Part of our series of diaries sharing experiences on the ongoing LA Building Import into OpenStreetMap. Last month, we talked about the tools. Today, it’s all about the data.

Just last week, we’ve hit 1.1 million buildings imported in LA City!
A great milestone as we are in the final stretch of import, validation and clean-up for LA City. Here’s a few map-shots on what happened in the last couple of months.

What happened?

We made sure that the import process followed the community accepted guidelines. Instead of importing everything with scripts/bots, we used the Tasking Manager to allow volunteers to take part. We divided LA City into four TM projects and organized mapathons within LA City to kick start the process. The animation below shows the weekly progress starting from Southside all the way to SF Valley. Large chunks of buildings were added during and after every mapathon.

Weekly progress, March - July 2016.

We asked volunteers to use a dedicated account and over 100 usernames participated. You can see this checkerboard pattern when you color the buildings by username/id.

Colored by user ID, > 100 usernames.

Before the import, a lot of buildings already exist. In recognition and respect to the mappers before us, we made sure that existing buildings were properly merged/conflated (in JOSM, we use the Replace Geometry tool). This is a tedious process but this is how it should be done. By doing this, we are keeping the editing history of existing buildings.

Feature version. Blue = v1 to Yellow > v4.

What was imported?

Aside from the good quality of building footprint, we included several tags that describes every building. This is not visible in our default map rendering, but these tags exist in most of the data we imported.

Building types

We’ve included building types based on LA Country’s Assessors information.

Colored by building type.

Year the building was originally constructed

There’s a lot of history in the urban expansion of Los Angeles starting from the pueblo in 1700s up to today. The import data has a year_built attribute which we included in the import. You can now see the city’s settlement history in OpenStreetMap.

Colored by year built, 1800 - 2015.

Building heights!

Rendered in Mapbox gl-js

These are a few of the tags we’ve added. I’m excited to see what the community creates out of this data. Our friends at MaptimeLA started experimenting with the data already!

Photo by MaptimeLA.

Are you planning on using this data in your own map? Catch the team this weekend at the SOTM-US and show us what you created!

More info about the import is available in the following links:

• Github - https://github.com/osmlab/labuildings/issues/
• Chat - https://gitter.im/osmlab/labuildings
• Wiki - osm.wiki/Los_angeles,_California/Buildings_Import