properly joined over much of the state. I'll probably stick to Potlatch for that task. I can also improve the boundary accuracy that way. But now it will be easier to work with the boundaries as they are, with much fewer situations of half-finished counties with doubled boundaries that confuse other mappers. I've had people screw up my work because of that, but no more!
So yeah, the wiki says that JOSM is best for concentrated editing in a small area, but I find it's quite useful for manipulating very large structures when you don't want to load every little street in the region. The tricky part is getting JOSM to only load what you're interested in...