In my neighbourhood, most buildings (~95%) are detached houses, although some are semi-detached houses. On OpenStreetMap, these buildings do not yet have a building tag.
Should I initially tag all of the buildings as building=detached and update the semi-detached houses later as I survey manually, or wait until I can confirm each building type one before tagging them?
That depends on your workflow. Which would be easier for you?
Both would be similarly difficult, but surveying the area would require some time (maybe a week?) and I might not get around to all the houses.
I’m wondering whether it’s better practice to have mostly correct data initially and then update it later, or to wait until I can be certain about the tags I upload.
this one
far too often people do “I will do it incorrectly, and later I will fix” and they never do the second part
There are lots of different options.
There are services available within OSM that include street-level photography. This includes Bing Streetside, Mapillary, KartaView, Mapilio and Panoramax (see image). Coverage of different places will vary a lot. You can of course go out with your own camera set up on foot, bike or car and add to these.
When mapping, if you are happy that a building is a detached house, you can tag it as building=house and house=detached. However, if you think that a certain building might be different, you can tag it as building=residential or building=yes until such time that you can check. If you apply the wrong tag, it can always be corrected later, but be careful to not blanket apply the wrong tag, as it can create a headache for later on.
Tip 1: For your own privacy, when you start mapping, don’t map your own house or place of work or study in your first few changesets. You can always map them later. Perhaps map some things in the town centre first.
Tip 2: If taking pictures or notes, be aware of your surroundings. Feel free to bring a friend. Some people are suspicious, whether that is nosy neighbours, over-protective parents or drug dealers.
Tip 3: Locally, we find that if there is a lot of tree cover, the photos are blurry or the buildings are ambiguous, counting the number of rear gardens / yards can be easier than counting the number of houses.
Yep, exactly. If you don’t know what it is, just keep it as building=yes.
Someone can always come along and tag things more specific later (like with StreetComplete).
You may also be interested in my tips and tutorials in:
I explained how I use JOSM’s awesome “Filters” feature to toggle ON/OFF building types, so I could quickly:
building=yes (“untouched” buildings) in a townand then be able to:
building=house, building=shed, or building=garage as needed.A few weeks ago, I just used this trick to tag more than 20k houses in Philadelphia!
See this area where—as far as the eye can see—entire city blocks were just the same exact “copy-and-paste” 2- and 3-story townhouses:
building=yes vs. other building types
building=houses tagged… with about 2.7k more untagged building=yes along those edges!)You turn left, right, or flip around? Yep, same exact design, same exact layout all the way into the distance:
Or here was another neighborhood to the northeast:
There’s about 500k more generic building=yeses in Philly… so pick a weird edge of the city and test it out! There’s plenty more to tag better! :)
(There’s some incredible 2024/2025 3-inch and 1-inch photography of the city too!)
More Tips: Another trick is to:
So if I get into “tag the houses” mode, I completely ignore many of those tiny/side buildings.
In Philly, you can see the address data was already imported a few years ago… so any sort of buildings WITHOUT addresses are “unimportant” (for now).
So, with the first pass, I could focus purely on tagging:
building=yes WITH an address.
building=house.Then, in a later pass, I could come on through and focus on:
building=yes WITHOUT address
building=garage.building=yes that are…
building=shed.This makes things much much faster, because you’re not trying to pull yourself into 8 different directions, constantly “context switching” and trying to wrangle certain tags one-by-one.
You use dashcam footage (or personal walking) to go down the entire city block:
Then, you only stop when there’s something odd:
building=commercial or building=retail.building=yes.and then you can continue with your current pattern.
Later on, you can always come back and “fill in the blanks”. And the more you tag correctly, the easier it becomes to focus and jump directly to those “outliers”! :)
You can use =house not =yes
Pairs of semi-detached houses (and terraces of houses) should not be given building=house, as it can be difficult afterwards to determine whether it is a pair of semi-detached houses when the existing tagging says it is just one house.
I forgot about this part, but it still doesn’t have to be =yes , and can have =residential
95% seems acceptable though, if =detached is usually used. You can easily find larger ones to correct.
Sure. If they are 100% residential buildings you can go with that value. Otherwise finding the wrong ones is rather difficult and easily some buildings get missed.
Obviously I trust that the author selects the correct ones to apply, with “my neighbourhood” hinting some knowledge about it. Strictly speaking for the confusion above, it’s not specified whether the building= are already split either.