Import/Catalogue/Jefferson Parish Addresses and Buildings

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This is an import of building footprints and outlines covering Jefferson Parish, Louisiana using the parish's planning department data. The import is currently (as of 15 November 2022) wrapping up. The bulk of the import is done, and the rest of the work is reviewing features that the import script marked with warnings.

Import Accounts

System-users-3.svgAnonymousAlligator_JeffParishImport (on osm, edits, contrib, heatmap, chngset com.)

Schedule

TBD

Import Data

Background

The source data is available as shapefiles on GitHub. You can download a ZIP file of this repository.

Data source site: <http://geoportal.jeffparish.net/public>. HTTP only as of 1 May 2022. There appears to be no public bulk download; AnonymousAlligator requested the data via an email to JeffMap@jeffparish.net.

Data license: There is no explicit license listed, only a disclaimer. Permission was obtained via email.

On 19 April 2022, AnonymousAlligator sent:

Just following up on this, we need to confirm whether there are any attribution requirements or other copyright obligations before we import this data into OpenStreetMap.

On 20 April 2022, they received a response:

None that I am aware of currently. Sorry I missed the email. Our filter pushes your messages into my spam folder.

Import Type

This is a one-time import.

Data Reduction & Simplification

A large number of building footprints already exist. We need to add address tags to them and not duplicate them.

Round buildings have way too many points. The import script simplifies them.

Tagging Plans

We will use the addr:housenumber, addr:street, addr:city, addr:postcode, addr:unit, and building=yes tags.

Changeset Tags

These tags are added by the import script, and JOSM will apply them for you.

Data Transformation

We'll be using this script to create OSM changesets, then reviewing and uploading them via JOSM. The script runs some basic validations, most notably checking addresses against existing street names. Changes that fail this validation are split into a separate result set.

The script tries to square building outlines, but it only does this if the difference is small (>95% similarity). It also simplifies outlines with more than 100 nodes.

Data Transformation Results

.osm files ready to open in JOSM are included in the repository under the osm-changes folder.

Data Merge Workflow

Team Approach

Several people have expressed interest in helping with the import, among them: (please add your username if you want to help)

We plan to split the change files between participants to review and upload.

References

TBD

Workflow

  1. Generate OSM changeset files (posted in the GitHub repository)
    • Size policy: Changes are split into a tile grid at zoom level 15.
  2. I recommend using the Address Tags Validator style in JOSM. Go to "View" -> "Map Paint Styles" -> "Map paint preferences" and add it.
  3. For each validated file:
    1. Load the file in JOSM
    2. Click "Imagery" -> "Mapbox Satellite"
    3. Click "File" -> "Update data" (or click ctrl+U)
    4. Make sure the data looks correct. Try to look over every building and make sure there's nothing wrong (it matches what you see on the aerial imagery, addresses are in order and don't have nonsense values, etc.)
    5. Run the validators. Fix any issues.
      • Duplicate house numbers: In many cases, the duplicate addresses are nearby and you just need to keep one and pick the rest. Sometimes the duplicate addresses are in exactly the same place.
      • Empty way: You forgot to click "File" -> "Update data"
      • Overlapping buildings: Fix the geometry so it doesn't overlap.
    6. Upload the changeset. Make sure you're on an import account and NOT your usual OSM account.
  4. For each file with warnings:
    1. Read the warnings log that was generating along with the change file. It will describe why validation failed.
    2. Most of the issues are mismatches between street names in the parish's database and ours. You will need to decide which name is correct. If it's the one in OSM, use JOSM to edit the addresses. If it's the one in the parish database, upload the changes and, separately, edit the street in OSM. Make sure you include every street segment in your edit.
    3. If you can't figure out which name is correct from Streetside or other clues, import the addresses anyway, then leave a note on the map so it can be surveyed later.

Conflation

The import script handles conflation. If there are any issues with conflation, please file an issue on the GitHub repo or message @AnonymousAlligator in the OSM US Slack.

See also

Email to imports@openstreetmap.org: https://lists.openstreetmap.org/pipermail/imports/2022-May/006849.html

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