stragu's Diary

Just started mapping actively in Brisbane - I have a few questions!

Posted by stragu on 10 March 2013 in English.

Hi community!

I was an active Wikipedia contributor for a few years, and I am now contributing to MusicBrainz a fair bit. Even though I had an account on OSM for some time, I just started mapping actively around my street, which needed some love (the suburb still really does):

Around my street

I was wondering a few things, if anyone feels like helping a newbie:

Should I use “name” or “addr:name” to add the name of a shop in the building’s data?
I see that my building outlines look pretty different when using the closest and second closest Bing backgrounds, which probably depends on the age of the photos, and how they are fitted together - which one should I use? Should I just stick to the closest?
Does one need to add the street manually in each address data, or does the database somehow automatically give the name of the closest street to the building when someone searches for an address? (i.e. will the query “85 Lewis st” return results even though the building doesn’t have anything in “addr:street”?)

You can have a look at what I did there:

http://www.openstreetmap.org/?lat=-27.492626309394836&lon=153.03840547800064&zoom=18

Please let me know if there is something I am not doing right. I’ll probably have a few more questions later on :)

Really enjoying contributing!

Location: -27,493, 153,038

Discussion

Comment from z-dude on 10 March 2013 at 04:55

The name tag will be rendered. Sometimes when a building is built, it will have a name of it’s own, ie “Carlton Building”

Example: The Vancouver Art Gallery is in the old provincial courthouse building.

The addr:name is Vancouver Art Gallery the name attached to the building tag should match the building plaque on the building, but I’m sure that someone tagged the building name as Vancouver Art Gallery because that’s what we’ve locally known it as for decades.

Comment from z-dude on 10 March 2013 at 04:57

for addresses, I usually see people add an address node separate from the building, so a coffee shop, bank and grocery store will have different addresses or unit numbers in an address.

Comment from z-dude on 10 March 2013 at 04:58

Adding an address node also preserves the address in case anyone decides to delete and retrace a big complicated building.

Comment from porjo on 10 March 2013 at 08:43

Welcome aboard!

Does one need to add the street manually in each address data

Ideally, yes. However you can use interpolation - see:

http://wiki.openstreetmap.org/wiki/Addresses#Using_interpolation

building outlines look pretty different when using the closest and second closest Bing backgrounds

The closer image should be more accurate.

Comment from _sev on 10 March 2013 at 09:32

Also make sure that the imagery is aligned with GPS tracks. Sometimes the difference is several meters.

Comment from stragu on 10 March 2013 at 12:00

Thanks everyone for your comments!

_sev, how do you check the alignment?

Comment from Sanderd17 on 10 March 2013 at 12:30

To check alignment, fire up your GPS, walk around on some open place you know (like a parking, so you have a good reception), and remember where you walked (which side of the track etc).

Upload the GPX trace (you have to export it some way from your GPS) to OpenStreetMap, and check if there’s a constant deviation of the imagery vs your trace.

It’s normal that your trace is a bit imprecise, but if you see a 5m shift for your entire walk, you can assume the imagery is misaligned 5m.

On the other hand, a little shift isn’t that bad. As most GPS devices aren’t precise anyway, a 5m shift won’t matter. And it can be fixed in the future when even better images will be available.

I’ve noticed that the closest zoom images are older, and have a bigger shift (at least in Belgium). So you should probably drag your outlines to comply with the second-closest zoom.

Comment from Zartbitter on 11 March 2013 at 08:33

You can check how old Bing images are on this map: http://mvexel.dev.openstreetmap.org/bing/

In my surroundings image date varies from March 2001 to Winter March 2012 depending on zoom level

Comment from stragu on 11 March 2013 at 12:59

Great, thanks for the tip, Zartbitter! So much to learn!

Comment from Unusual User Name on 12 March 2013 at 00:00

Great to see someone else mapping in inner Brisbane!

In this area the highest zoom level is older than the next zoom level out, but you can trace better on the deepest zoom, so I only use the newer imagery if I have to.

I notice your buildings are not quite square. If you’re using Potlatch, a toolbar pops up, if you click “show more” you’ll see a square. Click on this when a polygon is selected and it will square it up.

It rarely works on polygons with more than 6 nodes, and sometimes not then, but I always use it after tracing.

Oh, and can I strongly encourage you to collect street address information, if it’s your local street and easy to do so.

Comment from stragu on 12 March 2013 at 01:28

Thanks for those tips, UUN! Good to know people are working on Brisbane!

I hope to do more addresses when I have a camera to do Photo Mapping.

Cheers!