While working on HOT Typhoon Haiyan mapping I noticed a whole area moved about 14m to the west while verify a job tile in task manager. Using JOSM I looked into the history of one node and found the changeset where the nodes were moved.

I noticed the user had only a few changesets. It could be that the user acciential moved the area. But I’m not sure, there may always be a reason. So I wrote a message to the user, tried to be polite and added the sentence «Under no circumstance this little critics should stop you from further mapping».

A few hours later the user responded with a elaborate answer, explaining he noticed an offset to the background and tried to fix it. He also noted that this wouldn’t stop him from further mapping. This was my biggest concern that he was offended.

It seems very reasonable. In the changeset I saw he used the JOSM editor, so it’s likely he accidentially added a aerial imagery offset. His other changesets all looked sane. I responded with some hints and offered to help.

We agreed that I fix it for him, so I’ve had my first case of a kind of revert. I checked the documentation to see what options are available. One seems to be the revert plugin for JOSM. Well I don’t really wanted to revert the whole changeset, I just want to move it back.

Fortunately I found the «Changeset Manager» in JOSM («Window» Menu). So it was easy to enter the changeset number, load the whole changeset. Then I downloaded the affected area, big enough to surely include the whole changeset. Then I added the Bing aerial imagery layer as reference. Finally I opened the changeset manager again, clicked the button «Select the primitives in the content of this changeset in the current data layer», and voilà, all moved items are selected. Now I had just to move the items back, using the background image as guidance. Of course a dialog popped up, warning me I’ve had just moved more than 20 objects: Yes I’m sure! Finally I upload the new changeset and add a sane commit message.

That was easy.

~Andy

I'm just back from Linuxtag 2009. Today I listened to an excellent talk by Jochen Topf about quality control in OSM. The talk was a good digest of the ideas spread in the last months:

We don't need and don't have a central quality control body, but a crowdsourcing quality control progress. A broad collection of tools emerged in the last year to help getting good quality data: The OSM Inspector, the JOSM Validator, the ITO OSM Mapper, the "unmapped places" heuristics (e.g. from Gary68), only to name a few. There are also published lists of streets from goverment to compare against. He did also show the tool used to check the progress of time limited ortho photography provided by LVG Bayern. I intend to research if we could also use this tool for our canton Neuchâtel, were we also got ortho photos.

But not only Jochen Topf did well: The people at the OSM booth did also a good job. Even if the booth was quite small and in the edge of the hall, it was covered with nice map posters from all over the place. The booth was always crowded - as usual...

I only missed the group of regular meeting this year.

~Andy

Yesterday was a small mapping party in Bremgarten AG, organized by Kire_ and mgeiser. It was located in KuZeB where we had an internet connection and drinks.
We where three experienced mappers and six more or less beginners, some of them didn't even had an OSM account before the event. They lerned very well and so we surveyed the place for an hour and edited the rest of the day. I only edited a single way by myself as I was instructing one of the newcomer.

The city was only mapped partial when we started. Now it looks quite good, even if there is more work required.

~Andy

I've met some people from Germany at LinuxTag OSM booth and Berlin meeting at Friday night.

It was a cosy meeting with peoples known from talk-de list, the OSM booth peoples and native Berliner. We could interchange advices and hints. We talked about tagging schema, our prefered way to map and what we are missing most (The need for OSM software developpers for instance).

I'm hopefully we can repeat that at next LinuxTag.

~Andy

I had today the opportunity to drive secondaries and primaries on median strip. http://www.slowup-schaffhausen-hegau.ch

I've had fun in ski holiday last week. Beautiful weather and a lot of snow in Zermatt, Switzerland. So I started to map my first aerial ways and pistes by carry my receiver downhill.

So I joined the Piste Maps [1] project.

What already works are simple aerialway [2], but only with osmarender, not mapnik. Pistes [3] are still in early discussion phase, but I already tried some of the tags. They seems to work fine. But they still needs some cleanup.

Happy skiing or snowbording, the next ski holiday is coming!

Cheers, Andy

[1] http://wiki.openstreetmap.org/index.php/WikiProject_Piste_Maps
[2] http://wiki.openstreetmap.org/index.php/Key:aerialway
[3] http://wiki.openstreetmap.org/index.php/Proposed_features/Piste_Maps