[OSM-talk] A plea for meaning ful changeset comments

[Andrew Errington]

On Fri, 30 Jul 2010 21:27:43 John F. Eldredge wrote:
> I have to admit that I am bad about not bothering to enter a comment,
> particularly if all I have been doing is fixing the alignment of streets to
> better conform to the Yahoo aerial view.

<snip> 

Don't forget, the Yahoo! aerials might not be exactly aligned in all areas.  I 
have found here in Korea the aerials are a little off in some places, but 
correct in others.  I generally move the aerial layer until some obvious 
feature lines up with a GPS trace (either my own, or downloaded), then I 
start tracing other features from the aerials.  For example, in my town the 
aerials are off by about 10m south and 8m east.  I have to slide the layer up 
and left to align to the GPS.

Of course, it's true the GPS traces are also off by 5, 10, or more metres, but 
you can overcome this by taking the average of many traces along the same 
road.  In my case, the obvious aerial feature I use is an oval running track.  
I have collected several GPS traces of this track, and they all agree with 
each other.

I apologise if you silently inferred that "of course I align the aerials first 
before I start fixing streets", but maybe this is new information for some 
people.

Best wishes,

Andrew

PS I always try and put some changeset comment in, but I had/have no idea if 
anyone reads them.  I also make mistakes such as not changing the comment if 
I do two changesets in a row, or sometimes leaving the comment blank.  Oh 
well.